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mariadb/sql/sql_alter.cc
Michael Widenius 7ffc9da093 Implementation of MDEV-5491: CREATE OR REPLACE TABLE 
Using CREATE OR REPLACE TABLE is be identical to

DROP TABLE IF EXISTS table_name;
CREATE TABLE ...;

Except that:

* CREATE OR REPLACE is be atomic (now one can create the same table between drop and create).
* Temporary tables will not shadow the table name for the DROP as the CREATE TABLE tells us already if we are using a temporary table or not.
* If the table was locked with LOCK TABLES, the new table will be locked with the same lock after it's created.

Implementation details:
- We don't anymore open the to-be-created table during CREATE TABLE, which the original code did.
  - There is no need to open a table we are planning to create. It's enough to check if the table exists or not.
- Removed some of duplicated code for CREATE IF NOT EXISTS.
- Give an error when using CREATE OR REPLACE with IF NOT EXISTS (conflicting options).
- As a side effect of the code changes, we don't anymore have to internally re-prepare prepared statements with CREATE TABLE if the table exists.
- Made one code path for all testing if log table are in use.
- Better error message if one tries to create/drop/alter a log table in use
- Added back disabled rpl_row_create_table test as it now seams to work and includes a lot of interesting tests.
- Added HA_LEX_CREATE_REPLACE to mark if we are using CREATE OR REPLACE
- Aligned CREATE OR REPLACE parsing code in sql_yacc.yy for TABLE and VIEW
- Changed interface for drop_temporary_table() to make it more reusable
- Changed Locked_tables_list::init_locked_tables() to work on the table object instead of the table list object. Before this it used a mix of both, which was not good.
- Locked_tables_list::unlock_locked_tables(THD *thd) now requires a valid thd argument. Old usage of calling this with 0 i changed to instead call Locked_tables_list::reset()
- Added functions Locked_tables_list:restore_lock() and Locked_tables_list::add_back_last_deleted_lock() to be able to easily add back a locked table to the lock list.
- Added restart_trans_for_tables() to be able to restart a transaction.
- DROP_ACL is required if one uses CREATE TABLE OR REPLACE.
- Added drop of normal and temporary tables in create_table_imp() if CREATE OR REPLACE was used.
- Added reacquiring of table locks in mysql_create_table() and mysql_create_like_table()




mysql-test/include/commit.inc:
  With new code we get fewer status increments
mysql-test/r/commit_1innodb.result:
  With new code we get fewer status increments
mysql-test/r/create.result:
  Added testing of create or replace with timeout
mysql-test/r/create_or_replace.result:
  Basic testing of CREATE OR REPLACE TABLE
mysql-test/r/partition_exchange.result:
  New error message
mysql-test/r/ps_ddl.result:
  Fewer reprepares with new code
mysql-test/suite/archive/discover.result:
  Don't rediscover archive tables if the .frm file exists
  (Sergei will look at this if there is a better way...)
mysql-test/suite/archive/discover.test:
  Don't rediscover archive tables if the .frm file exists
  (Sergei will look at this if there is a better way...)
mysql-test/suite/funcs_1/r/innodb_views.result:
  New error message
mysql-test/suite/funcs_1/r/memory_views.result:
  New error message
mysql-test/suite/rpl/disabled.def:
  rpl_row_create_table should now be safe to use
mysql-test/suite/rpl/r/rpl_row_create_table.result:
  Updated results after adding back disabled test
mysql-test/suite/rpl/t/rpl_create_if_not_exists.test:
  Added comment
mysql-test/suite/rpl/t/rpl_row_create_table.test:
  Added CREATE OR REPLACE TABLE test
mysql-test/t/create.test:
  Added CREATE OR REPLACE TABLE test
mysql-test/t/create_or_replace-master.opt:
  Create logs
mysql-test/t/create_or_replace.test:
  Basic testing of CREATE OR REPLACE TABLE
mysql-test/t/partition_exchange.test:
  Error number changed as we are now using same code for all log table change issues
mysql-test/t/ps_ddl.test:
  Fewer reprepares with new code
sql/handler.h:
  Moved things around a bit in a structure to get better alignment.
  Added HA_LEX_CREATE_REPLACE to mark if we are using CREATE OR REPLACE
  Added 3 elements to end of HA_CREATE_INFO to be able to store state to add backs locks in case of LOCK TABLES.
sql/log.cc:
  Reimplemented check_if_log_table():
  - Simpler and faster usage
  - Can give error messages
  
