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mariadb/sql/sql_lex.cc
Igor Babaev 190e8a4c2a MDEV-23619 MariaDB crash on WITH RECURSIVE UNION ALL (CTE) query 
Due to a premature cleanup of the unit that specified a recursive CTE
used in the second operand of union the server fell into an infinite
loop in the reported test case. In other cases this premature cleanup
could cause other problems.
The bug is the result of a not quite correct fix for MDEV-17024. The
unit that specifies a recursive CTE has to be cleaned only after the
cleanup of the last external reference to this CTE. It means that
cleanups of the unit triggered not by the cleanup of a external
reference to the CTE must be blocked.
Usage of local table chains in selects to get external references to
recursive CTEs was not correct either because of possible merges of
some selects.

Also fixed a minor bug in st_select_lex::set_explain_type() that caused
typing 'RECURSIVE UNION' instead of 'UNION' in EXPLAIN output for external
references to a recursive CTE.
2020-11-13 08:07:20 -08:00

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/* Copyright (c) 2000, 2019, Oracle and/or its affiliates.
Copyright (c) 2009, 2020, MariaDB Corporation
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
/* A lexical scanner on a temporary buffer with a yacc interface */
#define MYSQL_LEX 1
#include <my_global.h>
#include "sql_priv.h"
#include "sql_class.h" // sql_lex.h: SQLCOM_END
#include "sql_lex.h"
#include "sql_parse.h" // add_to_list
#include "item_create.h"
#include <m_ctype.h>
#include <hash.h>
#include "sp_head.h"
#include "sp.h"
#include "sql_select.h"
#include "sql_cte.h"
static int lex_one_token(YYSTYPE *yylval, THD *thd);
/*
We are using pointer to this variable for distinguishing between assignment
to NEW row field (when parsing trigger definition) and structured variable.
*/
sys_var *trg_new_row_fake_var= (sys_var*) 0x01;
/**
LEX_STRING constant for null-string to be used in parser and other places.
*/
const LEX_STRING null_lex_str= {NULL, 0};
const LEX_STRING empty_lex_str= {(char *) "", 0};
/**
@note The order of the elements of this array must correspond to
the order of elements in enum_binlog_stmt_unsafe.
*/
const int
Query_tables_list::binlog_stmt_unsafe_errcode[BINLOG_STMT_UNSAFE_COUNT] =
{
ER_BINLOG_UNSAFE_LIMIT,
ER_BINLOG_UNSAFE_INSERT_DELAYED,
ER_BINLOG_UNSAFE_SYSTEM_TABLE,
ER_BINLOG_UNSAFE_AUTOINC_COLUMNS,
ER_BINLOG_UNSAFE_UDF,
ER_BINLOG_UNSAFE_SYSTEM_VARIABLE,
ER_BINLOG_UNSAFE_SYSTEM_FUNCTION,
ER_BINLOG_UNSAFE_NONTRANS_AFTER_TRANS,
ER_BINLOG_UNSAFE_MULTIPLE_ENGINES_AND_SELF_LOGGING_ENGINE,
ER_BINLOG_UNSAFE_MIXED_STATEMENT,
ER_BINLOG_UNSAFE_INSERT_IGNORE_SELECT,
ER_BINLOG_UNSAFE_INSERT_SELECT_UPDATE,
ER_BINLOG_UNSAFE_WRITE_AUTOINC_SELECT,
ER_BINLOG_UNSAFE_REPLACE_SELECT,
ER_BINLOG_UNSAFE_CREATE_IGNORE_SELECT,
ER_BINLOG_UNSAFE_CREATE_REPLACE_SELECT,
ER_BINLOG_UNSAFE_CREATE_SELECT_AUTOINC,
ER_BINLOG_UNSAFE_UPDATE_IGNORE,
ER_BINLOG_UNSAFE_INSERT_TWO_KEYS,
ER_BINLOG_UNSAFE_AUTOINC_NOT_FIRST
};
/* Longest standard keyword name */
#define TOCK_NAME_LENGTH 24
/*
The following data is based on the latin1 character set, and is only
used when comparing keywords
*/
static uchar to_upper_lex[]=
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,
96, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,123,124,125,126,127,
128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,247,216,217,218,219,220,221,222,255
};
/*
Names of the index hints (for error messages). Keep in sync with
index_hint_type
*/
const char * index_hint_type_name[] =
{
"IGNORE INDEX",
"USE INDEX",
"FORCE INDEX"
};
inline int lex_casecmp(const char *s, const char *t, uint len)
{
while (len-- != 0 &&
to_upper_lex[(uchar) *s++] == to_upper_lex[(uchar) *t++]) ;
return (int) len+1;
}
#include <lex_hash.h>
void lex_init(void)
{
uint i;
DBUG_ENTER("lex_init");
for (i=0 ; i < array_elements(symbols) ; i++)
symbols[i].length=(uchar) strlen(symbols[i].name);
for (i=0 ; i < array_elements(sql_functions) ; i++)
sql_functions[i].length=(uchar) strlen(sql_functions[i].name);
DBUG_VOID_RETURN;
}
void lex_free(void)
{ // Call this when daemon ends
DBUG_ENTER("lex_free");
DBUG_VOID_RETURN;
}
/**
Initialize lex object for use in fix_fields and parsing.
SYNOPSIS
init_lex_with_single_table()
@param thd The thread object
@param table The table object
@return Operation status
@retval TRUE An error occurred, memory allocation error
@retval FALSE Ok
DESCRIPTION
This function is used to initialize a lex object on the
stack for use by fix_fields and for parsing. In order to
work properly it also needs to initialize the
Name_resolution_context object of the lexer.
Finally it needs to set a couple of variables to ensure
proper functioning of fix_fields.
*/
int
init_lex_with_single_table(THD *thd, TABLE *table, LEX *lex)
{
TABLE_LIST *table_list;
Table_ident *table_ident;
SELECT_LEX *select_lex= &lex->select_lex;
Name_resolution_context *context= &select_lex->context;
/*
We will call the parser to create a part_info struct based on the
partition string stored in the frm file.
We will use a local lex object for this purpose. However we also
need to set the Name_resolution_object for this lex object. We
do this by using add_table_to_list where we add the table that
we're working with to the Name_resolution_context.
*/
thd->lex= lex;
lex_start(thd);
context->init();
if ((!(table_ident= new Table_ident(thd,
table->s->table_name,
table->s->db, TRUE))) ||
(!(table_list= select_lex->add_table_to_list(thd,
table_ident,
NULL,
0))))
return TRUE;
context->resolve_in_table_list_only(table_list);
lex->use_only_table_context= TRUE;
lex->context_analysis_only|= CONTEXT_ANALYSIS_ONLY_VCOL_EXPR;
select_lex->cur_pos_in_select_list= UNDEF_POS;
table->map= 1; //To ensure correct calculation of const item
table_list->table= table;
table_list->cacheable_table= false;
return FALSE;
}
/**
End use of local lex with single table
SYNOPSIS
end_lex_with_single_table()
@param thd The thread object
@param table The table object
@param old_lex The real lex object connected to THD
DESCRIPTION
This function restores the real lex object after calling
init_lex_with_single_table and also restores some table
variables temporarily set.
*/
void
end_lex_with_single_table(THD *thd, TABLE *table, LEX *old_lex)
{
LEX *lex= thd->lex;
table->map= 0;
table->get_fields_in_item_tree= FALSE;
lex_end(lex);
thd->lex= old_lex;
}
void
st_parsing_options::reset()
{
allows_variable= TRUE;
}
/**
Perform initialization of Lex_input_stream instance.
Basically, a buffer for pre-processed query. This buffer should be large
enough to keep multi-statement query. The allocation is done once in
Lex_input_stream::init() in order to prevent memory pollution when
the server is processing large multi-statement queries.
*/
bool Lex_input_stream::init(THD *thd,
char* buff,
unsigned int length)
{
DBUG_EXECUTE_IF("bug42064_simulate_oom",
DBUG_SET("+d,simulate_out_of_memory"););
m_cpp_buf= (char*) thd->alloc(length + 1);
DBUG_EXECUTE_IF("bug42064_simulate_oom",
DBUG_SET("-d,bug42064_simulate_oom"););
if (m_cpp_buf == NULL)
return TRUE;
m_thd= thd;
reset(buff, length);
return FALSE;
}
/**
Prepare Lex_input_stream instance state for use for handling next SQL statement.
It should be called between two statements in a multi-statement query.
The operation resets the input stream to the beginning-of-parse state,
but does not reallocate m_cpp_buf.
*/
void
Lex_input_stream::reset(char *buffer, unsigned int length)
{
yylineno= 1;
yylval= NULL;
lookahead_token= -1;
lookahead_yylval= NULL;
m_ptr= buffer;
m_tok_start= NULL;
m_tok_end= NULL;
m_end_of_query= buffer + length;
m_tok_start_prev= NULL;
m_buf= buffer;
m_buf_length= length;
m_echo= TRUE;
m_cpp_tok_start= NULL;
m_cpp_tok_start_prev= NULL;
m_cpp_tok_end= NULL;
m_body_utf8= NULL;
m_cpp_utf8_processed_ptr= NULL;
next_state= MY_LEX_START;
found_semicolon= NULL;
ignore_space= MY_TEST(m_thd->variables.sql_mode & MODE_IGNORE_SPACE);
stmt_prepare_mode= FALSE;
multi_statements= TRUE;
in_comment=NO_COMMENT;
m_underscore_cs= NULL;
m_cpp_ptr= m_cpp_buf;
}
/**
The operation is called from the parser in order to
1) designate the intention to have utf8 body;
1) Indicate to the lexer that we will need a utf8 representation of this
statement;
2) Determine the beginning of the body.
@param thd Thread context.
@param begin_ptr Pointer to the start of the body in the pre-processed
buffer.
*/
void Lex_input_stream::body_utf8_start(THD *thd, const char *begin_ptr)
{
DBUG_ASSERT(begin_ptr);
DBUG_ASSERT(m_cpp_buf <= begin_ptr && begin_ptr <= m_cpp_buf + m_buf_length);
uint body_utf8_length= get_body_utf8_maximum_length(thd);
m_body_utf8= (char *) thd->alloc(body_utf8_length + 1);
m_body_utf8_ptr= m_body_utf8;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= begin_ptr;
}
uint Lex_input_stream::get_body_utf8_maximum_length(THD *thd)
{
/*
String literals can grow during escaping:
1a. Character string '<TAB>' can grow to '\t', 3 bytes to 4 bytes growth.
1b. Character string '1000 times <TAB>' grows from
1002 to 2002 bytes (including quotes), which gives a little bit
less than 2 times growth.
"2" should be a reasonable multiplier that safely covers escaping needs.
*/
return (m_buf_length / thd->variables.character_set_client->mbminlen) *
my_charset_utf8_bin.mbmaxlen * 2/*for escaping*/;
}
/**
@brief The operation appends unprocessed part of pre-processed buffer till
the given pointer (ptr) and sets m_cpp_utf8_processed_ptr to end_ptr.
The idea is that some tokens in the pre-processed buffer (like character
set introducers) should be skipped.
Example:
CPP buffer: SELECT 'str1', _latin1 'str2';
m_cpp_utf8_processed_ptr -- points at the "SELECT ...";
In order to skip "_latin1", the following call should be made:
body_utf8_append(<pointer to "_latin1 ...">, <pointer to " 'str2'...">)
@param ptr Pointer in the pre-processed buffer, which specifies the
end of the chunk, which should be appended to the utf8
body.
@param end_ptr Pointer in the pre-processed buffer, to which
m_cpp_utf8_processed_ptr will be set in the end of the
operation.
*/
void Lex_input_stream::body_utf8_append(const char *ptr,
const char *end_ptr)
{
DBUG_ASSERT(m_cpp_buf <= ptr && ptr <= m_cpp_buf + m_buf_length);
DBUG_ASSERT(m_cpp_buf <= end_ptr && end_ptr <= m_cpp_buf + m_buf_length);
if (!m_body_utf8)
return;
if (m_cpp_utf8_processed_ptr >= ptr)
return;
size_t bytes_to_copy= ptr - m_cpp_utf8_processed_ptr;
memcpy(m_body_utf8_ptr, m_cpp_utf8_processed_ptr, bytes_to_copy);
m_body_utf8_ptr += bytes_to_copy;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= end_ptr;
}
/**
The operation appends unprocessed part of the pre-processed buffer till
the given pointer (ptr) and sets m_cpp_utf8_processed_ptr to ptr.
@param ptr Pointer in the pre-processed buffer, which specifies the end
of the chunk, which should be appended to the utf8 body.
*/
void Lex_input_stream::body_utf8_append(const char *ptr)
{
body_utf8_append(ptr, ptr);
}
/**
The operation converts the specified text literal to the utf8 and appends
the result to the utf8-body.
@param thd Thread context.
@param txt Text literal.
@param txt_cs Character set of the text literal.
@param end_ptr Pointer in the pre-processed buffer, to which
m_cpp_utf8_processed_ptr will be set in the end of the
operation.
*/
void Lex_input_stream::body_utf8_append_ident(THD *thd,
const LEX_STRING *txt,
const char *end_ptr)
{
if (!m_cpp_utf8_processed_ptr)
return;
LEX_STRING utf_txt;
CHARSET_INFO *txt_cs= thd->charset();
if (!my_charset_same(txt_cs, &my_charset_utf8_general_ci))
{
thd->convert_string(&utf_txt,
&my_charset_utf8_general_ci,
txt->str, (uint) txt->length,
txt_cs);
}
else
{
utf_txt.str= txt->str;
utf_txt.length= txt->length;
}
/* NOTE: utf_txt.length is in bytes, not in symbols. */
memcpy(m_body_utf8_ptr, utf_txt.str, utf_txt.length);
m_body_utf8_ptr += utf_txt.length;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= end_ptr;
}
extern "C" {
/**
Escape a character. Consequently puts "escape" and "wc" characters into
the destination utf8 string.
@param cs - the character set (utf8)
@param escape - the escape character (backslash, single quote, double quote)
@param wc - the character to be escaped
@param str - the destination string
@param end - the end of the destination string
@returns - a code according to the wc_mb() convension.
*/
int my_wc_mb_utf8_with_escape(CHARSET_INFO *cs, my_wc_t escape, my_wc_t wc,
uchar *str, uchar *end)
{
DBUG_ASSERT(escape > 0);
if (str + 1 >= end)
return MY_CS_TOOSMALL2; // Not enough space, need at least two bytes.
*str= (uchar)escape;
int cnvres= my_charset_utf8_handler.wc_mb(cs, wc, str + 1, end);
if (cnvres > 0)
return cnvres + 1; // The character was normally put
if (cnvres == MY_CS_ILUNI)
return MY_CS_ILUNI; // Could not encode "wc" (e.g. non-BMP character)
DBUG_ASSERT(cnvres <= MY_CS_TOOSMALL);
return cnvres - 1; // Not enough space
}
/**
Optionally escape a character.
If "escape" is non-zero, then both "escape" and "wc" are put to
the destination string. Otherwise, only "wc" is put.
@param cs - the character set (utf8)
@param wc - the character to be optionally escaped
@param escape - the escape character, or 0
@param ewc - the escaped replacement of "wc" (e.g. 't' for '\t')
@param str - the destination string
@param end - the end of the destination string
@returns - a code according to the wc_mb() conversion.
*/
int my_wc_mb_utf8_opt_escape(CHARSET_INFO *cs,
my_wc_t wc, my_wc_t escape, my_wc_t ewc,
uchar *str, uchar *end)
{
return escape ? my_wc_mb_utf8_with_escape(cs, escape, ewc, str, end) :
my_charset_utf8_handler.wc_mb(cs, wc, str, end);
}
/**
Encode a character with optional backlash escaping and quote escaping.
Quote marks are escaped using another quote mark.
Additionally, if "escape" is non-zero, then special characters are
also escaped using "escape".
Otherwise (if "escape" is zero, e.g. in case of MODE_NO_BACKSLASH_ESCAPES),
then special characters are not escaped and handled as normal characters.
@param cs - the character set (utf8)
@param wc - the character to be encoded
@param str - the destination string
@param end - the end of the destination string
@param sep - the string delimiter (e.g. ' or ")
@param escape - the escape character (backslash, or 0)
@returns - a code according to the wc_mb() convension.
*/
int my_wc_mb_utf8_escape(CHARSET_INFO *cs, my_wc_t wc, uchar *str, uchar *end,
my_wc_t sep, my_wc_t escape)
{
DBUG_ASSERT(escape == 0 || escape == '\\');
DBUG_ASSERT(sep == '"' || sep == '\'');
switch (wc) {
case 0: return my_wc_mb_utf8_opt_escape(cs, wc, escape, '0', str, end);
case '\t': return my_wc_mb_utf8_opt_escape(cs, wc, escape, 't', str, end);
case '\r': return my_wc_mb_utf8_opt_escape(cs, wc, escape, 'r', str, end);
case '\n': return my_wc_mb_utf8_opt_escape(cs, wc, escape, 'n', str, end);
case '\032': return my_wc_mb_utf8_opt_escape(cs, wc, escape, 'Z', str, end);
case '\'':
case '\"':
if (wc == sep)
return my_wc_mb_utf8_with_escape(cs, wc, wc, str, end);
}
return my_charset_utf8_handler.wc_mb(cs, wc, str, end); // No escaping needed
}
/** wc_mb() compatible routines for all sql_mode and delimiter combinations */
int my_wc_mb_utf8_escape_single_quote_and_backslash(CHARSET_INFO *cs,
my_wc_t wc,
uchar *str, uchar *end)
{
return my_wc_mb_utf8_escape(cs, wc, str, end, '\'', '\\');
}
int my_wc_mb_utf8_escape_double_quote_and_backslash(CHARSET_INFO *cs,
my_wc_t wc,
uchar *str, uchar *end)
{
return my_wc_mb_utf8_escape(cs, wc, str, end, '"', '\\');
}
int my_wc_mb_utf8_escape_single_quote(CHARSET_INFO *cs, my_wc_t wc,
uchar *str, uchar *end)
{
return my_wc_mb_utf8_escape(cs, wc, str, end, '\'', 0);
}
int my_wc_mb_utf8_escape_double_quote(CHARSET_INFO *cs, my_wc_t wc,
uchar *str, uchar *end)
{
return my_wc_mb_utf8_escape(cs, wc, str, end, '"', 0);
}
}; // End of extern "C"
/**
Get an escaping function, depending on the current sql_mode and the
string separator.
*/
my_charset_conv_wc_mb
Lex_input_stream::get_escape_func(THD *thd, my_wc_t sep) const
{
return thd->backslash_escapes() ?
(sep == '"' ? my_wc_mb_utf8_escape_double_quote_and_backslash:
my_wc_mb_utf8_escape_single_quote_and_backslash) :
(sep == '"' ? my_wc_mb_utf8_escape_double_quote:
my_wc_mb_utf8_escape_single_quote);
}
/**
Append a text literal to the end of m_body_utf8.
The string is escaped according to the current sql_mode and the
string delimiter (e.g. ' or ").
@param thd - current THD
@param txt - the string to be appended to m_body_utf8.
Note, the string must be already unescaped.
@param cs - the character set of the string
@param end_ptr - m_cpp_utf8_processed_ptr will be set to this value
(see body_utf8_append_ident for details)
@param sep - the string delimiter (single or double quote)
*/
void Lex_input_stream::body_utf8_append_escape(THD *thd,
const LEX_STRING *txt,
CHARSET_INFO *cs,
const char *end_ptr,
my_wc_t sep)
{
DBUG_ASSERT(sep == '\'' || sep == '"');
if (!m_cpp_utf8_processed_ptr)
return;
uint errors;
/**
We previously alloced m_body_utf8 to be able to store the query with all
strings properly escaped. See get_body_utf8_maximum_length().
So here we have guaranteedly enough space to append any string literal
with escaping. Passing txt->length*2 as "available space" is always safe.
For better safety purposes we could calculate get_body_utf8_maximum_length()
every time we append a string, but this would affect performance negatively,
so let's check that we don't get beyond the allocated buffer in
debug build only.
*/
DBUG_ASSERT(m_body_utf8 + get_body_utf8_maximum_length(thd) >=
m_body_utf8_ptr + txt->length * 2);
uint32 cnv_length= my_convert_using_func(m_body_utf8_ptr, txt->length * 2,
&my_charset_utf8_general_ci,
get_escape_func(thd, sep),
txt->str, txt->length,
cs, cs->cset->mb_wc,
&errors);
m_body_utf8_ptr+= cnv_length;
*m_body_utf8_ptr= 0;
m_cpp_utf8_processed_ptr= end_ptr;
}
void Lex_input_stream::add_digest_token(uint token, LEX_YYSTYPE yylval)
{
if (m_digest != NULL)
{
m_digest= digest_add_token(m_digest, token, yylval);
}
}
void Lex_input_stream::reduce_digest_token(uint token_left, uint token_right)
{
if (m_digest != NULL)
{
m_digest= digest_reduce_token(m_digest, token_left, token_right);
}
}
/*
This is called before every query that is to be parsed.
Because of this, it's critical to not do too much things here.
(We already do too much here)
*/
void lex_start(THD *thd)
{
LEX *lex= thd->lex;
DBUG_ENTER("lex_start");
DBUG_PRINT("info", ("Lex %p", thd->lex));
lex->thd= lex->unit.thd= thd;
lex->stmt_lex= lex; // default, should be rewritten for VIEWs And CTEs
DBUG_ASSERT(!lex->explain);
lex->context_stack.empty();
lex->unit.init_query();
lex->unit.init_select();
/* 'parent_lex' is used in init_query() so it must be before it. */
lex->select_lex.parent_lex= lex;
lex->select_lex.init_query();
lex->current_select_number= 1;
lex->curr_with_clause= 0;
lex->with_clauses_list= 0;
lex->with_clauses_list_last_next= &lex->with_clauses_list;
lex->clone_spec_offset= 0;
lex->value_list.empty();
lex->update_list.empty();
lex->set_var_list.empty();
lex->param_list.empty();
lex->view_list.empty();
lex->with_column_list.empty();
lex->with_persistent_for_clause= FALSE;
lex->column_list= NULL;
lex->index_list= NULL;
lex->prepared_stmt_params.empty();
lex->auxiliary_table_list.empty();
lex->unit.next= lex->unit.master=
lex->unit.link_next= lex->unit.return_to= 0;
lex->unit.prev= lex->unit.link_prev= 0;
lex->unit.slave= lex->current_select=
lex->all_selects_list= &lex->select_lex;
lex->select_lex.master= &lex->unit;
lex->select_lex.prev= &lex->unit.slave;
lex->select_lex.link_next= lex->select_lex.slave= lex->select_lex.next= 0;
lex->select_lex.link_prev= (st_select_lex_node**)&(lex->all_selects_list);
lex->select_lex.options= 0;
lex->select_lex.sql_cache= SELECT_LEX::SQL_CACHE_UNSPECIFIED;
lex->select_lex.init_order();
lex->select_lex.group_list.empty();
if (lex->select_lex.group_list_ptrs)
lex->select_lex.group_list_ptrs->clear();
lex->describe= 0;
lex->analyze_stmt= 0;
lex->explain_json= false;
lex->subqueries= FALSE;
lex->context_analysis_only= 0;
lex->derived_tables= 0;
lex->safe_to_cache_query= 1;
lex->parsing_options.reset();
lex->empty_field_list_on_rset= 0;
lex->select_lex.select_number= 1;
lex->part_info= 0;
lex->select_lex.in_sum_expr=0;
lex->select_lex.ftfunc_list_alloc.empty();
lex->select_lex.ftfunc_list= &lex->select_lex.ftfunc_list_alloc;
lex->select_lex.group_list.empty();
lex->select_lex.order_list.empty();
lex->select_lex.gorder_list.empty();
lex->m_sql_cmd= NULL;
lex->duplicates= DUP_ERROR;
lex->ignore= 0;
lex->spname= NULL;
lex->spcont= NULL;
lex->proc_list.first= 0;
lex->escape_used= FALSE;
lex->query_tables= 0;
lex->reset_query_tables_list(FALSE);
lex->expr_allows_subselect= TRUE;
lex->use_only_table_context= FALSE;
lex->parse_vcol_expr= FALSE;
lex->check_exists= FALSE;
lex->create_info.lex_start();
lex->verbose= 0;
lex->name= null_lex_str;
lex->event_parse_data= NULL;
lex->profile_options= PROFILE_NONE;
lex->nest_level=0 ;
lex->select_lex.nest_level_base= &lex->unit;
lex->allow_sum_func= 0;
lex->in_sum_func= NULL;
lex->used_tables= 0;
lex->only_view= FALSE;
lex->reset_slave_info.all= false;
lex->limit_rows_examined= 0;
lex->limit_rows_examined_cnt= ULONGLONG_MAX;
lex->var_list.empty();
lex->stmt_var_list.empty();
lex->proc_list.elements=0;
lex->save_group_list.empty();
lex->save_order_list.empty();
lex->win_ref= NULL;
lex->win_frame= NULL;
lex->frame_top_bound= NULL;
lex->frame_bottom_bound= NULL;
lex->win_spec= NULL;
lex->is_lex_started= TRUE;
DBUG_VOID_RETURN;
}
void lex_end(LEX *lex)
{
DBUG_ENTER("lex_end");
DBUG_PRINT("enter", ("lex: %p", lex));
lex_end_stage1(lex);
lex_end_stage2(lex);
DBUG_VOID_RETURN;
}
void lex_end_stage1(LEX *lex)
{
DBUG_ENTER("lex_end_stage1");
/* release used plugins */
if (lex->plugins.elements) /* No function call and no mutex if no plugins. */
{
plugin_unlock_list(0, (plugin_ref*)lex->plugins.buffer,
lex->plugins.elements);
}
reset_dynamic(&lex->plugins);
if (lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_PREPARE)
{
/*
Don't delete lex->sphead, it'll be needed for EXECUTE.
Note that of all statements that populate lex->sphead
only SQLCOM_COMPOUND can be PREPAREd
*/
DBUG_ASSERT(lex->sphead == 0 || lex->sql_command == SQLCOM_COMPOUND);
}
else
{
sp_head::destroy(lex->sphead);
lex->sphead= NULL;
}
DBUG_VOID_RETURN;
}
/*
MASTER INFO parameters (or state) is normally cleared towards the end
of a statement. But in case of PS, the state needs to be preserved during
its lifetime and should only be cleared on PS close or deallocation.
*/
void lex_end_stage2(LEX *lex)
{
DBUG_ENTER("lex_end_stage2");
/* Reset LEX_MASTER_INFO */
lex->mi.reset(lex->sql_command == SQLCOM_CHANGE_MASTER);
delete_dynamic(&lex->delete_gtid_domain);
DBUG_VOID_RETURN;
}
Yacc_state::~Yacc_state()
{
if (yacc_yyss)
{
my_free(yacc_yyss);
my_free(yacc_yyvs);
}
}
static int find_keyword(Lex_input_stream *lip, uint len, bool function)
{
const char *tok= lip->get_tok_start();
SYMBOL *symbol= get_hash_symbol(tok, len, function);
if (symbol)
{
lip->yylval->symbol.symbol=symbol;
lip->yylval->symbol.str= (char*) tok;
lip->yylval->symbol.length=len;
if ((symbol->tok == NOT_SYM) &&
(lip->m_thd->variables.sql_mode & MODE_HIGH_NOT_PRECEDENCE))
return NOT2_SYM;
if ((symbol->tok == OR_OR_SYM) &&
!(lip->m_thd->variables.sql_mode & MODE_PIPES_AS_CONCAT))
return OR2_SYM;
return symbol->tok;
}
return 0;
}
/*
Check if name is a keyword
SYNOPSIS
is_keyword()
name checked name (must not be empty)
len length of checked name
RETURN VALUES
0 name is a keyword
1 name isn't a keyword
*/
bool is_keyword(const char *name, uint len)
{
DBUG_ASSERT(len != 0);
return get_hash_symbol(name,len,0)!=0;
}
/**
Check if name is a sql function
@param name checked name
@return is this a native function or not
@retval 0 name is a function
@retval 1 name isn't a function
*/
bool is_lex_native_function(const LEX_STRING *name)
{
DBUG_ASSERT(name != NULL);
return (get_hash_symbol(name->str, (uint) name->length, 1) != 0);
}
/* make a copy of token before ptr and set yytoklen */
static LEX_STRING get_token(Lex_input_stream *lip, uint skip, uint length)
{
LEX_STRING tmp;
lip->yyUnget(); // ptr points now after last token char
tmp.length= length;
tmp.str= lip->m_thd->strmake(lip->get_tok_start() + skip, tmp.length);
lip->m_cpp_text_start= lip->get_cpp_tok_start() + skip;
lip->m_cpp_text_end= lip->m_cpp_text_start + tmp.length;
return tmp;
}
/*
todo:
There are no dangerous charsets in mysql for function
get_quoted_token yet. But it should be fixed in the
future to operate multichar strings (like ucs2)
*/
static LEX_STRING get_quoted_token(Lex_input_stream *lip,
uint skip,
uint length, char quote)
{
LEX_STRING tmp;
const char *from, *end;
char *to;
lip->yyUnget(); // ptr points now after last token char
tmp.length= length;
tmp.str=(char*) lip->m_thd->alloc(tmp.length+1);
from= lip->get_tok_start() + skip;
to= tmp.str;
end= to+length;
lip->m_cpp_text_start= lip->get_cpp_tok_start() + skip;
lip->m_cpp_text_end= lip->m_cpp_text_start + length;
for ( ; to != end; )
{
if ((*to++= *from++) == quote)
{
from++; // Skip double quotes
lip->m_cpp_text_start++;
}
}
*to= 0; // End null for safety
return tmp;
}
static size_t
my_unescape(CHARSET_INFO *cs, char *to, const char *str, const char *end,
int sep, bool backslash_escapes)
{
char *start= to;
for ( ; str != end ; str++)
{
#ifdef USE_MB
int l;
if (use_mb(cs) && (l= my_ismbchar(cs, str, end)))
{
while (l--)
*to++ = *str++;
str--;
continue;
}
#endif
if (backslash_escapes && *str == '\\' && str + 1 != end)
{
switch(*++str) {
case 'n':
*to++='\n';
break;
case 't':
*to++= '\t';
break;
case 'r':
*to++ = '\r';
break;
case 'b':
*to++ = '\b';
break;
case '0':
*to++= 0; // Ascii null
break;
case 'Z': // ^Z must be escaped on Win32
*to++='\032';
break;
case '_':
case '%':
*to++= '\\'; // remember prefix for wildcard
/* Fall through */
default:
*to++= *str;
break;
}
}
else if (*str == sep)
*to++= *str++; // Two ' or "
else
*to++ = *str;
}
*to= 0;
return to - start;
}
size_t
Lex_input_stream::unescape(CHARSET_INFO *cs, char *to,
const char *str, const char *end,
int sep)
{
return my_unescape(cs, to, str, end, sep, m_thd->backslash_escapes());
}
/*
Return an unescaped text literal without quotes
Fix sometimes to do only one scan of the string
*/
bool Lex_input_stream::get_text(LEX_STRING *dst, uint sep,
int pre_skip, int post_skip)
{
uchar c;
uint found_escape=0;
CHARSET_INFO *cs= m_thd->charset();
tok_bitmap= 0;
while (! eof())
{
c= yyGet();
tok_bitmap|= c;
#ifdef USE_MB
{
int l;
if (use_mb(cs) &&
(l = my_ismbchar(cs,
get_ptr() -1,
get_end_of_query()))) {
skip_binary(l-1);
continue;
}
}
#endif
if (c == '\\' &&
!(m_thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES))
{ // Escaped character
found_escape=1;
if (eof())
return true;
yySkip();
}
else if (c == sep)
{
if (c == yyGet()) // Check if two separators in a row
{
found_escape=1; // duplicate. Remember for delete
continue;
}
else
yyUnget();
/* Found end. Unescape and return string */
const char *str, *end;
str= get_tok_start();
end= get_ptr();
/* Extract the text from the token */
str += pre_skip;
end -= post_skip;
DBUG_ASSERT(end >= str);
if (!(dst->str= (char*) m_thd->alloc((uint) (end - str) + 1)))
{
dst->str= (char*) ""; // Sql_alloc has set error flag
dst->length= 0;
return true;
}
m_cpp_text_start= get_cpp_tok_start() + pre_skip;
m_cpp_text_end= get_cpp_ptr() - post_skip;
if (!found_escape)
{
memcpy(dst->str, str, dst->length= (end - str));
dst->str[dst->length]= 0;
}
else
{
dst->length= unescape(cs, dst->str, str, end, sep);
}
return false;
}
}
return true; // unexpected end of query
}
/*
** Calc type of integer; long integer, longlong integer or real.
** Returns smallest type that match the string.
** When using unsigned long long values the result is converted to a real
** because else they will be unexpected sign changes because all calculation
** is done with longlong or double.
*/
static const char *long_str="2147483647";
static const uint long_len=10;
static const char *signed_long_str="-2147483648";
static const char *longlong_str="9223372036854775807";
static const uint longlong_len=19;
static const char *signed_longlong_str="-9223372036854775808";
static const uint signed_longlong_len=19;
static const char *unsigned_longlong_str="18446744073709551615";
static const uint unsigned_longlong_len=20;
static inline uint int_token(const char *str,uint length)
{
if (length < long_len) // quick normal case
return NUM;
bool neg=0;
if (*str == '+') // Remove sign and pre-zeros
{
str++; length--;
}
else if (*str == '-')
{
str++; length--;
neg=1;
}
while (*str == '0' && length)
{
str++; length --;
}
if (length < long_len)
return NUM;
uint smaller,bigger;
const char *cmp;
if (neg)
{
if (length == long_len)
{
cmp= signed_long_str+1;
smaller=NUM; // If <= signed_long_str
bigger=LONG_NUM; // If >= signed_long_str
}
else if (length < signed_longlong_len)
return LONG_NUM;
else if (length > signed_longlong_len)
return DECIMAL_NUM;
else
{
cmp=signed_longlong_str+1;
smaller=LONG_NUM; // If <= signed_longlong_str
bigger=DECIMAL_NUM;
}
}
else
{
if (length == long_len)
{
cmp= long_str;
smaller=NUM;
bigger=LONG_NUM;
}
else if (length < longlong_len)
return LONG_NUM;
else if (length > longlong_len)
{
if (length > unsigned_longlong_len)
return DECIMAL_NUM;
cmp=unsigned_longlong_str;
smaller=ULONGLONG_NUM;
bigger=DECIMAL_NUM;
}
else
{
cmp=longlong_str;
smaller=LONG_NUM;
bigger= ULONGLONG_NUM;
}
}
while (*cmp && *cmp++ == *str++) ;
return ((uchar) str[-1] <= (uchar) cmp[-1]) ? smaller : bigger;
}
/**
Given a stream that is advanced to the first contained character in
an open comment, consume the comment. Optionally, if we are allowed,
recurse so that we understand comments within this current comment.
At this level, we do not support version-condition comments. We might
have been called with having just passed one in the stream, though. In
that case, we probably want to tolerate mundane comments inside. Thus,
the case for recursion.
@retval Whether EOF reached before comment is closed.
*/
bool consume_comment(Lex_input_stream *lip, int remaining_recursions_permitted)
{
// only one level of nested comments are allowed
DBUG_ASSERT(remaining_recursions_permitted == 0 ||
remaining_recursions_permitted == 1);
uchar c;
while (! lip->eof())
{
c= lip->yyGet();
if (remaining_recursions_permitted == 1)
{
if ((c == '/') && (lip->yyPeek() == '*'))
{
lip->yyUnput('('); // Replace nested "/*..." with "(*..."
lip->yySkip(); // and skip "("
lip->yySkip(); /* Eat asterisk */
if (consume_comment(lip, 0))
return true;
lip->yyUnput(')'); // Replace "...*/" with "...*)"
lip->yySkip(); // and skip ")"
continue;
}
}
if (c == '*')
{
if (lip->yyPeek() == '/')
{
lip->yySkip(); /* Eat slash */
return FALSE;
}
}
if (c == '\n')
lip->yylineno++;
}
return TRUE;
}
/*
MYSQLlex remember the following states from the following MYSQLlex()
@param yylval [out] semantic value of the token being parsed (yylval)
@param thd THD
- MY_LEX_EOQ Found end of query
- MY_LEX_OPERATOR_OR_IDENT Last state was an ident, text or number
(which can't be followed by a signed number)
*/
int MYSQLlex(YYSTYPE *yylval, THD *thd)
{
Lex_input_stream *lip= & thd->m_parser_state->m_lip;
int token;
if (lip->lookahead_token >= 0)
{
/*
The next token was already parsed in advance,
return it.
*/
token= lip->lookahead_token;
lip->lookahead_token= -1;
*yylval= *(lip->lookahead_yylval);
lip->lookahead_yylval= NULL;
return token;
}
token= lex_one_token(yylval, thd);
lip->add_digest_token(token, yylval);
switch(token) {
case WITH:
/*
Parsing 'WITH' 'ROLLUP' or 'WITH' 'CUBE' requires 2 look ups,
which makes the grammar LALR(2).
Replace by a single 'WITH_ROLLUP' or 'WITH_CUBE' token,
to transform the grammar into a LALR(1) grammar,
which sql_yacc.yy can process.
*/
token= lex_one_token(yylval, thd);
lip->add_digest_token(token, yylval);
switch(token) {
case CUBE_SYM:
return WITH_CUBE_SYM;
case ROLLUP_SYM:
return WITH_ROLLUP_SYM;
default:
/*
Save the token following 'WITH'
*/
lip->lookahead_yylval= lip->yylval;
lip->yylval= NULL;
lip->lookahead_token= token;
return WITH;
}
break;
default:
break;
}
return token;
}
static int lex_one_token(YYSTYPE *yylval, THD *thd)
{
uchar UNINIT_VAR(c);
bool comment_closed;
int tokval, result_state;
uint length;
enum my_lex_states state;
Lex_input_stream *lip= & thd->m_parser_state->m_lip;
LEX *lex= thd->lex;
CHARSET_INFO *const cs= thd->charset();
const uchar *const state_map= cs->state_map;
const uchar *const ident_map= cs->ident_map;
lip->yylval=yylval; // The global state
lip->start_token();
state=lip->next_state;
lip->next_state=MY_LEX_OPERATOR_OR_IDENT;
for (;;)
{
switch (state) {
case MY_LEX_OPERATOR_OR_IDENT: // Next is operator or keyword
case MY_LEX_START: // Start of token
// Skip starting whitespace
while(state_map[c= lip->yyPeek()] == MY_LEX_SKIP)
{
if (c == '\n')
lip->yylineno++;
lip->yySkip();
}
/* Start of real token */
lip->restart_token();
c= lip->yyGet();
state= (enum my_lex_states) state_map[c];
break;
case MY_LEX_ESCAPE:
if (!lip->eof() && lip->yyGet() == 'N')
{ // Allow \N as shortcut for NULL
yylval->lex_str.str=(char*) "\\N";
yylval->lex_str.length=2;
return NULL_SYM;
}
/* Fall through */
case MY_LEX_CHAR: // Unknown or single char token
case MY_LEX_SKIP: // This should not happen
if (c != ')')
lip->next_state= MY_LEX_START; // Allow signed numbers
return((int) c);
case MY_LEX_MINUS_OR_COMMENT:
if (lip->yyPeek() == '-' &&
(my_isspace(cs,lip->yyPeekn(1)) ||
my_iscntrl(cs,lip->yyPeekn(1))))
{
state=MY_LEX_COMMENT;
break;
}
lip->next_state= MY_LEX_START; // Allow signed numbers
return((int) c);
case MY_LEX_PLACEHOLDER:
/*
Check for a placeholder: it should not precede a possible identifier
because of binlogging: when a placeholder is replaced with
its value in a query for the binlog, the query must stay
grammatically correct.
*/
lip->next_state= MY_LEX_START; // Allow signed numbers
if (lip->stmt_prepare_mode && !ident_map[(uchar) lip->yyPeek()])
return(PARAM_MARKER);
return((int) c);
case MY_LEX_COMMA:
lip->next_state= MY_LEX_START; // Allow signed numbers
/*
Warning:
This is a work around, to make the "remember_name" rule in
sql/sql_yacc.yy work properly.
The problem is that, when parsing "select expr1, expr2",
the code generated by bison executes the *pre* action
remember_name (see select_item) *before* actually parsing the
first token of expr2.
*/
lip->restart_token();
return((int) c);
case MY_LEX_IDENT_OR_NCHAR:
{
uint sep;
if (lip->yyPeek() != '\'')
{
state= MY_LEX_IDENT;
break;
}
/* Found N'string' */
lip->yySkip(); // Skip '
if (lip->get_text(&yylval->lex_str, (sep= lip->yyGetLast()), 2, 1))
{
state= MY_LEX_CHAR; // Read char by char
break;
}
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_escape(thd, &yylval->lex_str,
national_charset_info,
lip->m_cpp_text_end, sep);
lex->text_string_is_7bit= (lip->tok_bitmap & 0x80) ? 0 : 1;
return(NCHAR_STRING);
}
case MY_LEX_IDENT_OR_HEX:
if (lip->yyPeek() == '\'')
{ // Found x'hex-number'
state= MY_LEX_HEX_NUMBER;
break;
}
/* fall through */
case MY_LEX_IDENT_OR_BIN:
if (lip->yyPeek() == '\'')
{ // Found b'bin-number'
state= MY_LEX_BIN_NUMBER;
break;
}
/* fall through */
case MY_LEX_IDENT:
const char *start;
#if defined(USE_MB) && defined(USE_MB_IDENT)
if (use_mb(cs))
{
result_state= IDENT_QUOTED;
int char_length= my_charlen(cs, lip->get_ptr() - 1,
lip->get_end_of_query());
if (char_length <= 0)
{
state= MY_LEX_CHAR;
continue;
}
lip->skip_binary(char_length - 1);
while (ident_map[c=lip->yyGet()])
{
char_length= my_charlen(cs, lip->get_ptr() - 1,
lip->get_end_of_query());
if (char_length <= 0)
break;
lip->skip_binary(char_length - 1);
}
}
else
#endif
{
for (result_state= c;
ident_map[(uchar) (c= lip->yyGet())];
result_state|= c)
;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
}
length= lip->yyLength();
start= lip->get_ptr();
if (lip->ignore_space)
{
/*
If we find a space then this can't be an identifier. We notice this
below by checking start != lex->ptr.
*/
for (; state_map[(uchar) c] == MY_LEX_SKIP ; c= lip->yyGet())
{
if (c == '\n')
lip->yylineno++;
}
}
if (start == lip->get_ptr() && c == '.' &&
ident_map[(uchar) lip->yyPeek()])
lip->next_state=MY_LEX_IDENT_SEP;
else
{ // '(' must follow directly if function
lip->yyUnget();
if ((tokval = find_keyword(lip, length, c == '(')))
{
lip->next_state= MY_LEX_START; // Allow signed numbers
return(tokval); // Was keyword
}
lip->yySkip(); // next state does a unget
}
yylval->lex_str=get_token(lip, 0, length);
/*
Note: "SELECT _bla AS 'alias'"
_bla should be considered as a IDENT if charset haven't been found.
So we don't use MYF(MY_WME) with get_charset_by_csname to avoid
producing an error.
*/
if (yylval->lex_str.str[0] == '_')
{
CHARSET_INFO *cs= get_charset_by_csname(yylval->lex_str.str + 1,
MY_CS_PRIMARY, MYF(0));
if (cs)
{
yylval->charset= cs;
lip->m_underscore_cs= cs;
lip->body_utf8_append(lip->m_cpp_text_start,
lip->get_cpp_tok_start() + length);
return(UNDERSCORE_CHARSET);
}
}
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_ident(thd, &yylval->lex_str, lip->m_cpp_text_end);
return(result_state); // IDENT or IDENT_QUOTED
case MY_LEX_IDENT_SEP: // Found ident and now '.'
yylval->lex_str.str= (char*) lip->get_ptr();
yylval->lex_str.length= 1;
c= lip->yyGet(); // should be '.'
lip->next_state= MY_LEX_IDENT_START; // Next is ident (not keyword)
if (!ident_map[(uchar) lip->yyPeek()]) // Probably ` or "
lip->next_state= MY_LEX_START;
return((int) c);
case MY_LEX_NUMBER_IDENT: // number or ident which num-start
if (lip->yyGetLast() == '0')
{
c= lip->yyGet();
if (c == 'x')
{
while (my_isxdigit(cs,(c = lip->yyGet()))) ;
if ((lip->yyLength() >= 3) && !ident_map[c])
{
/* skip '0x' */
yylval->lex_str=get_token(lip, 2, lip->yyLength()-2);
return (HEX_NUM);
}
lip->yyUnget();
state= MY_LEX_IDENT_START;
break;
}
else if (c == 'b')
{
while ((c= lip->yyGet()) == '0' || c == '1')
;
if ((lip->yyLength() >= 3) && !ident_map[c])
{
/* Skip '0b' */
yylval->lex_str= get_token(lip, 2, lip->yyLength()-2);
return (BIN_NUM);
}
lip->yyUnget();
state= MY_LEX_IDENT_START;
break;
}
lip->yyUnget();
}
while (my_isdigit(cs, (c = lip->yyGet()))) ;
if (!ident_map[c])
{ // Can't be identifier
state=MY_LEX_INT_OR_REAL;
break;
}
if (c == 'e' || c == 'E')
{
// The following test is written this way to allow numbers of type 1e1
if (my_isdigit(cs,lip->yyPeek()) ||
(c=(lip->yyGet())) == '+' || c == '-')
{ // Allow 1E+10
if (my_isdigit(cs,lip->yyPeek())) // Number must have digit after sign
{
lip->yySkip();
while (my_isdigit(cs,lip->yyGet())) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(FLOAT_NUM);
}
}
lip->yyUnget();
}
// fall through
case MY_LEX_IDENT_START: // We come here after '.'
result_state= IDENT;
#if defined(USE_MB) && defined(USE_MB_IDENT)
if (use_mb(cs))
{
result_state= IDENT_QUOTED;
while (ident_map[c=lip->yyGet()])
{
int char_length= my_charlen(cs, lip->get_ptr() - 1,
lip->get_end_of_query());
if (char_length <= 0)
break;
lip->skip_binary(char_length - 1);
}
}
else
#endif
{
for (result_state=0; ident_map[c= lip->yyGet()]; result_state|= c)
;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
}
if (c == '.' && ident_map[(uchar) lip->yyPeek()])
lip->next_state=MY_LEX_IDENT_SEP;// Next is '.'
yylval->lex_str= get_token(lip, 0, lip->yyLength());
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_ident(thd, &yylval->lex_str, lip->m_cpp_text_end);
return(result_state);
case MY_LEX_USER_VARIABLE_DELIMITER: // Found quote char
{
uint double_quotes= 0;
char quote_char= c; // Used char
while ((c=lip->yyGet()))
{
int var_length= my_charlen(cs, lip->get_ptr() - 1,
lip->get_end_of_query());
if (var_length == 1)
{
if (c == quote_char)
{
if (lip->yyPeek() != quote_char)
break;
c=lip->yyGet();
double_quotes++;
continue;
}
}
#ifdef USE_MB
else if (var_length > 1)
{
lip->skip_binary(var_length - 1);
}
#endif
}
if (double_quotes)
yylval->lex_str=get_quoted_token(lip, 1,
lip->yyLength() - double_quotes -1,
quote_char);
else
yylval->lex_str=get_token(lip, 1, lip->yyLength() -1);
if (c == quote_char)
lip->yySkip(); // Skip end `
lip->next_state= MY_LEX_START;
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_ident(thd, &yylval->lex_str, lip->m_cpp_text_end);
return(IDENT_QUOTED);
}
case MY_LEX_INT_OR_REAL: // Complete int or incomplete real
if (c != '.')
{ // Found complete integer number.
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return int_token(yylval->lex_str.str, (uint) yylval->lex_str.length);
}
// fall through
case MY_LEX_REAL: // Incomplete real number
while (my_isdigit(cs,c = lip->yyGet())) ;
if (c == 'e' || c == 'E')
{
c = lip->yyGet();
if (c == '-' || c == '+')
c = lip->yyGet(); // Skip sign
if (!my_isdigit(cs,c))
{ // No digit after sign
state= MY_LEX_CHAR;
break;
}
while (my_isdigit(cs,lip->yyGet())) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(FLOAT_NUM);
}
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(DECIMAL_NUM);
case MY_LEX_HEX_NUMBER: // Found x'hexstring'
lip->yySkip(); // Accept opening '
while (my_isxdigit(cs, (c= lip->yyGet()))) ;
if (c != '\'')
return(ABORT_SYM); // Illegal hex constant
lip->yySkip(); // Accept closing '
length= lip->yyLength(); // Length of hexnum+3
if ((length % 2) == 0)
return(ABORT_SYM); // odd number of hex digits
yylval->lex_str=get_token(lip,
2, // skip x'
length-3); // don't count x' and last '
return HEX_STRING;
case MY_LEX_BIN_NUMBER: // Found b'bin-string'
lip->yySkip(); // Accept opening '
while ((c= lip->yyGet()) == '0' || c == '1')
;
if (c != '\'')
return(ABORT_SYM); // Illegal hex constant
lip->yySkip(); // Accept closing '
length= lip->yyLength(); // Length of bin-num + 3
yylval->lex_str= get_token(lip,
2, // skip b'
length-3); // don't count b' and last '
return (BIN_NUM);
case MY_LEX_CMP_OP: // Incomplete comparison operator
lip->next_state= MY_LEX_START; // Allow signed numbers
if (state_map[(uchar) lip->yyPeek()] == MY_LEX_CMP_OP ||
state_map[(uchar) lip->yyPeek()] == MY_LEX_LONG_CMP_OP)
{
lip->yySkip();
if ((tokval= find_keyword(lip, 2, 0)))
return(tokval);
lip->yyUnget();
}
return(c);
case MY_LEX_LONG_CMP_OP: // Incomplete comparison operator
lip->next_state= MY_LEX_START;
if (state_map[(uchar) lip->yyPeek()] == MY_LEX_CMP_OP ||
state_map[(uchar) lip->yyPeek()] == MY_LEX_LONG_CMP_OP)
{
lip->yySkip();
if (state_map[(uchar) lip->yyPeek()] == MY_LEX_CMP_OP)
{
lip->yySkip();
if ((tokval= find_keyword(lip, 3, 0)))
return(tokval);
lip->yyUnget();
}
if ((tokval= find_keyword(lip, 2, 0)))
return(tokval);
lip->yyUnget();
}
return(c);
case MY_LEX_BOOL:
if (c != lip->yyPeek())
{
state=MY_LEX_CHAR;
break;
}
lip->yySkip();
tokval = find_keyword(lip,2,0); // Is a bool operator
lip->next_state= MY_LEX_START; // Allow signed numbers
return(tokval);
case MY_LEX_STRING_OR_DELIMITER:
if (thd->variables.sql_mode & MODE_ANSI_QUOTES)
{
state= MY_LEX_USER_VARIABLE_DELIMITER;
break;
}
/* " used for strings */
/* fall through */
case MY_LEX_STRING: // Incomplete text string
{
uint sep;
if (lip->get_text(&yylval->lex_str, (sep= lip->yyGetLast()), 1, 1))
{
state= MY_LEX_CHAR; // Read char by char
break;
}
CHARSET_INFO *strcs= lip->m_underscore_cs ? lip->m_underscore_cs : cs;
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_escape(thd, &yylval->lex_str, strcs,
lip->m_cpp_text_end, sep);
lip->m_underscore_cs= NULL;
lex->text_string_is_7bit= (lip->tok_bitmap & 0x80) ? 0 : 1;
return(TEXT_STRING);
}
case MY_LEX_COMMENT: // Comment
lex->select_lex.options|= OPTION_FOUND_COMMENT;
while ((c = lip->yyGet()) != '\n' && c) ;
lip->yyUnget(); // Safety against eof
state = MY_LEX_START; // Try again
break;
case MY_LEX_LONG_COMMENT: /* Long C comment? */
if (lip->yyPeek() != '*')
{
state=MY_LEX_CHAR; // Probable division
break;
}
lex->select_lex.options|= OPTION_FOUND_COMMENT;
/* Reject '/' '*', since we might need to turn off the echo */
lip->yyUnget();
lip->save_in_comment_state();
if (lip->yyPeekn(2) == '!' ||
(lip->yyPeekn(2) == 'M' && lip->yyPeekn(3) == '!'))
{
bool maria_comment_syntax= lip->yyPeekn(2) == 'M';
lip->in_comment= DISCARD_COMMENT;
/* Accept '/' '*' '!', but do not keep this marker. */
lip->set_echo(FALSE);
lip->yySkipn(maria_comment_syntax ? 4 : 3);
/*
The special comment format is very strict:
'/' '*' '!', followed by an optional 'M' and exactly
1-2 digits (major), 2 digits (minor), then 2 digits (dot).
32302 -> 3.23.02
50032 -> 5.0.32
50114 -> 5.1.14
100000 -> 10.0.0
*/
if ( my_isdigit(cs, lip->yyPeekn(0))
&& my_isdigit(cs, lip->yyPeekn(1))
&& my_isdigit(cs, lip->yyPeekn(2))
&& my_isdigit(cs, lip->yyPeekn(3))
&& my_isdigit(cs, lip->yyPeekn(4))
)
{
ulong version;
uint length= 5;
char *end_ptr= (char*) lip->get_ptr()+length;
int error;
if (my_isdigit(cs, lip->yyPeekn(5)))
{
end_ptr++; // 6 digit number
length++;
}
version= (ulong) my_strtoll10(lip->get_ptr(), &end_ptr, &error);
/*
MySQL-5.7 has new features and might have new SQL syntax that
MariaDB-10.0 does not understand. Ignore all versioned comments
with MySQL versions in the range 50700-999999, but
do not ignore MariaDB specific comments for the same versions.
*/
if (version <= MYSQL_VERSION_ID &&
(version < 50700 || version > 99999 || maria_comment_syntax))
{
/* Accept 'M' 'm' 'm' 'd' 'd' */
lip->yySkipn(length);
/* Expand the content of the special comment as real code */
lip->set_echo(TRUE);
state=MY_LEX_START;
break; /* Do not treat contents as a comment. */
}
else
{
#ifdef WITH_WSREP
if (WSREP(thd) && version == 99997 && thd->wsrep_exec_mode == LOCAL_STATE)
{
WSREP_DEBUG("consistency check: %s", thd->query());
thd->wsrep_consistency_check= CONSISTENCY_CHECK_DECLARED;
lip->yySkipn(5);
lip->set_echo(TRUE);
state=MY_LEX_START;
break; /* Do not treat contents as a comment. */
}
#endif /* WITH_WSREP */
/*
Patch and skip the conditional comment to avoid it
being propagated infinitely (eg. to a slave).
*/
char *pcom= lip->yyUnput(' ');
comment_closed= ! consume_comment(lip, 1);
if (! comment_closed)
{
*pcom= '!';
}
/* version allowed to have one level of comment inside. */
}
}
else
{
/* Not a version comment. */
state=MY_LEX_START;
lip->set_echo(TRUE);
break;
}
}
else
{
lip->in_comment= PRESERVE_COMMENT;
lip->yySkip(); // Accept /
lip->yySkip(); // Accept *
comment_closed= ! consume_comment(lip, 0);
/* regular comments can have zero comments inside. */
}
/*
Discard:
- regular '/' '*' comments,
- special comments '/' '*' '!' for a future version,
by scanning until we find a closing '*' '/' marker.
Nesting regular comments isn't allowed. The first
'*' '/' returns the parser to the previous state.
/#!VERSI oned containing /# regular #/ is allowed #/
Inside one versioned comment, another versioned comment
is treated as a regular discardable comment. It gets
no special parsing.
*/
/* Unbalanced comments with a missing '*' '/' are a syntax error */
if (! comment_closed)
return (ABORT_SYM);
state = MY_LEX_START; // Try again
lip->restore_in_comment_state();
break;
case MY_LEX_END_LONG_COMMENT:
if ((lip->in_comment != NO_COMMENT) && lip->yyPeek() == '/')
{
/* Reject '*' '/' */
lip->yyUnget();
/* Accept '*' '/', with the proper echo */
lip->set_echo(lip->in_comment == PRESERVE_COMMENT);
lip->yySkipn(2);
/* And start recording the tokens again */
lip->set_echo(TRUE);
lip->in_comment=NO_COMMENT;
state=MY_LEX_START;
}
else
state=MY_LEX_CHAR; // Return '*'
break;
case MY_LEX_SET_VAR: // Check if ':='
if (lip->yyPeek() != '=')
{
state=MY_LEX_CHAR; // Return ':'
break;
}
lip->yySkip();
return (SET_VAR);
case MY_LEX_SEMICOLON: // optional line terminator
state= MY_LEX_CHAR; // Return ';'
break;
case MY_LEX_EOL:
if (lip->eof())
{
lip->yyUnget(); // Reject the last '\0'
lip->set_echo(FALSE);
lip->yySkip();
lip->set_echo(TRUE);
/* Unbalanced comments with a missing '*' '/' are a syntax error */
if (lip->in_comment != NO_COMMENT)
return (ABORT_SYM);
lip->next_state=MY_LEX_END; // Mark for next loop
return(END_OF_INPUT);
}
state=MY_LEX_CHAR;
break;
case MY_LEX_END:
lip->next_state=MY_LEX_END;
return(0); // We found end of input last time
/* Actually real shouldn't start with . but allow them anyhow */
case MY_LEX_REAL_OR_POINT:
if (my_isdigit(cs,lip->yyPeek()))
state = MY_LEX_REAL; // Real
else
{
state= MY_LEX_IDENT_SEP; // return '.'
lip->yyUnget(); // Put back '.'
}
break;
case MY_LEX_USER_END: // end '@' of user@hostname
switch (state_map[(uchar) lip->yyPeek()]) {
case MY_LEX_STRING:
case MY_LEX_USER_VARIABLE_DELIMITER:
case MY_LEX_STRING_OR_DELIMITER:
break;
case MY_LEX_USER_END:
lip->next_state=MY_LEX_SYSTEM_VAR;
break;
default:
lip->next_state=MY_LEX_HOSTNAME;
break;
}
yylval->lex_str.str=(char*) lip->get_ptr();
yylval->lex_str.length=1;
return((int) '@');
case MY_LEX_HOSTNAME: // end '@' of user@hostname
for (c=lip->yyGet() ;
my_isalnum(cs,c) || c == '.' || c == '_' || c == '$';
c= lip->yyGet()) ;
yylval->lex_str=get_token(lip, 0, lip->yyLength());
return(LEX_HOSTNAME);
case MY_LEX_SYSTEM_VAR:
yylval->lex_str.str=(char*) lip->get_ptr();
yylval->lex_str.length=1;
lip->yySkip(); // Skip '@'
lip->next_state= (state_map[(uchar) lip->yyPeek()] ==
MY_LEX_USER_VARIABLE_DELIMITER ?
MY_LEX_OPERATOR_OR_IDENT :
MY_LEX_IDENT_OR_KEYWORD);
return((int) '@');
case MY_LEX_IDENT_OR_KEYWORD:
/*
We come here when we have found two '@' in a row.
We should now be able to handle:
[(global | local | session) .]variable_name
*/
for (result_state= 0; ident_map[c= lip->yyGet()]; result_state|= c)
;
/* If there were non-ASCII characters, mark that we must convert */
result_state= result_state & 0x80 ? IDENT_QUOTED : IDENT;
if (c == '.')
lip->next_state=MY_LEX_IDENT_SEP;
length= lip->yyLength();
if (length == 0)
return(ABORT_SYM); // Names must be nonempty.
if ((tokval= find_keyword(lip, length,0)))
{
lip->yyUnget(); // Put back 'c'
return(tokval); // Was keyword
}
yylval->lex_str=get_token(lip, 0, length);
lip->body_utf8_append(lip->m_cpp_text_start);
lip->body_utf8_append_ident(thd, &yylval->lex_str, lip->m_cpp_text_end);
return(result_state);
}
}
}
void trim_whitespace(CHARSET_INFO *cs, LEX_STRING *str, uint *prefix_length)
{
/*
TODO:
This code assumes that there are no multi-bytes characters
that can be considered white-space.
*/
*prefix_length= 0;
while ((str->length > 0) && (my_isspace(cs, str->str[0])))
{
(*prefix_length)++;
str->length --;
str->str ++;
}
/*
FIXME:
Also, parsing backward is not safe with multi bytes characters
*/
while ((str->length > 0) && (my_isspace(cs, str->str[str->length-1])))
{
str->length --;
}
}
/*
st_select_lex structures initialisations
*/
void st_select_lex_node::init_query()
{
options= 0;
sql_cache= SQL_CACHE_UNSPECIFIED;
linkage= UNSPECIFIED_TYPE;
no_table_names_allowed= 0;
uncacheable= 0;
}
void st_select_lex_node::init_select()
{
}
void st_select_lex_unit::init_query()
{
st_select_lex_node::init_query();
linkage= GLOBAL_OPTIONS_TYPE;
select_limit_cnt= HA_POS_ERROR;
offset_limit_cnt= 0;
union_distinct= 0;
prepared= optimized= executed= 0;
optimize_started= 0;
item= 0;
union_result= 0;
table= 0;
fake_select_lex= 0;
saved_fake_select_lex= 0;
cleaned= 0;
item_list.empty();
describe= 0;
found_rows_for_union= 0;
derived= 0;
is_view= false;
with_clause= 0;
with_element= 0;
columns_are_renamed= false;
}
void st_select_lex::init_query()
{
st_select_lex_node::init_query();
table_list.empty();
top_join_list.empty();
join_list= &top_join_list;
embedding= 0;
leaf_tables_prep.empty();
leaf_tables.empty();
item_list.empty();
min_max_opt_list.empty();
join= 0;
having= prep_having= where= prep_where= 0;
cond_pushed_into_where= cond_pushed_into_having= 0;
olap= UNSPECIFIED_OLAP_TYPE;
having_fix_field= 0;
having_fix_field_for_pushed_cond= 0;
context.select_lex= this;
context.init();
/*
Add the name resolution context of the current (sub)query to the
stack of contexts for the whole query.
TODO:
push_context may return an error if there is no memory for a new
element in the stack, however this method has no return value,
thus push_context should be moved to a place where query
initialization is checked for failure.
*/
parent_lex->push_context(&context, parent_lex->thd->mem_root);
cond_count= between_count= with_wild= 0;
max_equal_elems= 0;
ref_pointer_array.reset();
select_n_where_fields= 0;
select_n_reserved= 0;
select_n_having_items= 0;
n_sum_items= 0;
n_child_sum_items= 0;
hidden_bit_fields= 0;
fields_in_window_functions= 0;
subquery_in_having= explicit_limit= 0;
is_item_list_lookup= 0;
changed_elements= 0;
first_natural_join_processing= 1;
first_cond_optimization= 1;
parsing_place= NO_MATTER;
exclude_from_table_unique_test= no_wrap_view_item= FALSE;
nest_level= 0;
link_next= 0;
prep_leaf_list_state= UNINIT;
have_merged_subqueries= FALSE;
bzero((char*) expr_cache_may_be_used, sizeof(expr_cache_may_be_used));
select_list_tables= 0;
m_non_agg_field_used= false;
m_agg_func_used= false;
window_specs.empty();
window_funcs.empty();
}
void st_select_lex::init_select()
{
st_select_lex_node::init_select();
sj_nests.empty();
sj_subselects.empty();
group_list.empty();
if (group_list_ptrs)
group_list_ptrs->clear();
type= db= 0;
having= 0;
table_join_options= 0;
in_sum_expr= with_wild= 0;
options= 0;
sql_cache= SQL_CACHE_UNSPECIFIED;
ftfunc_list_alloc.empty();
inner_sum_func_list= 0;
ftfunc_list= &ftfunc_list_alloc;
linkage= UNSPECIFIED_TYPE;
order_list.elements= 0;
order_list.first= 0;
order_list.next= &order_list.first;
/* Set limit and offset to default values */
select_limit= 0; /* denotes the default limit = HA_POS_ERROR */
offset_limit= 0; /* denotes the default offset = 0 */
with_sum_func= 0;
with_all_modifier= 0;
is_correlated= 0;
cur_pos_in_select_list= UNDEF_POS;
cond_value= having_value= Item::COND_UNDEF;
inner_refs_list.empty();
insert_tables= 0;
merged_into= 0;
m_non_agg_field_used= false;
m_agg_func_used= false;
name_visibility_map= 0;
with_dep= 0;
join= 0;
lock_type= TL_READ_DEFAULT;
}
/*
st_select_lex structures linking
*/
/* include on level down */
void st_select_lex_node::include_down(st_select_lex_node *upper)
{
if ((next= upper->slave))
next->prev= &next;
prev= &upper->slave;
upper->slave= this;
master= upper;
slave= 0;
}
void st_select_lex_node::add_slave(st_select_lex_node *slave_arg)
{
for (; slave; slave= slave->next)
if (slave == slave_arg)
return;
if (slave)
{
st_select_lex_node *slave_arg_slave= slave_arg->slave;
/* Insert in the front of list of slaves if any. */
slave_arg->include_neighbour(slave);
/* include_neighbour() sets slave_arg->slave=0, restore it. */
slave_arg->slave= slave_arg_slave;
/* Count on include_neighbour() setting the master. */
DBUG_ASSERT(slave_arg->master == this);
}
else
{
slave= slave_arg;
slave_arg->master= this;
}
}
/*
include on level down (but do not link)
SYNOPSYS
st_select_lex_node::include_standalone()
upper - reference on node underr which this node should be included
ref - references on reference on this node
*/
void st_select_lex_node::include_standalone(st_select_lex_node *upper,
st_select_lex_node **ref)
{
next= 0;
prev= ref;
master= upper;
slave= 0;
}
/* include neighbour (on same level) */
void st_select_lex_node::include_neighbour(st_select_lex_node *before)
{
if ((next= before->next))
next->prev= &next;
prev= &before->next;
before->next= this;
master= before->master;
slave= 0;
}
/* including in global SELECT_LEX list */
void st_select_lex_node::include_global(st_select_lex_node **plink)
{
if ((link_next= *plink))
link_next->link_prev= &link_next;
link_prev= plink;
*plink= this;
}
//excluding from global list (internal function)
void st_select_lex_node::fast_exclude()
{
if (link_prev)
{
if ((*link_prev= link_next))
link_next->link_prev= link_prev;
}
// Remove slave structure
for (; slave; slave= slave->next)
slave->fast_exclude();
}
/**
@brief
Insert a new chain of nodes into another chain before a particular link
@param in/out
ptr_pos_to_insert the address of the chain pointer pointing to the link
before which the subchain has to be inserted
@param
end_chain_node the last link of the subchain to be inserted
@details
The method inserts the chain of nodes starting from this node and ending
with the node nd_chain_node into another chain of nodes before the node
pointed to by *ptr_pos_to_insert.
It is assumed that ptr_pos_to_insert belongs to the chain where we insert.
So it must be updated.
@retval
The method returns the pointer to the first link of the inserted chain
*/
st_select_lex_node *st_select_lex_node:: insert_chain_before(
st_select_lex_node **ptr_pos_to_insert,
st_select_lex_node *end_chain_node)
{
end_chain_node->link_next= *ptr_pos_to_insert;
(*ptr_pos_to_insert)->link_prev= &end_chain_node->link_next;
this->link_prev= ptr_pos_to_insert;
return this;
}
/*
Detach the node from its master and attach it to a new master
*/
void st_select_lex_node::move_as_slave(st_select_lex_node *new_master)
{
exclude_from_tree();
if (new_master->slave)
{
st_select_lex_node *curr= new_master->slave;
for ( ; curr->next ; curr= curr->next) ;
prev= &curr->next;
}
else
prev= &new_master->slave;
*prev= this;
next= 0;
master= new_master;
}
/*
Exclude a node from the tree lex structure, but leave it in the global
list of nodes.
*/
void st_select_lex_node::exclude_from_tree()
{
if ((*prev= next))
next->prev= prev;
}
/*
Exclude select_lex structure (except first (first select can't be
deleted, because it is most upper select))
*/
void st_select_lex_node::exclude()
{
/* exclude from global list */
fast_exclude();
/* exclude from other structures */
exclude_from_tree();
/*
We do not need following statements, because prev pointer of first
list element point to master->slave
if (master->slave == this)
master->slave= next;
*/
}
/*
Exclude level of current unit from tree of SELECTs
SYNOPSYS
st_select_lex_unit::exclude_level()
NOTE: units which belong to current will be brought up on level of
currernt unit
*/
void st_select_lex_unit::exclude_level()
{
SELECT_LEX_UNIT *units= 0, **units_last= &units;
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
// unlink current level from global SELECTs list
if (sl->link_prev && (*sl->link_prev= sl->link_next))
sl->link_next->link_prev= sl->link_prev;
// bring up underlay levels
SELECT_LEX_UNIT **last= 0;
for (SELECT_LEX_UNIT *u= sl->first_inner_unit(); u; u= u->next_unit())
{
u->master= master;
last= (SELECT_LEX_UNIT**)&(u->next);
}
if (last)
{
(*units_last)= sl->first_inner_unit();
units_last= last;
}
}
if (units)
{
// include brought up levels in place of current
(*prev)= units;
(*units_last)= (SELECT_LEX_UNIT*)next;
if (next)
next->prev= (SELECT_LEX_NODE**)units_last;
units->prev= prev;
}
else
{
// exclude currect unit from list of nodes
(*prev)= next;
if (next)
next->prev= prev;
}
// Mark it excluded
prev= NULL;
}
#if 0
/*
Exclude subtree of current unit from tree of SELECTs
SYNOPSYS
st_select_lex_unit::exclude_tree()
*/
void st_select_lex_unit::exclude_tree()
{
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
// unlink current level from global SELECTs list
if (sl->link_prev && (*sl->link_prev= sl->link_next))
sl->link_next->link_prev= sl->link_prev;
// unlink underlay levels
for (SELECT_LEX_UNIT *u= sl->first_inner_unit(); u; u= u->next_unit())
{
u->exclude_level();
}
}
// exclude currect unit from list of nodes
(*prev)= next;
if (next)
next->prev= prev;
}
#endif
/*
st_select_lex_node::mark_as_dependent mark all st_select_lex struct from
this to 'last' as dependent
SYNOPSIS
last - pointer to last st_select_lex struct, before which all
st_select_lex have to be marked as dependent
NOTE
'last' should be reachable from this st_select_lex_node
*/
bool st_select_lex::mark_as_dependent(THD *thd, st_select_lex *last,
Item *dependency)
{
DBUG_ASSERT(this != last);
/*
Mark all selects from resolved to 1 before select where was
found table as depended (of select where was found table)
*/
SELECT_LEX *s= this;
do
{
if (!(s->uncacheable & UNCACHEABLE_DEPENDENT_GENERATED))
{
// Select is dependent of outer select
s->uncacheable= (s->uncacheable & ~UNCACHEABLE_UNITED) |
UNCACHEABLE_DEPENDENT_GENERATED;
SELECT_LEX_UNIT *munit= s->master_unit();
munit->uncacheable= (munit->uncacheable & ~UNCACHEABLE_UNITED) |
UNCACHEABLE_DEPENDENT_GENERATED;
for (SELECT_LEX *sl= munit->first_select(); sl ; sl= sl->next_select())
{
if (sl != s &&
!(sl->uncacheable & (UNCACHEABLE_DEPENDENT_GENERATED |
UNCACHEABLE_UNITED)))
sl->uncacheable|= UNCACHEABLE_UNITED;
}
}
Item_subselect *subquery_expr= s->master_unit()->item;
if (subquery_expr && subquery_expr->mark_as_dependent(thd, last,
dependency))
return TRUE;
} while ((s= s->outer_select()) != last && s != 0);
is_correlated= TRUE;
this->master_unit()->item->is_correlated= TRUE;
return FALSE;
}
bool st_select_lex_node::inc_in_sum_expr() { return 1; }
uint st_select_lex_node::get_in_sum_expr() { return 0; }
TABLE_LIST* st_select_lex_node::get_table_list() { return 0; }
List<Item>* st_select_lex_node::get_item_list() { return 0; }
TABLE_LIST *st_select_lex_node::add_table_to_list(THD *thd, Table_ident *table,
LEX_STRING *alias,
ulong table_join_options,
thr_lock_type flags,
enum_mdl_type mdl_type,
List<Index_hint> *hints,
List<String> *partition_names,
LEX_STRING *option)
{
return 0;
}
ulong st_select_lex_node::get_table_join_options()
{
return 0;
}
/*
prohibit using LIMIT clause
*/
bool st_select_lex::test_limit()
{
if (select_limit != 0)
{
my_error(ER_NOT_SUPPORTED_YET, MYF(0),
"LIMIT & IN/ALL/ANY/SOME subquery");
return(1);
}
return(0);
}
st_select_lex* st_select_lex_unit::outer_select()
{
return (st_select_lex*) master;
}
ha_rows st_select_lex::get_offset()
{
ulonglong val= 0;
if (offset_limit)
{
// see comment for st_select_lex::get_limit()
bool fix_fields_successful= true;
if (!offset_limit->fixed)
{
fix_fields_successful= !offset_limit->fix_fields(master_unit()->thd,
NULL);
DBUG_ASSERT(fix_fields_successful);
}
val= fix_fields_successful ? offset_limit->val_uint() : HA_POS_ERROR;
}
return (ha_rows)val;
}
ha_rows st_select_lex::get_limit()
{
ulonglong val= HA_POS_ERROR;
if (select_limit)
{
/*
fix_fields() has not been called for select_limit. That's due to the
historical reasons -- this item could be only of type Item_int, and
Item_int does not require fix_fields(). Thus, fix_fields() was never
called for select_limit.
Some time ago, Item_splocal was also allowed for LIMIT / OFFSET clauses.
However, the fix_fields() behavior was not updated, which led to a crash
in some cases.
There is no single place where to call fix_fields() for LIMIT / OFFSET
items during the fix-fields-phase. Thus, for the sake of readability,
it was decided to do it here, on the evaluation phase (which is a
violation of design, but we chose the lesser of two evils).
We can call fix_fields() here, because select_limit can be of two
types only: Item_int and Item_splocal. Item_int::fix_fields() is trivial,
and Item_splocal::fix_fields() (or rather Item_sp_variable::fix_fields())
has the following properties:
1) it does not affect other items;
2) it does not fail.
Nevertheless DBUG_ASSERT was added to catch future changes in
fix_fields() implementation. Also added runtime check against a result
of fix_fields() in order to handle error condition in non-debug build.
*/
bool fix_fields_successful= true;
if (!select_limit->fixed)
{
fix_fields_successful= !select_limit->fix_fields(master_unit()->thd,
NULL);
DBUG_ASSERT(fix_fields_successful);
}
val= fix_fields_successful ? select_limit->val_uint() : HA_POS_ERROR;
}
return (ha_rows)val;
}
bool st_select_lex::add_order_to_list(THD *thd, Item *item, bool asc)
{
return add_to_list(thd, order_list, item, asc);
}
bool st_select_lex::add_gorder_to_list(THD *thd, Item *item, bool asc)
{
return add_to_list(thd, gorder_list, item, asc);
}
bool st_select_lex::add_item_to_list(THD *thd, Item *item)
{
DBUG_ENTER("st_select_lex::add_item_to_list");
DBUG_PRINT("info", ("Item: %p", item));
DBUG_RETURN(item_list.push_back(item, thd->mem_root));
}
bool st_select_lex::add_group_to_list(THD *thd, Item *item, bool asc)
{
return add_to_list(thd, group_list, item, asc);
}
bool st_select_lex::add_ftfunc_to_list(THD *thd, Item_func_match *func)
{
return !func || ftfunc_list->push_back(func, thd->mem_root); // end of memory?
}
st_select_lex* st_select_lex::outer_select()
{
return (st_select_lex*) master->get_master();
}
bool st_select_lex::inc_in_sum_expr()
{
in_sum_expr++;
return 0;
}
uint st_select_lex::get_in_sum_expr()
{
return in_sum_expr;
}
TABLE_LIST* st_select_lex::get_table_list()
{
return table_list.first;
}
List<Item>* st_select_lex::get_item_list()
{
return &item_list;
}
ulong st_select_lex::get_table_join_options()
{
return table_join_options;
}
bool st_select_lex::setup_ref_array(THD *thd, uint order_group_num)
{
if (!((options & SELECT_DISTINCT) && !group_list.elements))
hidden_bit_fields= 0;
// find_order_in_list() may need some extra space, so multiply by two.
order_group_num*= 2;
/*
We have to create array in prepared statement memory if it is a
prepared statement
*/
Query_arena *arena= thd->stmt_arena;
const uint n_elems= (n_sum_items +
n_child_sum_items +
item_list.elements +
select_n_reserved +
select_n_having_items +
select_n_where_fields +
order_group_num +
hidden_bit_fields +
fields_in_window_functions) * 5;
if (!ref_pointer_array.is_null())
{
/*
We need to take 'n_sum_items' into account when allocating the array,
and this may actually increase during the optimization phase due to
MIN/MAX rewrite in Item_in_subselect::single_value_transformer.
In the usual case we can reuse the array from the prepare phase.
If we need a bigger array, we must allocate a new one.
*/
if (ref_pointer_array.size() >= n_elems)
return false;
}
Item **array= static_cast<Item**>(arena->alloc(sizeof(Item*) * n_elems));
if (array != NULL)
ref_pointer_array= Ref_ptr_array(array, n_elems);
return array == NULL;
}
void st_select_lex_unit::print(String *str, enum_query_type query_type)
{
bool union_all= !union_distinct;
if (with_clause)
with_clause->print(str, query_type);
for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
{
if (sl != first_select())
{
str->append(STRING_WITH_LEN(" union "));
if (union_all)
str->append(STRING_WITH_LEN("all "));
else if (union_distinct == sl)
union_all= TRUE;
}
if (sl->braces)
str->append('(');
sl->print(thd, str, query_type);
if (sl->braces)
str->append(')');
}
if (fake_select_lex)
{
if (fake_select_lex->order_list.elements)
{
str->append(STRING_WITH_LEN(" order by "));
fake_select_lex->print_order(str,
fake_select_lex->order_list.first,
query_type);
}
fake_select_lex->print_limit(thd, str, query_type);
}
else if (saved_fake_select_lex)
saved_fake_select_lex->print_limit(thd, str, query_type);
}
void st_select_lex::print_order(String *str,
ORDER *order,
enum_query_type query_type)
{
for (; order; order= order->next)
{
if (order->counter_used)
{
char buffer[20];
size_t length= my_snprintf(buffer, 20, "%d", order->counter);
str->append(buffer, (uint) length);
}
else
{
/* replace numeric reference with equivalent for ORDER constant */
if (order->item[0]->type() == Item::INT_ITEM &&
order->item[0]->basic_const_item())
{
/* make it expression instead of integer constant */
str->append(STRING_WITH_LEN("''"));
}
else
(*order->item)->print(str, query_type);
}
if (order->direction == ORDER::ORDER_DESC)
str->append(STRING_WITH_LEN(" desc"));
if (order->next)
str->append(',');
}
}
void st_select_lex::print_limit(THD *thd,
String *str,
enum_query_type query_type)
{
SELECT_LEX_UNIT *unit= master_unit();
Item_subselect *item= unit->item;
if (item && unit->global_parameters() == this)
{
Item_subselect::subs_type subs_type= item->substype();
if (subs_type == Item_subselect::IN_SUBS ||
subs_type == Item_subselect::ALL_SUBS)
{
return;
}
}
if (explicit_limit && select_limit)
{
str->append(STRING_WITH_LEN(" limit "));
if (offset_limit)
{
offset_limit->print(str, query_type);
str->append(',');
}
select_limit->print(str, query_type);
}
}
/**
@brief Restore the LEX and THD in case of a parse error.
This is a clean up call that is invoked by the Bison generated
parser before returning an error from MYSQLparse. If your
semantic actions manipulate with the global thread state (which
is a very bad practice and should not normally be employed) and
need a clean-up in case of error, and you can not use %destructor
rule in the grammar file itself, this function should be used
to implement the clean up.
*/
void LEX::cleanup_lex_after_parse_error(THD *thd)
{
/*
Delete sphead for the side effect of restoring of the original
LEX state, thd->lex, thd->mem_root and thd->free_list if they
were replaced when parsing stored procedure statements. We
will never use sphead object after a parse error, so it's okay
to delete it only for the sake of the side effect.
TODO: make this functionality explicit in sp_head class.
Sic: we must nullify the member of the main lex, not the
current one that will be thrown away
*/
if (thd->lex->sphead)
{
thd->lex->sphead->restore_thd_mem_root(thd);
sp_head::destroy(thd->lex->sphead);
thd->lex->sphead= NULL;
}
}
/*
Initialize (or reset) Query_tables_list object.
SYNOPSIS
reset_query_tables_list()
init TRUE - we should perform full initialization of object with
allocating needed memory
FALSE - object is already initialized so we should only reset
its state so it can be used for parsing/processing
of new statement
DESCRIPTION
This method initializes Query_tables_list so it can be used as part
of LEX object for parsing/processing of statement. One can also use
this method to reset state of already initialized Query_tables_list
so it can be used for processing of new statement.
*/
void Query_tables_list::reset_query_tables_list(bool init)
{
sql_command= SQLCOM_END;
if (!init && query_tables)
{
TABLE_LIST *table= query_tables;
for (;;)
{
delete table->view;
if (query_tables_last == &table->next_global ||
!(table= table->next_global))
break;
}
}
query_tables= 0;
query_tables_last= &query_tables;
query_tables_own_last= 0;
if (init)
{
/*
We delay real initialization of hash (and therefore related
memory allocation) until first insertion into this hash.
*/
my_hash_clear(&sroutines);
}
else if (sroutines.records)
{
/* Non-zero sroutines.records means that hash was initialized. */
my_hash_reset(&sroutines);
}
sroutines_list.empty();
sroutines_list_own_last= sroutines_list.next;
sroutines_list_own_elements= 0;
binlog_stmt_flags= 0;
stmt_accessed_table_flag= 0;
}
/*
Destroy Query_tables_list object with freeing all resources used by it.
SYNOPSIS
destroy_query_tables_list()
*/
void Query_tables_list::destroy_query_tables_list()
{
my_hash_free(&sroutines);
}
/*
Initialize LEX object.
SYNOPSIS
LEX::LEX()
NOTE
LEX object initialized with this constructor can be used as part of
THD object for which one can safely call open_tables(), lock_tables()
and close_thread_tables() functions. But it is not yet ready for
statement parsing. On should use lex_start() function to prepare LEX
for this.
*/
LEX::LEX()
: explain(NULL),
result(0), arena_for_set_stmt(0), mem_root_for_set_stmt(0),
option_type(OPT_DEFAULT), context_analysis_only(0), sphead(0),
is_lex_started(0), limit_rows_examined_cnt(ULONGLONG_MAX)
{
init_dynamic_array2(&plugins, sizeof(plugin_ref), plugins_static_buffer,
INITIAL_LEX_PLUGIN_LIST_SIZE,
INITIAL_LEX_PLUGIN_LIST_SIZE, 0);
reset_query_tables_list(TRUE);
mi.init();
init_dynamic_array2(&delete_gtid_domain, sizeof(uint32),
gtid_domain_static_buffer,
initial_gtid_domain_buffer_size,
initial_gtid_domain_buffer_size, 0);
}
/*
Check whether the merging algorithm can be used on this VIEW
SYNOPSIS
LEX::can_be_merged()
DESCRIPTION
We can apply merge algorithm if it is single SELECT view with
subqueries only in WHERE clause (we do not count SELECTs of underlying
views, and second level subqueries) and we have not grpouping, ordering,
HAVING clause, aggregate functions, DISTINCT clause, LIMIT clause and
several underlying tables.
RETURN
FALSE - only temporary table algorithm can be used
TRUE - merge algorithm can be used
*/
bool LEX::can_be_merged()
{
// TODO: do not forget implement case when select_lex.table_list.elements==0
/* find non VIEW subqueries/unions */
bool selects_allow_merge= (select_lex.next_select() == 0 &&
!(select_lex.uncacheable &
UNCACHEABLE_RAND));
if (selects_allow_merge)
{
for (SELECT_LEX_UNIT *tmp_unit= select_lex.first_inner_unit();
tmp_unit;
tmp_unit= tmp_unit->next_unit())
{
if (tmp_unit->first_select()->parent_lex == this &&
(tmp_unit->item != 0 &&
(tmp_unit->item->place() != IN_WHERE &&
tmp_unit->item->place() != IN_ON &&
tmp_unit->item->place() != SELECT_LIST)))
{
selects_allow_merge= 0;
break;
}
}
}
return (selects_allow_merge &&
select_lex.group_list.elements == 0 &&
select_lex.having == 0 &&
select_lex.with_sum_func == 0 &&
select_lex.table_list.elements >= 1 &&
!(select_lex.options & SELECT_DISTINCT) &&
select_lex.select_limit == 0);
}
/*
check if command can use VIEW with MERGE algorithm (for top VIEWs)
SYNOPSIS
LEX::can_use_merged()
DESCRIPTION
Only listed here commands can use merge algorithm in top level
SELECT_LEX (for subqueries will be used merge algorithm if
LEX::can_not_use_merged() is not TRUE).
RETURN
FALSE - command can't use merged VIEWs
TRUE - VIEWs with MERGE algorithms can be used
*/
bool LEX::can_use_merged()
{
switch (sql_command)
{
case SQLCOM_SELECT:
case SQLCOM_CREATE_TABLE:
case SQLCOM_UPDATE:
case SQLCOM_UPDATE_MULTI:
case SQLCOM_DELETE:
case SQLCOM_DELETE_MULTI:
case SQLCOM_INSERT:
case SQLCOM_INSERT_SELECT:
case SQLCOM_REPLACE:
case SQLCOM_REPLACE_SELECT:
case SQLCOM_LOAD:
return TRUE;
default:
return FALSE;
}
}
/*
Check if command can't use merged views in any part of command
SYNOPSIS
LEX::can_not_use_merged()
DESCRIPTION
Temporary table algorithm will be used on all SELECT levels for queries
listed here (see also LEX::can_use_merged()).
RETURN
FALSE - command can't use merged VIEWs
TRUE - VIEWs with MERGE algorithms can be used
*/
bool LEX::can_not_use_merged()
{
switch (sql_command)
{
case SQLCOM_CREATE_VIEW:
case SQLCOM_SHOW_CREATE:
/*
SQLCOM_SHOW_FIELDS is necessary to make
information schema tables working correctly with views.
see get_schema_tables_result function
*/
case SQLCOM_SHOW_FIELDS:
return TRUE;
default:
return FALSE;
}
}
/*
Detect that we need only table structure of derived table/view
SYNOPSIS
only_view_structure()
RETURN
TRUE yes, we need only structure
FALSE no, we need data
*/
bool LEX::only_view_structure()
{
switch (sql_command) {
case SQLCOM_SHOW_CREATE:
case SQLCOM_SHOW_TABLES:
case SQLCOM_SHOW_FIELDS:
case SQLCOM_REVOKE_ALL:
case SQLCOM_REVOKE:
case SQLCOM_GRANT:
case SQLCOM_CREATE_VIEW:
return TRUE;
default:
return FALSE;
}
}
/*
Should Items_ident be printed correctly
SYNOPSIS
need_correct_ident()
RETURN
TRUE yes, we need only structure
FALSE no, we need data
*/
bool LEX::need_correct_ident()
{
switch(sql_command)
{
case SQLCOM_SHOW_CREATE:
case SQLCOM_SHOW_TABLES:
case SQLCOM_CREATE_VIEW:
return TRUE;
default:
return FALSE;
}
}
/*
Get effective type of CHECK OPTION for given view
SYNOPSIS
get_effective_with_check()
view given view
NOTE
It have not sense to set CHECK OPTION for SELECT satement or subqueries,
so we do not.
RETURN
VIEW_CHECK_NONE no need CHECK OPTION
VIEW_CHECK_LOCAL CHECK OPTION LOCAL
VIEW_CHECK_CASCADED CHECK OPTION CASCADED
*/
uint8 LEX::get_effective_with_check(TABLE_LIST *view)
{
if (view->select_lex->master_unit() == &unit &&
which_check_option_applicable())
return (uint8)view->with_check;
return VIEW_CHECK_NONE;
}
/**
This method should be called only during parsing.
It is aware of compound statements (stored routine bodies)
and will initialize the destination with the default
database of the stored routine, rather than the default
database of the connection it is parsed in.
E.g. if one has no current database selected, or current database
set to 'bar' and then issues:
CREATE PROCEDURE foo.p1() BEGIN SELECT * FROM t1 END//
t1 is meant to refer to foo.t1, not to bar.t1.
This method is needed to support this rule.
@return TRUE in case of error (parsing should be aborted, FALSE in
case of success
*/
bool
LEX::copy_db_to(char **p_db, size_t *p_db_length) const
{
if (sphead && sphead->m_name.str)
{
DBUG_ASSERT(sphead->m_db.str && sphead->m_db.length);
/*
It is safe to assign the string by-pointer, both sphead and
its statements reside in the same memory root.
*/
*p_db= sphead->m_db.str;
if (p_db_length)
*p_db_length= sphead->m_db.length;
return FALSE;
}
return thd->copy_db_to(p_db, p_db_length);
}
/**
Initialize offset and limit counters.
@param sl SELECT_LEX to get offset and limit from.
*/
void st_select_lex_unit::set_limit(st_select_lex *sl)
{
DBUG_ASSERT(!thd->stmt_arena->is_stmt_prepare());
offset_limit_cnt= sl->get_offset();
select_limit_cnt= sl->get_limit();
if (select_limit_cnt + offset_limit_cnt >= select_limit_cnt)
select_limit_cnt+= offset_limit_cnt;
else
select_limit_cnt= HA_POS_ERROR;
}
/**
Decide if a temporary table is needed for the UNION.
@retval true A temporary table is needed.
@retval false A temporary table is not needed.
*/
bool st_select_lex_unit::union_needs_tmp_table()
{
if (with_element && with_element->is_recursive)
return true;
return union_distinct != NULL ||
global_parameters()->order_list.elements != 0 ||
thd->lex->sql_command == SQLCOM_INSERT_SELECT ||
thd->lex->sql_command == SQLCOM_REPLACE_SELECT;
}
/**
@brief Set the initial purpose of this TABLE_LIST object in the list of used
tables.
We need to track this information on table-by-table basis, since when this
table becomes an element of the pre-locked list, it's impossible to identify
which SQL sub-statement it has been originally used in.
E.g.:
User request: SELECT * FROM t1 WHERE f1();
FUNCTION f1(): DELETE FROM t2; RETURN 1;
BEFORE DELETE trigger on t2: INSERT INTO t3 VALUES (old.a);
For this user request, the pre-locked list will contain t1, t2, t3
table elements, each needed for different DML.
The trigger event map is updated to reflect INSERT, UPDATE, DELETE,
REPLACE, LOAD DATA, CREATE TABLE .. SELECT, CREATE TABLE ..
REPLACE SELECT statements, and additionally ON DUPLICATE KEY UPDATE
clause.
*/
void LEX::set_trg_event_type_for_tables()
{
uint8 new_trg_event_map= 0;
DBUG_ENTER("LEX::set_trg_event_type_for_tables");
/*
Some auxiliary operations
(e.g. GRANT processing) create TABLE_LIST instances outside
the parser. Additionally, some commands (e.g. OPTIMIZE) change
the lock type for a table only after parsing is done. Luckily,
these do not fire triggers and do not need to pre-load them.
For these TABLE_LISTs set_trg_event_type is never called, and
trg_event_map is always empty. That means that the pre-locking
algorithm will ignore triggers defined on these tables, if
any, and the execution will either fail with an assert in
sql_trigger.cc or with an error that a used table was not
pre-locked, in case of a production build.
TODO: this usage pattern creates unnecessary module dependencies
and should be rewritten to go through the parser.
Table list instances created outside the parser in most cases
refer to mysql.* system tables. It is not allowed to have
a trigger on a system table, but keeping track of
initialization provides extra safety in case this limitation
is circumvented.
*/
switch (sql_command) {
case SQLCOM_LOCK_TABLES:
/*
On a LOCK TABLE, all triggers must be pre-loaded for this TABLE_LIST
when opening an associated TABLE.
*/
new_trg_event_map= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_INSERT)) |
static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE)) |
static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
/*
Basic INSERT. If there is an additional ON DUPLIATE KEY UPDATE
clause, it will be handled later in this method.
*/
case SQLCOM_INSERT: /* fall through */
case SQLCOM_INSERT_SELECT:
/*
LOAD DATA ... INFILE is expected to fire BEFORE/AFTER INSERT
triggers.
If the statement also has REPLACE clause, it will be
handled later in this method.
*/
case SQLCOM_LOAD: /* fall through */
/*
REPLACE is semantically equivalent to INSERT. In case
of a primary or unique key conflict, it deletes the old
record and inserts a new one. So we also may need to
fire ON DELETE triggers. This functionality is handled
later in this method.
*/
case SQLCOM_REPLACE: /* fall through */
case SQLCOM_REPLACE_SELECT:
/*
CREATE TABLE ... SELECT defaults to INSERT if the table or
view already exists. REPLACE option of CREATE TABLE ...
REPLACE SELECT is handled later in this method.
*/
case SQLCOM_CREATE_TABLE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_INSERT));
break;
/* Basic update and multi-update */
case SQLCOM_UPDATE: /* fall through */
case SQLCOM_UPDATE_MULTI:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE));
break;
/* Basic delete and multi-delete */
case SQLCOM_DELETE: /* fall through */
case SQLCOM_DELETE_MULTI:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
default:
break;
}
switch (duplicates) {
case DUP_UPDATE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_UPDATE));
break;
case DUP_REPLACE:
new_trg_event_map|= static_cast<uint8>
(1 << static_cast<int>(TRG_EVENT_DELETE));
break;
case DUP_ERROR:
default:
break;
}
/*
Do not iterate over sub-selects, only the tables in the outermost
SELECT_LEX can be modified, if any.
*/
TABLE_LIST *tables= select_lex.get_table_list();
while (tables)
{
/*
This is a fast check to filter out statements that do
not change data, or tables on the right side, in case of
INSERT .. SELECT, CREATE TABLE .. SELECT and so on.
Here we also filter out OPTIMIZE statement and non-updateable
views, for which lock_type is TL_UNLOCK or TL_READ after
parsing.
*/
if (static_cast<int>(tables->lock_type) >=
static_cast<int>(TL_WRITE_ALLOW_WRITE))
tables->trg_event_map= new_trg_event_map;
tables= tables->next_local;
}
DBUG_VOID_RETURN;
}
/*
Unlink the first table from the global table list and the first table from
outer select (lex->select_lex) local list
SYNOPSIS
unlink_first_table()
link_to_local Set to 1 if caller should link this table to local list
NOTES
We assume that first tables in both lists is the same table or the local
list is empty.
RETURN
0 If 'query_tables' == 0
unlinked table
In this case link_to_local is set.
*/
TABLE_LIST *LEX::unlink_first_table(bool *link_to_local)
{
TABLE_LIST *first;
if ((first= query_tables))
{
/*
Exclude from global table list
*/
if ((query_tables= query_tables->next_global))
query_tables->prev_global= &query_tables;
else
query_tables_last= &query_tables;
first->next_global= 0;
/*
and from local list if it is not empty
*/
if ((*link_to_local= MY_TEST(select_lex.table_list.first)))
{
select_lex.context.table_list=
select_lex.context.first_name_resolution_table= first->next_local;
select_lex.table_list.first= first->next_local;
select_lex.table_list.elements--; //safety
first->next_local= 0;
/*
Ensure that the global list has the same first table as the local
list.
*/
first_lists_tables_same();
}
}
return first;
}
/*
Bring first local table of first most outer select to first place in global
table list
SYNOPSYS
LEX::first_lists_tables_same()
NOTES
In many cases (for example, usual INSERT/DELETE/...) the first table of
main SELECT_LEX have special meaning => check that it is the first table
in global list and re-link to be first in the global list if it is
necessary. We need such re-linking only for queries with sub-queries in
the select list, as only in this case tables of sub-queries will go to
the global list first.
*/
void LEX::first_lists_tables_same()
{
TABLE_LIST *first_table= select_lex.table_list.first;
if (query_tables != first_table && first_table != 0)
{
TABLE_LIST *next;
if (query_tables_last == &first_table->next_global)
query_tables_last= first_table->prev_global;
if (query_tables_own_last == &first_table->next_global)
query_tables_own_last= first_table->prev_global;
if ((next= *first_table->prev_global= first_table->next_global))
next->prev_global= first_table->prev_global;
/* include in new place */
first_table->next_global= query_tables;
/*
We are sure that query_tables is not 0, because first_table was not
first table in the global list => we can use
query_tables->prev_global without check of query_tables
*/
query_tables->prev_global= &first_table->next_global;
first_table->prev_global= &query_tables;
query_tables= first_table;
}
}
/*
Link table back that was unlinked with unlink_first_table()
SYNOPSIS
link_first_table_back()
link_to_local do we need link this table to local
RETURN
global list
*/
void LEX::link_first_table_back(TABLE_LIST *first,
bool link_to_local)
{
if (first)
{
if ((first->next_global= query_tables))
query_tables->prev_global= &first->next_global;
else
query_tables_last= &first->next_global;
query_tables= first;
if (link_to_local)
{
first->next_local= select_lex.table_list.first;
select_lex.context.table_list= first;
select_lex.table_list.first= first;
select_lex.table_list.elements++; //safety
}
}
}
/*
cleanup lex for case when we open table by table for processing
SYNOPSIS
LEX::cleanup_after_one_table_open()
NOTE
This method is mostly responsible for cleaning up of selects lists and
derived tables state. To rollback changes in Query_tables_list one has
to call Query_tables_list::reset_query_tables_list(FALSE).
*/
void LEX::cleanup_after_one_table_open()
{
/*
thd->lex->derived_tables & additional units may be set if we open
a view. It is necessary to clear thd->lex->derived_tables flag
to prevent processing of derived tables during next open_and_lock_tables
if next table is a real table and cleanup & remove underlying units
NOTE: all units will be connected to thd->lex->select_lex, because we
have not UNION on most upper level.
*/
if (all_selects_list != &select_lex)
{
derived_tables= 0;
select_lex.exclude_from_table_unique_test= false;
/* cleunup underlying units (units of VIEW) */
for (SELECT_LEX_UNIT *un= select_lex.first_inner_unit();
un;
un= un->next_unit())
un->cleanup();
/* reduce all selects list to default state */
all_selects_list= &select_lex;
/* remove underlying units (units of VIEW) subtree */
select_lex.cut_subtree();
}
}
/*
Save current state of Query_tables_list for this LEX, and prepare it
for processing of new statemnt.
SYNOPSIS
reset_n_backup_query_tables_list()
backup Pointer to Query_tables_list instance to be used for backup
*/
void LEX::reset_n_backup_query_tables_list(Query_tables_list *backup)
{
backup->set_query_tables_list(this);
/*
We have to perform full initialization here since otherwise we
will damage backed up state.
*/
this->reset_query_tables_list(TRUE);
}
/*
Restore state of Query_tables_list for this LEX from backup.
SYNOPSIS
restore_backup_query_tables_list()
backup Pointer to Query_tables_list instance used for backup
*/
void LEX::restore_backup_query_tables_list(Query_tables_list *backup)
{
this->destroy_query_tables_list();
this->set_query_tables_list(backup);
}
/*
Checks for usage of routines and/or tables in a parsed statement
SYNOPSIS
LEX:table_or_sp_used()
RETURN
FALSE No routines and tables used
TRUE Either or both routines and tables are used.
*/
bool LEX::table_or_sp_used()
{
DBUG_ENTER("table_or_sp_used");
if (sroutines.records || query_tables)
DBUG_RETURN(TRUE);
DBUG_RETURN(FALSE);
}
/*
Do end-of-prepare fixup for list of tables and their merge-VIEWed tables
SYNOPSIS
fix_prepare_info_in_table_list()
thd Thread handle
tbl List of tables to process
DESCRIPTION
Perform end-end-of prepare fixup for list of tables, if any of the tables
is a merge-algorithm VIEW, recursively fix up its underlying tables as
well.
*/
static void fix_prepare_info_in_table_list(THD *thd, TABLE_LIST *tbl)
{
for (; tbl; tbl= tbl->next_local)
{
if (tbl->on_expr && !tbl->prep_on_expr)
{
thd->check_and_register_item_tree(&tbl->prep_on_expr, &tbl->on_expr);
tbl->on_expr= tbl->on_expr->copy_andor_structure(thd);
}
if (tbl->is_view_or_derived() && tbl->is_merged_derived())
{
SELECT_LEX *sel= tbl->get_single_select();
fix_prepare_info_in_table_list(thd, sel->get_table_list());
}
}
}
/*
Save WHERE/HAVING/ON clauses and replace them with disposable copies
SYNOPSIS
st_select_lex::fix_prepare_information
thd thread handler
conds in/out pointer to WHERE condition to be met at execution
having_conds in/out pointer to HAVING condition to be met at execution
DESCRIPTION
The passed WHERE and HAVING are to be saved for the future executions.
This function saves it, and returns a copy which can be thrashed during
this execution of the statement. By saving/thrashing here we mean only
We also save the chain of ORDER::next in group_list, in case
the list is modified by remove_const().
AND/OR trees.
The function also calls fix_prepare_info_in_table_list that saves all
ON expressions.
*/
void st_select_lex::fix_prepare_information(THD *thd, Item **conds,
Item **having_conds)
{
DBUG_ENTER("st_select_lex::fix_prepare_information");
if (!thd->stmt_arena->is_conventional() &&
!(changed_elements & TOUCHED_SEL_COND))
{
changed_elements|= TOUCHED_SEL_COND;
if (group_list.first)
{
if (!group_list_ptrs)
{
void *mem= thd->stmt_arena->alloc(sizeof(Group_list_ptrs));
group_list_ptrs= new (mem) Group_list_ptrs(thd->stmt_arena->mem_root);
}
group_list_ptrs->reserve(group_list.elements);
for (ORDER *order= group_list.first; order; order= order->next)
{
group_list_ptrs->push_back(order);
}
}
if (*conds)
{
thd->check_and_register_item_tree(&prep_where, conds);
*conds= where= prep_where->copy_andor_structure(thd);
}
if (*having_conds)
{
thd->check_and_register_item_tree(&prep_having, having_conds);
*having_conds= having= prep_having->copy_andor_structure(thd);
}
fix_prepare_info_in_table_list(thd, table_list.first);
}
DBUG_VOID_RETURN;
}
/*
There are st_select_lex::add_table_to_list &
st_select_lex::set_lock_for_tables are in sql_parse.cc
st_select_lex::print is in sql_select.cc
st_select_lex_unit::prepare, st_select_lex_unit::exec,
st_select_lex_unit::cleanup, st_select_lex_unit::reinit_exec_mechanism,
st_select_lex_unit::change_result
are in sql_union.cc
*/
/*
Sets the kind of hints to be added by the calls to add_index_hint().
SYNOPSIS
set_index_hint_type()
type_arg The kind of hints to be added from now on.
clause The clause to use for hints to be added from now on.
DESCRIPTION
Used in filling up the tagged hints list.
This list is filled by first setting the kind of the hint as a
context variable and then adding hints of the current kind.
Then the context variable index_hint_type can be reset to the
next hint type.
*/
void st_select_lex::set_index_hint_type(enum index_hint_type type_arg,
index_clause_map clause)
{
current_index_hint_type= type_arg;
current_index_hint_clause= clause;
}
/*
Makes an array to store index usage hints (ADD/FORCE/IGNORE INDEX).
SYNOPSIS
alloc_index_hints()
thd current thread.
*/
void st_select_lex::alloc_index_hints (THD *thd)
{
index_hints= new (thd->mem_root) List<Index_hint>();
}
/*
adds an element to the array storing index usage hints
(ADD/FORCE/IGNORE INDEX).
SYNOPSIS
add_index_hint()
thd current thread.
str name of the index.
length number of characters in str.
RETURN VALUE
0 on success, non-zero otherwise
*/
bool st_select_lex::add_index_hint (THD *thd, char *str, uint length)
{
return index_hints->push_front(new (thd->mem_root)
Index_hint(current_index_hint_type,
current_index_hint_clause,
str, length), thd->mem_root);
}
/**
Optimize all subqueries that have not been flattened into semi-joins.
@details
This functionality is a method of SELECT_LEX instead of JOIN because
SQL statements as DELETE/UPDATE do not have a corresponding JOIN object.
@see JOIN::optimize_unflattened_subqueries
@param const_only Restrict subquery optimization to constant subqueries
@return Operation status
@retval FALSE success.
@retval TRUE error occurred.
*/
bool st_select_lex::optimize_unflattened_subqueries(bool const_only)
{
SELECT_LEX_UNIT *next_unit= NULL;
for (SELECT_LEX_UNIT *un= first_inner_unit();
un;
un= next_unit ? next_unit : un->next_unit())
{
Item_subselect *subquery_predicate= un->item;
next_unit= NULL;
if (subquery_predicate)
{
if (!subquery_predicate->fixed)
{
/*
This subquery was excluded as part of some expression so it is
invisible from all prepared expression.
*/
next_unit= un->next_unit();
un->exclude_level();
if (next_unit)
continue;
break;
}
if (subquery_predicate->substype() == Item_subselect::IN_SUBS)
{
Item_in_subselect *in_subs= (Item_in_subselect*) subquery_predicate;
if (in_subs->is_jtbm_merged)
continue;
}
if (const_only && !subquery_predicate->const_item())
{
/* Skip non-constant subqueries if the caller asked so. */
continue;
}
bool empty_union_result= true;
bool is_correlated_unit= false;
bool first= true;
bool union_plan_saved= false;
/*
If the subquery is a UNION, optimize all the subqueries in the UNION. If
there is no UNION, then the loop will execute once for the subquery.
*/
for (SELECT_LEX *sl= un->first_select(); sl; sl= sl->next_select())
{
JOIN *inner_join= sl->join;
if (first)
first= false;
else
{
if (!union_plan_saved)
{
union_plan_saved= true;
if (un->save_union_explain(un->thd->lex->explain))
return true; /* Failure */
}
}
if (!inner_join)
continue;
SELECT_LEX *save_select= un->thd->lex->current_select;
ulonglong save_options;
int res;
/* We need only 1 row to determine existence */
un->set_limit(un->global_parameters());
un->thd->lex->current_select= sl;
save_options= inner_join->select_options;
if (options & SELECT_DESCRIBE)
{
/* Optimize the subquery in the context of EXPLAIN. */
sl->set_explain_type(FALSE);
sl->options|= SELECT_DESCRIBE;
inner_join->select_options|= SELECT_DESCRIBE;
}
if ((res= inner_join->optimize()))
return TRUE;
if (!inner_join->cleaned)
sl->update_used_tables();
sl->update_correlated_cache();
is_correlated_unit|= sl->is_correlated;
inner_join->select_options= save_options;
un->thd->lex->current_select= save_select;
Explain_query *eq;
if ((eq= inner_join->thd->lex->explain))
{
Explain_select *expl_sel;
if ((expl_sel= eq->get_select(inner_join->select_lex->select_number)))
{
sl->set_explain_type(TRUE);
expl_sel->select_type= sl->type;
}
}
if (empty_union_result)
{
/*
If at least one subquery in a union is non-empty, the UNION result
is non-empty. If there is no UNION, the only subquery is non-empy.
*/
empty_union_result= inner_join->empty_result();
}
if (res)
return TRUE;
}
if (empty_union_result)
subquery_predicate->no_rows_in_result();
if (!is_correlated_unit)
un->uncacheable&= ~UNCACHEABLE_DEPENDENT;
subquery_predicate->is_correlated= is_correlated_unit;
}
}
return FALSE;
}
/**
@brief Process all derived tables/views of the SELECT.
@param lex LEX of this thread
@param phase phases to run derived tables/views through
@details
This function runs specified 'phases' on all tables from the
table_list of this select.
@return FALSE ok.
@return TRUE an error occur.
*/
bool st_select_lex::handle_derived(LEX *lex, uint phases)
{
return lex->handle_list_of_derived(table_list.first, phases);
}
/**
@brief
Returns first unoccupied table map and table number
@param map [out] return found map
@param tablenr [out] return found tablenr
@details
Returns first unoccupied table map and table number in this select.
Map and table are returned in *'map' and *'tablenr' accordingly.
@retrun TRUE no free table map/table number
@return FALSE found free table map/table number
*/
bool st_select_lex::get_free_table_map(table_map *map, uint *tablenr)
{
*map= 0;
*tablenr= 0;
TABLE_LIST *tl;
List_iterator<TABLE_LIST> ti(leaf_tables);
while ((tl= ti++))
{
if (tl->table->map > *map)
*map= tl->table->map;
if (tl->table->tablenr > *tablenr)
*tablenr= tl->table->tablenr;
}
(*map)<<= 1;
(*tablenr)++;
if (*tablenr >= MAX_TABLES)
return TRUE;
return FALSE;
}
/**
@brief
Append given table to the leaf_tables list.
@param link Offset to which list in table structure to use
@param table Table to append
@details
Append given 'table' to the leaf_tables list using the 'link' offset.
If the 'table' is linked with other tables through next_leaf/next_local
chains then whole list will be appended.
*/
void st_select_lex::append_table_to_list(TABLE_LIST *TABLE_LIST::*link,
TABLE_LIST *table)
{
TABLE_LIST *tl;
for (tl= leaf_tables.head(); tl->*link; tl= tl->*link) ;
tl->*link= table;
}
/*
@brief
Replace given table from the leaf_tables list for a list of tables
@param table Table to replace
@param list List to substititute the table for
@details
Replace 'table' from the leaf_tables list for a list of tables 'tbl_list'.
*/
void st_select_lex::replace_leaf_table(TABLE_LIST *table, List<TABLE_LIST> &tbl_list)
{
TABLE_LIST *tl;
List_iterator<TABLE_LIST> ti(leaf_tables);
while ((tl= ti++))
{
if (tl == table)
{
ti.replace(tbl_list);
break;
}
}
}
/**
@brief
Assigns new table maps to tables in the leaf_tables list
@param derived Derived table to take initial table map from
@param map table map to begin with
@param tablenr table number to begin with
@param parent_lex new parent select_lex
@details
Assign new table maps/table numbers to all tables in the leaf_tables list.
'map'/'tablenr' are used for the first table and shifted to left/
increased for each consequent table in the leaf_tables list.
If the 'derived' table is given then it's table map/number is used for the
first table in the list and 'map'/'tablenr' are used for the second and
all consequent tables.
The 'parent_lex' is set as the new parent select_lex for all tables in the
list.
*/
void st_select_lex::remap_tables(TABLE_LIST *derived, table_map map,
uint tablenr, SELECT_LEX *parent_lex)
{
bool first_table= TRUE;
TABLE_LIST *tl;
table_map first_map;
uint first_tablenr;
if (derived && derived->table)
{
first_map= derived->table->map;
first_tablenr= derived->table->tablenr;
}
else
{
first_map= map;
map<<= 1;
first_tablenr= tablenr++;
}
/*
Assign table bit/table number.
To the first table of the subselect the table bit/tablenr of the
derived table is assigned. The rest of tables are getting bits
sequentially, starting from the provided table map/tablenr.
*/
List_iterator<TABLE_LIST> ti(leaf_tables);
while ((tl= ti++))
{
if (first_table)
{
first_table= FALSE;
tl->table->set_table_map(first_map, first_tablenr);
}
else
{
tl->table->set_table_map(map, tablenr);
tablenr++;
map<<= 1;
}
SELECT_LEX *old_sl= tl->select_lex;
tl->select_lex= parent_lex;
for(TABLE_LIST *emb= tl->embedding;
emb && emb->select_lex == old_sl;
emb= emb->embedding)
emb->select_lex= parent_lex;
}
}
/**
@brief
Merge a subquery into this select.
@param derived derived table of the subquery to be merged
@param subq_select select_lex of the subquery
@param map table map for assigning to merged tables from subquery
@param table_no table number for assigning to merged tables from subquery
@details
This function merges a subquery into its parent select. In short the
merge operation appends the subquery FROM table list to the parent's
FROM table list. In more details:
.) the top_join_list of the subquery is wrapped into a join_nest
and attached to 'derived'
.) subquery's leaf_tables list is merged with the leaf_tables
list of this select_lex
.) the table maps and table numbers of the tables merged from
the subquery are adjusted to reflect their new binding to
this select
@return TRUE an error occur
@return FALSE ok
*/
bool SELECT_LEX::merge_subquery(THD *thd, TABLE_LIST *derived,
SELECT_LEX *subq_select,
uint table_no, table_map map)
{
derived->wrap_into_nested_join(subq_select->top_join_list);
ftfunc_list->append(subq_select->ftfunc_list);
if (join ||
thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
thd->lex->sql_command == SQLCOM_DELETE_MULTI)
{
List_iterator_fast<Item_in_subselect> li(subq_select->sj_subselects);
Item_in_subselect *in_subq;
while ((in_subq= li++))
{
sj_subselects.push_back(in_subq, thd->mem_root);
if (in_subq->emb_on_expr_nest == NO_JOIN_NEST)
in_subq->emb_on_expr_nest= derived;
}
}
/* Walk through child's tables and adjust table map, tablenr,
* parent_lex */
subq_select->remap_tables(derived, map, table_no, this);
subq_select->merged_into= this;
replace_leaf_table(derived, subq_select->leaf_tables);
return FALSE;
}
/**
@brief
Mark tables from the leaf_tables list as belong to a derived table.
@param derived tables will be marked as belonging to this derived
@details
Run through the leaf_list and mark all tables as belonging to the 'derived'.
*/
void SELECT_LEX::mark_as_belong_to_derived(TABLE_LIST *derived)
{
/* Mark tables as belonging to this DT */
TABLE_LIST *tl;
List_iterator<TABLE_LIST> ti(leaf_tables);
while ((tl= ti++))
tl->belong_to_derived= derived;
}
/**
@brief
Update used_tables cache for this select
@details
This function updates used_tables cache of ON expressions of all tables
in the leaf_tables list and of the conds expression (if any).
*/
void SELECT_LEX::update_used_tables()
{
TABLE_LIST *tl;
List_iterator<TABLE_LIST> ti(leaf_tables);
while ((tl= ti++))
{
if (tl->table && !tl->is_view_or_derived())
{
TABLE_LIST *embedding= tl->embedding;
for (embedding= tl->embedding; embedding; embedding=embedding->embedding)
{
if (embedding->is_view_or_derived())
{
DBUG_ASSERT(embedding->is_merged_derived());
TABLE *tab= tl->table;
tab->covering_keys= tab->s->keys_for_keyread;
tab->covering_keys.intersect(tab->keys_in_use_for_query);
/*
View/derived was merged. Need to recalculate read_set/vcol_set
bitmaps here. For example:
CREATE VIEW v1 AS SELECT f1,f2,f3 FROM t1;
SELECT f1 FROM v1;
Initially, the view definition will put all f1,f2,f3 in the
read_set for t1. But after the view is merged, only f1 should
be in the read_set.
*/
bitmap_clear_all(tab->read_set);
if (tab->vcol_set)
bitmap_clear_all(tab->vcol_set);
break;
}
}
}
}
ti.rewind();
while ((tl= ti++))
{
TABLE_LIST *embedding= tl;
do
{
bool maybe_null;
if ((maybe_null= MY_TEST(embedding->outer_join)))
{
tl->table->maybe_null= maybe_null;
break;
}
}
while ((embedding= embedding->embedding));
if (tl->on_expr)
{
tl->on_expr->update_used_tables();
tl->on_expr->walk(&Item::eval_not_null_tables, 0, NULL);
}
/*
- There is no need to check sj_on_expr, because merged semi-joins inject
sj_on_expr into the parent's WHERE clase.
- For non-merged semi-joins (aka JTBMs), we need to check their
left_expr. There is no need to check the rest of the subselect, we know
it is uncorrelated and so cannot refer to any tables in this select.
*/
if (tl->jtbm_subselect)
{
Item *left_expr= tl->jtbm_subselect->left_expr;
left_expr->walk(&Item::update_table_bitmaps_processor, FALSE, NULL);
}
embedding= tl->embedding;
while (embedding)
{
if (embedding->on_expr &&
embedding->nested_join->join_list.head() == tl)
{
embedding->on_expr->update_used_tables();
embedding->on_expr->walk(&Item::eval_not_null_tables, 0, NULL);
}
tl= embedding;
embedding= tl->embedding;
}
}
if (join->conds)
{
join->conds->update_used_tables();
join->conds->walk(&Item::eval_not_null_tables, 0, NULL);
}
if (join->having)
{
join->having->update_used_tables();
}
Item *item;
List_iterator_fast<Item> it(join->all_fields);
select_list_tables= 0;
while ((item= it++))
{
item->update_used_tables();
select_list_tables|= item->used_tables();
}
Item_outer_ref *ref;
List_iterator_fast<Item_outer_ref> ref_it(inner_refs_list);
while ((ref= ref_it++))
{
item= ref->outer_ref;
item->update_used_tables();
}
for (ORDER *order= group_list.first; order; order= order->next)
(*order->item)->update_used_tables();
if (!master_unit()->is_union() || master_unit()->global_parameters() != this)
{
for (ORDER *order= order_list.first; order; order= order->next)
(*order->item)->update_used_tables();
}
join->result->update_used_tables();
}
/**
@brief
Update is_correlated cache for this select
@details
*/
void st_select_lex::update_correlated_cache()
{
TABLE_LIST *tl;
List_iterator<TABLE_LIST> ti(leaf_tables);
is_correlated= false;
while ((tl= ti++))
{
// is_correlated|= tl->is_with_table_recursive_reference();
if (tl->on_expr)
is_correlated|= MY_TEST(tl->on_expr->used_tables() & OUTER_REF_TABLE_BIT);
for (TABLE_LIST *embedding= tl->embedding ; embedding ;
embedding= embedding->embedding)
{
if (embedding->on_expr)
is_correlated|= MY_TEST(embedding->on_expr->used_tables() &
OUTER_REF_TABLE_BIT);
}
}
if (join->conds)
is_correlated|= MY_TEST(join->conds->used_tables() & OUTER_REF_TABLE_BIT);
is_correlated|= join->having_is_correlated;
if (join->having)
is_correlated|= MY_TEST(join->having->used_tables() & OUTER_REF_TABLE_BIT);
if (join->tmp_having)
is_correlated|= MY_TEST(join->tmp_having->used_tables() &
OUTER_REF_TABLE_BIT);
Item *item;
List_iterator_fast<Item> it(join->fields_list);
while ((item= it++))
is_correlated|= MY_TEST(item->used_tables() & OUTER_REF_TABLE_BIT);
for (ORDER *order= group_list.first; order; order= order->next)
is_correlated|= MY_TEST((*order->item)->used_tables() &
OUTER_REF_TABLE_BIT);
if (!master_unit()->is_union())
{
for (ORDER *order= order_list.first; order; order= order->next)
is_correlated|= MY_TEST((*order->item)->used_tables() &
OUTER_REF_TABLE_BIT);
}
if (!is_correlated)
uncacheable&= ~UNCACHEABLE_DEPENDENT;
}
/**
Set the EXPLAIN type for this subquery.
@param on_the_fly TRUE<=> We're running a SHOW EXPLAIN command, so we must
not change any variables
*/
void st_select_lex::set_explain_type(bool on_the_fly)
{
bool is_primary= FALSE;
if (next_select())
is_primary= TRUE;
if (!is_primary && first_inner_unit())
{
/*
If there is at least one materialized derived|view then it's a PRIMARY select.
Otherwise, all derived tables/views were merged and this select is a SIMPLE one.
*/
for (SELECT_LEX_UNIT *un= first_inner_unit(); un; un= un->next_unit())
{
if ((!un->derived || un->derived->is_materialized_derived()))
{
is_primary= TRUE;
break;
}
}
}
if (on_the_fly && !is_primary && have_merged_subqueries)
is_primary= TRUE;
SELECT_LEX *first= master_unit()->first_select();
/* drop UNCACHEABLE_EXPLAIN, because it is for internal usage only */
uint8 is_uncacheable= (uncacheable & ~UNCACHEABLE_EXPLAIN);
bool using_materialization= FALSE;
Item_subselect *parent_item;
if ((parent_item= master_unit()->item) &&
parent_item->substype() == Item_subselect::IN_SUBS)
{
Item_in_subselect *in_subs= (Item_in_subselect*)parent_item;
/*
Surprisingly, in_subs->is_set_strategy() can return FALSE here,
even for the last invocation of this function for the select.
*/
if (in_subs->test_strategy(SUBS_MATERIALIZATION))
using_materialization= TRUE;
}
if (&master_unit()->thd->lex->select_lex == this)
{
type= is_primary ? "PRIMARY" : "SIMPLE";
}
else
{
if (this == first)
{
/* If we're a direct child of a UNION, we're the first sibling there */
if (linkage == DERIVED_TABLE_TYPE)
type= "DERIVED";
else if (using_materialization)
type= "MATERIALIZED";
else
{
if (is_uncacheable & UNCACHEABLE_DEPENDENT)
type= "DEPENDENT SUBQUERY";
else
{
type= is_uncacheable? "UNCACHEABLE SUBQUERY" :
"SUBQUERY";
}
}
}
else
{
/* This a non-first sibling in UNION */
if (is_uncacheable & UNCACHEABLE_DEPENDENT)
type= "DEPENDENT UNION";
else if (using_materialization)
type= "MATERIALIZED UNION";
else
{
type= is_uncacheable ? "UNCACHEABLE UNION": "UNION";
if (this == master_unit()->fake_select_lex)
type= "UNION RESULT";
/*
join below may be =NULL when this functions is called at an early
stage. It will be later called again and we will set the correct
value.
*/
if (join)
{
bool uses_cte= false;
for (JOIN_TAB *tab= first_linear_tab(join, WITHOUT_BUSH_ROOTS,
WITH_CONST_TABLES);
tab;
tab= next_linear_tab(join, tab, WITHOUT_BUSH_ROOTS))
{
/*
pos_in_table_list=NULL for e.g. post-join aggregation JOIN_TABs.
*/
if (!(tab->table && tab->table->pos_in_table_list))
continue;
TABLE_LIST *tbl= tab->table->pos_in_table_list;
if (tbl->with && tbl->with->is_recursive &&
tbl->is_with_table_recursive_reference())
{
uses_cte= true;
break;
}
}
if (uses_cte)
type= "RECURSIVE UNION";
}
}
}
}
if (!on_the_fly)
options|= SELECT_DESCRIBE;
}
/**
@brief
Increase estimated number of records for a derived table/view
@param records number of records to increase estimate by
@details
This function increases estimated number of records by the 'records'
for the derived table to which this select belongs to.
*/
void SELECT_LEX::increase_derived_records(ha_rows records)
{
SELECT_LEX_UNIT *unit= master_unit();
DBUG_ASSERT(unit->derived);
if (unit->with_element && unit->with_element->is_recursive)
{
st_select_lex *first_recursive= unit->with_element->first_recursive;
st_select_lex *sl= unit->first_select();
for ( ; sl != first_recursive; sl= sl->next_select())
{
if (sl == this)
break;
}
if (sl == first_recursive)
return;
}
select_union *result= (select_union*)unit->result;
if (HA_ROWS_MAX - records > result->records)
result->records+= records;
else
result->records= HA_ROWS_MAX;
}
/**
@brief
Mark select's derived table as a const one.
@param empty Whether select has an empty result set
@details
Mark derived table/view of this select as a constant one (to
materialize it at the optimization phase) unless this select belongs to a
union. Estimated number of rows is incremented if this select has non empty
result set.
*/
void SELECT_LEX::mark_const_derived(bool empty)
{
TABLE_LIST *derived= master_unit()->derived;
/* join == NULL in DELETE ... RETURNING */
if (!(join && join->thd->lex->describe) && derived)
{
if (!empty)
increase_derived_records(1);
if (!master_unit()->is_union() && !derived->is_merged_derived())
derived->fill_me= TRUE;
}
}
bool st_select_lex::save_leaf_tables(THD *thd)
{
Query_arena *arena, backup;
arena= thd->activate_stmt_arena_if_needed(&backup);
List_iterator_fast<TABLE_LIST> li(leaf_tables);
TABLE_LIST *table;
while ((table= li++))
{
if (leaf_tables_exec.push_back(table, thd->mem_root))
return 1;
table->tablenr_exec= table->get_tablenr();
table->map_exec= table->get_map();
if (join && (join->select_options & SELECT_DESCRIBE))
table->maybe_null_exec= 0;
else
table->maybe_null_exec= table->table? table->table->maybe_null: 0;
}
if (arena)
thd->restore_active_arena(arena, &backup);
return 0;
}
bool LEX::save_prep_leaf_tables()
{
if (!thd->save_prep_leaf_list)
return FALSE;
Query_arena *arena= thd->stmt_arena, backup;
arena= thd->activate_stmt_arena_if_needed(&backup);
//It is used for DETETE/UPDATE so top level has only one SELECT
DBUG_ASSERT(select_lex.next_select() == NULL);
bool res= select_lex.save_prep_leaf_tables(thd);
if (arena)
thd->restore_active_arena(arena, &backup);
if (res)
return TRUE;
thd->save_prep_leaf_list= FALSE;
return FALSE;
}
bool st_select_lex::save_prep_leaf_tables(THD *thd)
{
List_iterator_fast<TABLE_LIST> li(leaf_tables);
TABLE_LIST *table;
/*
Check that the SELECT_LEX was really prepared and so tables are setup.
It can be subquery in SET clause of UPDATE which was not prepared yet, so
its tables are not yet setup and ready for storing.
*/
if (prep_leaf_list_state != READY)
return FALSE;
while ((table= li++))
{
if (leaf_tables_prep.push_back(table))
return TRUE;
}
prep_leaf_list_state= SAVED;
for (SELECT_LEX_UNIT *u= first_inner_unit(); u; u= u->next_unit())
{
for (SELECT_LEX *sl= u->first_select(); sl; sl= sl->next_select())
{
if (sl->save_prep_leaf_tables(thd))
return TRUE;
}
}
return FALSE;
}
/*
Return true if this select_lex has been converted into a semi-join nest
within 'ancestor'.
We need a loop to check this because there could be several nested
subselects, like
SELECT ... FROM grand_parent
WHERE expr1 IN (SELECT ... FROM parent
WHERE expr2 IN ( SELECT ... FROM child)
which were converted into:
SELECT ...
FROM grand_parent SEMI_JOIN (parent JOIN child)
WHERE
expr1 AND expr2
In this case, both parent and child selects were merged into the parent.
*/
bool st_select_lex::is_merged_child_of(st_select_lex *ancestor)
{
bool all_merged= TRUE;
for (SELECT_LEX *sl= this; sl && sl!=ancestor;
sl=sl->outer_select())
{
Item *subs= sl->master_unit()->item;
if (subs && subs->type() == Item::SUBSELECT_ITEM &&
((Item_subselect*)subs)->substype() == Item_subselect::IN_SUBS &&
((Item_in_subselect*)subs)->test_strategy(SUBS_SEMI_JOIN))
{
continue;
}
if (sl->master_unit()->derived &&
sl->master_unit()->derived->is_merged_derived())
{
continue;
}
all_merged= FALSE;
break;
}
return all_merged;
}
/*
This is used by SHOW EXPLAIN. It assuses query plan has been already
collected into QPF structures and we only need to print it out.
*/
int LEX::print_explain(select_result_sink *output, uint8 explain_flags,
bool is_analyze, bool *printed_anything)
{
int res;
if (explain && explain->have_query_plan())
{
res= explain->print_explain(output, explain_flags, is_analyze);
*printed_anything= true;
}
else
{
res= 0;
*printed_anything= false;
}
return res;
}
/**
Allocates and set arena for SET STATEMENT old values.
@param backup where to save backup of arena.
@retval 1 Error
@retval 0 OK
*/
bool LEX::set_arena_for_set_stmt(Query_arena *backup)
{
DBUG_ENTER("LEX::set_arena_for_set_stmt");
DBUG_ASSERT(arena_for_set_stmt== 0);
if (!mem_root_for_set_stmt)
{
mem_root_for_set_stmt= new MEM_ROOT();
if (!(mem_root_for_set_stmt))
DBUG_RETURN(1);
init_sql_alloc(mem_root_for_set_stmt, ALLOC_ROOT_SET, ALLOC_ROOT_SET,
MYF(MY_THREAD_SPECIFIC));
}
if (!(arena_for_set_stmt= new(mem_root_for_set_stmt)
Query_arena_memroot(mem_root_for_set_stmt,
Query_arena::STMT_INITIALIZED)))
DBUG_RETURN(1);
DBUG_PRINT("info", ("mem_root: %p arena: %p",
mem_root_for_set_stmt,
arena_for_set_stmt));
thd->set_n_backup_active_arena(arena_for_set_stmt, backup);
DBUG_RETURN(0);
}
void LEX::reset_arena_for_set_stmt(Query_arena *backup)
{
DBUG_ENTER("LEX::reset_arena_for_set_stmt");
DBUG_ASSERT(arena_for_set_stmt);
thd->restore_active_arena(arena_for_set_stmt, backup);
DBUG_PRINT("info", ("mem_root: %p arena: %p",
arena_for_set_stmt->mem_root,
arena_for_set_stmt));
DBUG_VOID_RETURN;
}
void LEX::free_arena_for_set_stmt()
{
DBUG_ENTER("LEX::free_arena_for_set_stmt");
if (!arena_for_set_stmt)
return;
DBUG_PRINT("info", ("mem_root: %p arena: %p",
arena_for_set_stmt->mem_root,
arena_for_set_stmt));
arena_for_set_stmt->free_items();
delete(arena_for_set_stmt);
free_root(mem_root_for_set_stmt, MYF(MY_KEEP_PREALLOC));
arena_for_set_stmt= 0;
DBUG_VOID_RETURN;
}
void LEX::restore_set_statement_var()
{
DBUG_ENTER("LEX::restore_set_statement_var");
if (!old_var_list.is_empty())
{
DBUG_PRINT("info", ("vars: %d", old_var_list.elements));
sql_set_variables(thd, &old_var_list, false);
old_var_list.empty();
free_arena_for_set_stmt();
}
DBUG_ASSERT(!is_arena_for_set_stmt());
DBUG_VOID_RETURN;
}
/*
Save explain structures of a UNION. The only variable member is whether the
union has "Using filesort".
There is also save_union_explain_part2() function, which is called before we read
UNION's output.
The reason for it is examples like this:
SELECT col1 FROM t1 UNION SELECT col2 FROM t2 ORDER BY (select ... from t3 ...)
Here, the (select ... from t3 ...) subquery must be a child of UNION's
st_select_lex. However, it is not connected as child until a very late
stage in execution.
*/
int st_select_lex_unit::save_union_explain(Explain_query *output)
{
SELECT_LEX *first= first_select();
if (output->get_union(first->select_number))
return 0; /* Already added */
Explain_union *eu=
new (output->mem_root) Explain_union(output->mem_root,
thd->lex->analyze_stmt);
if (with_element && with_element->is_recursive)
eu->is_recursive_cte= true;
if (derived)
eu->connection_type= Explain_node::EXPLAIN_NODE_DERIVED;
/*
Note: Non-merged semi-joins cannot be made out of UNIONs currently, so we
dont ever set EXPLAIN_NODE_NON_MERGED_SJ.
*/
for (SELECT_LEX *sl= first; sl; sl= sl->next_select())
eu->add_select(sl->select_number);
eu->fake_select_type= "UNION RESULT";
eu->using_filesort= MY_TEST(global_parameters()->order_list.first);
eu->using_tmp= union_needs_tmp_table();
// Save the UNION node
output->add_node(eu);
if (eu->get_select_id() == 1)
output->query_plan_ready();
return 0;
}
/*
@see st_select_lex_unit::save_union_explain
*/
int st_select_lex_unit::save_union_explain_part2(Explain_query *output)
{
Explain_union *eu= output->get_union(first_select()->select_number);
if (fake_select_lex)
{
for (SELECT_LEX_UNIT *unit= fake_select_lex->first_inner_unit();
unit; unit= unit->next_unit())
{
if (!(unit->item && unit->item->eliminated))
{
eu->add_child(unit->first_select()->select_number);
}
}
fake_select_lex->join->explain= &eu->fake_select_lex_explain;
}
return 0;
}
/**
A routine used by the parser to decide whether we are specifying a full
partitioning or if only partitions to add or to split.
@note This needs to be outside of WITH_PARTITION_STORAGE_ENGINE since it
is used from the sql parser that doesn't have any ifdef's
@retval TRUE Yes, it is part of a management partition command
@retval FALSE No, not a management partition command
*/
bool LEX::is_partition_management() const
{
return (sql_command == SQLCOM_ALTER_TABLE &&
(alter_info.flags == Alter_info::ALTER_ADD_PARTITION ||
alter_info.flags == Alter_info::ALTER_REORGANIZE_PARTITION));
}
#ifdef MYSQL_SERVER
uint binlog_unsafe_map[256];
#define UNSAFE(a, b, c) \
{ \
DBUG_PRINT("unsafe_mixed_statement", ("SETTING BASE VALUES: %s, %s, %02X\n", \
LEX::stmt_accessed_table_string(a), \
LEX::stmt_accessed_table_string(b), \
c)); \
unsafe_mixed_statement(a, b, c); \
}
/*
Sets the combination given by "a" and "b" and automatically combinations
given by other types of access, i.e. 2^(8 - 2), as unsafe.
It may happen a colision when automatically defining a combination as unsafe.
For that reason, a combination has its unsafe condition redefined only when
the new_condition is greater then the old. For instance,
. (BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY) is never overwritten by
. (BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF).
*/
void unsafe_mixed_statement(LEX::enum_stmt_accessed_table a,
LEX::enum_stmt_accessed_table b, uint condition)
{
int type= 0;
int index= (1U << a) | (1U << b);
for (type= 0; type < 256; type++)
{
if ((type & index) == index)
{
binlog_unsafe_map[type] |= condition;
}
}
}
/*
The BINLOG_* AND TRX_CACHE_* values can be combined by using '&' or '|',
which means that both conditions need to be satisfied or any of them is
enough. For example,
. BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY means that the statment is
unsafe when the option is on and trx-cache is not empty;
. BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF means the statement is unsafe
in all cases.
. TRX_CACHE_EMPTY | TRX_CACHE_NOT_EMPTY means the statement is unsafe
in all cases. Similar as above.
*/
void binlog_unsafe_map_init()
{
memset((void*) binlog_unsafe_map, 0, sizeof(uint) * 256);
/*
Classify a statement as unsafe when there is a mixed statement and an
on-going transaction at any point of the execution if:
1. The mixed statement is about to update a transactional table and
a non-transactional table.
2. The mixed statement is about to update a transactional table and
read from a non-transactional table.
3. The mixed statement is about to update a non-transactional table
and temporary transactional table.
4. The mixed statement is about to update a temporary transactional
table and read from a non-transactional table.
5. The mixed statement is about to update a transactional table and
a temporary non-transactional table.
6. The mixed statement is about to update a transactional table and
read from a temporary non-transactional table.
7. The mixed statement is about to update a temporary transactional
table and temporary non-transactional table.
8. The mixed statement is about to update a temporary transactional
table and read from a temporary non-transactional table.
After updating a transactional table if:
9. The mixed statement is about to update a non-transactional table
and read from a transactional table.
10. The mixed statement is about to update a non-transactional table
and read from a temporary transactional table.
11. The mixed statement is about to update a temporary non-transactional
table and read from a transactional table.
12. The mixed statement is about to update a temporary non-transactional
table and read from a temporary transactional table.
13. The mixed statement is about to update a temporary non-transactional
table and read from a non-transactional table.
The reason for this is that locks acquired may not protected a concurrent
transaction of interfering in the current execution and by consequence in
the result.
*/
/* Case 1. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_WRITES_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 2. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 3. */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_WRITES_TEMP_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 4. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF);
/* Case 5. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 6. */
UNSAFE(LEX::STMT_WRITES_TRANS_TABLE, LEX::STMT_READS_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 7. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 8. */
UNSAFE(LEX::STMT_WRITES_TEMP_TRANS_TABLE, LEX::STMT_READS_TEMP_NON_TRANS_TABLE,
BINLOG_DIRECT_ON);
/* Case 9. */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_READS_TRANS_TABLE,
(BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF) & TRX_CACHE_NOT_EMPTY);
/* Case 10 */
UNSAFE(LEX::STMT_WRITES_NON_TRANS_TABLE, LEX::STMT_READS_TEMP_TRANS_TABLE,
(BINLOG_DIRECT_ON | BINLOG_DIRECT_OFF) & TRX_CACHE_NOT_EMPTY);
/* Case 11. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_TRANS_TABLE,
BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY);
/* Case 12. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_TEMP_TRANS_TABLE,
BINLOG_DIRECT_ON & TRX_CACHE_NOT_EMPTY);
/* Case 13. */
UNSAFE(LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE, LEX::STMT_READS_NON_TRANS_TABLE,
BINLOG_DIRECT_OFF & TRX_CACHE_NOT_EMPTY);
}
#endif
/**
@brief
Finding fiels that are used in the GROUP BY of this st_select_lex
@param thd The thread handle
@details
This method looks through the fields which are used in the GROUP BY of this
st_select_lex and saves this fields.
*/
void st_select_lex::collect_grouping_fields(THD *thd)
{
grouping_tmp_fields.empty();
List_iterator<Item> li(join->fields_list);
Item *item= li++;
for (uint i= 0; i < master_unit()->derived->table->s->fields; i++, (item=li++))
{
for (ORDER *ord= join->group_list; ord; ord= ord->next)
{
if ((*ord->item)->eq((Item*)item, 0))
{
Grouping_tmp_field *grouping_tmp_field=
new Grouping_tmp_field(master_unit()->derived->table->field[i], item);
grouping_tmp_fields.push_back(grouping_tmp_field);
}
}
}
}
/**
@brief
For a condition check possibility of exraction a formula over grouping fields
@param cond The condition whose subformulas are to be analyzed
@details
This method traverses the AND-OR condition cond and for each subformula of
the condition it checks whether it can be usable for the extraction of a
condition over the grouping fields of this select. The method uses
the call-back parameter check_processor to ckeck whether a primary formula
depends only on grouping fields.
The subformulas that are not usable are marked with the flag NO_EXTRACTION_FL.
The subformulas that can be entierly extracted are marked with the flag
FULL_EXTRACTION_FL.
@note
This method is called before any call of extract_cond_for_grouping_fields.
The flag NO_EXTRACTION_FL set in a subformula allows to avoid building clone
for the subformula when extracting the pushable condition.
The flag FULL_EXTRACTION_FL allows to delete later all top level conjuncts
from cond.
*/
void
st_select_lex::check_cond_extraction_for_grouping_fields(Item *cond,
TABLE_LIST *derived)
{
cond->clear_extraction_flag();
if (cond->type() == Item::COND_ITEM)
{
bool and_cond= ((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC;
List<Item> *arg_list= ((Item_cond*) cond)->argument_list();
List_iterator<Item> li(*arg_list);
uint count= 0; // to count items not containing NO_EXTRACTION_FL
uint count_full= 0; // to count items with FULL_EXTRACTION_FL
Item *item;
while ((item=li++))
{
check_cond_extraction_for_grouping_fields(item, derived);
if (item->get_extraction_flag() != NO_EXTRACTION_FL)
{
count++;
if (item->get_extraction_flag() == FULL_EXTRACTION_FL)
count_full++;
}
else if (!and_cond)
break;
}
if ((and_cond && count == 0) || item)
cond->set_extraction_flag(NO_EXTRACTION_FL);
if (count_full == arg_list->elements)
cond->set_extraction_flag(FULL_EXTRACTION_FL);
if (cond->get_extraction_flag() != 0)
{
li.rewind();
while ((item=li++))
item->clear_extraction_flag();
}
}
else
{
int fl= cond->excl_dep_on_grouping_fields(this) ?
FULL_EXTRACTION_FL : NO_EXTRACTION_FL;
cond->set_extraction_flag(fl);
}
}
/**
@brief
Build condition extractable from the given one depended on grouping fields
@param thd The thread handle
@param cond The condition from which the condition depended
on grouping fields is to be extracted
@param no_top_clones If it's true then no clones for the top fully
extractable conjuncts are built
@details
For the given condition cond this method finds out what condition depended
only on the grouping fields can be extracted from cond. If such condition C
exists the method builds the item for it.
This method uses the flags NO_EXTRACTION_FL and FULL_EXTRACTION_FL set by the
preliminary call of st_select_lex::check_cond_extraction_for_grouping_fields
to figure out whether a subformula depends only on these fields or not.
@note
The built condition C is always implied by the condition cond
(cond => C). The method tries to build the most restictive such
condition (i.e. for any other condition C' such that cond => C'
we have C => C').
@note
The build item is not ready for usage: substitution for the field items
has to be done and it has to be re-fixed.
@retval
the built condition depended only on grouping fields if such a condition exists
NULL if there is no such a condition
*/
Item *st_select_lex::build_cond_for_grouping_fields(THD *thd, Item *cond,
bool no_top_clones)
{
if (cond->get_extraction_flag() == FULL_EXTRACTION_FL)
{
if (no_top_clones)
return cond;
cond->clear_extraction_flag();
return cond->build_clone(thd, thd->mem_root);
}
if (cond->type() == Item::COND_ITEM)
{
bool cond_and= false;
Item_cond *new_cond;
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
{
cond_and= true;
new_cond= new (thd->mem_root) Item_cond_and(thd);
}
else
new_cond= new (thd->mem_root) Item_cond_or(thd);
if (!new_cond)
return 0;
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
if (item->get_extraction_flag() == NO_EXTRACTION_FL)
{
DBUG_ASSERT(cond_and);
item->clear_extraction_flag();
continue;
}
Item *fix= build_cond_for_grouping_fields(thd, item,
no_top_clones & cond_and);
if (!fix)
{
if (cond_and)
continue;
break;
}
new_cond->argument_list()->push_back(fix, thd->mem_root);
}
if (!cond_and && item)
{
while((item= li++))
item->clear_extraction_flag();
return 0;
}
switch (new_cond->argument_list()->elements)
{
case 0:
return 0;
case 1:
return new_cond->argument_list()->head();
default:
return new_cond;
}
}
return 0;
}
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