  This gives us one code path for allmost all error messages if log tables are in use
sql/log.h:
  New interface for check_if_log_table()
sql/slave.cc:
  More logging
sql/sql_alter.cc:
  New interface for check_if_log_table()
sql/sql_base.cc:
  More documentation
  Changed interface for drop_temporary_table() to make it more reusable
  Changed Locked_tables_list::init_locked_tables() to work on the table object instead of the table list object. Before this it used a mix of both, which was not good.
  Locked_tables_list::unlock_locked_tables(THD *thd) now requires a valid thd argument.  Old usage of calling this with 0 i changed to instead call Locked_tables_list::reset()
  Added functions Locked_tables_list:restore_lock() and Locked_tables_list::add_back_last_deleted_lock() to be able to easily add back a locked table to the lock list.
  Check for command number instead of open_strategy of CREATE TABLE was used.
  Added restart_trans_for_tables() to be able to restart a transaction.  This was needed in "create or replace ... select" between the drop table and the select.
sql/sql_base.h:
  Added and updated function prototypes
sql/sql_class.h:
  Added new prototypes to Locked_tables_list class
  Added extra argument to select_create to avoid double call to eof() or send_error()
  - I needed this in some edge case where the table was not created against expections.
sql/sql_db.cc:
  New interface for check_if_log_table()
sql/sql_insert.cc:
  Remember position to lock information so that we can reaquire table lock for LOCK TABLES + CREATE OR REPLACE TABLE SELECT. Later add back the lock by calling restore_lock().
  Removed one not needed indentation level in create_table_from_items()
  Ensure we don't call send_eof() or abort_result_set() twice.
sql/sql_lex.h:
  Removed variable that I temporarly added in an earlier changeset
sql/sql_parse.cc:
  Removed old test code (marked with QQ)
  Ensure that we have open_strategy set as TABLE_LIST::OPEN_STUB in CREATE TABLE
  Removed some IF NOT EXISTS code as this is now handled in create_table_table_impl().
  Set OPTION_KEEP_LOGS later. This code had to be moved as the test for IF EXISTS has changed place.
  DROP_ACL is required if one uses CREATE TABLE OR REPLACE.
sql/sql_partition_admin.cc:
  New interface for check_if_log_table()
sql/sql_rename.cc:
  New interface for check_if_log_table()
sql/sql_table.cc:
  New interface for check_if_log_table()
  Moved some code in mysql_rm_table() under a common test.
  - Safe as temporary tables doesn't have statistics.
  - !is_temporary_table(table) test was moved out from drop_temporary_table() and merged with upper level code.
  - Added drop of normal and temporary tables in create_table_imp() if CREATE OR REPLACE was used.
  - Added reacquiring of table locks in mysql_create_table() and mysql_create_like_table()
  - In mysql_create_like_table(), restore table->open_strategy() if it was changed.
  - Re-test if table was a view after opening it.
sql/sql_table.h:
  New prototype for mysql_create_table_no_lock()
sql/sql_yacc.yy:
  Added syntax for CREATE OR REPLACE TABLE
  Reuse new code for CREATE OR REPLACE VIEW
sql/table.h:
  Added name for enum type
sql/table_cache.cc:
  More DBUG
2014-01-29 15:37:17 +02:00

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/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
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 02110-1301 USA */
#include "sql_parse.h" // check_access
#include "sql_table.h" // mysql_alter_table,
// mysql_exchange_partition
#include "sql_base.h" // open_temporary_tables
#include "sql_alter.h"
Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
:drop_list(rhs.drop_list, mem_root),
alter_list(rhs.alter_list, mem_root),
key_list(rhs.key_list, mem_root),
create_list(rhs.create_list, mem_root),
flags(rhs.flags),
keys_onoff(rhs.keys_onoff),
partition_names(rhs.partition_names, mem_root),
num_parts(rhs.num_parts),
requested_algorithm(rhs.requested_algorithm),
requested_lock(rhs.requested_lock)
{
/*
Make deep copies of used objects.
This is not a fully deep copy - clone() implementations
of Alter_drop, Alter_column, Key, foreign_key, Key_part_spec
do not copy string constants. At the same length the only
reason we make a copy currently is that ALTER/CREATE TABLE
code changes input Alter_info definitions, but string
constants never change.
*/
list_copy_and_replace_each_value(drop_list, mem_root);
list_copy_and_replace_each_value(alter_list, mem_root);
list_copy_and_replace_each_value(key_list, mem_root);
list_copy_and_replace_each_value(create_list, mem_root);
/* partition_names are not deeply copied currently */
}
bool Alter_info::set_requested_algorithm(const LEX_STRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (!my_strcasecmp(system_charset_info, str->str, "INPLACE"))
requested_algorithm= ALTER_TABLE_ALGORITHM_INPLACE;
else if (!my_strcasecmp(system_charset_info, str->str, "COPY"))
requested_algorithm= ALTER_TABLE_ALGORITHM_COPY;
else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
requested_algorithm= ALTER_TABLE_ALGORITHM_DEFAULT;
else
return true;
return false;
}
bool Alter_info::set_requested_lock(const LEX_STRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (!my_strcasecmp(system_charset_info, str->str, "NONE"))
requested_lock= ALTER_TABLE_LOCK_NONE;
else if (!my_strcasecmp(system_charset_info, str->str, "SHARED"))
requested_lock= ALTER_TABLE_LOCK_SHARED;
else if (!my_strcasecmp(system_charset_info, str->str, "EXCLUSIVE"))
requested_lock= ALTER_TABLE_LOCK_EXCLUSIVE;
else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
requested_lock= ALTER_TABLE_LOCK_DEFAULT;
else
return true;
return false;
}
Alter_table_ctx::Alter_table_ctx()
: datetime_field(NULL), error_if_not_empty(false),
tables_opened(0),
db(NULL), table_name(NULL), alias(NULL),
new_db(NULL), new_name(NULL), new_alias(NULL),
fk_error_if_delete_row(false), fk_error_id(NULL),
fk_error_table(NULL)
#ifndef DBUG_OFF
, tmp_table(false)
#endif
{
}
Alter_table_ctx::Alter_table_ctx(THD *thd, TABLE_LIST *table_list,
uint tables_opened_arg,
char *new_db_arg, char *new_name_arg)
: datetime_field(NULL), error_if_not_empty(false),
tables_opened(tables_opened_arg),
new_db(new_db_arg), new_name(new_name_arg),
fk_error_if_delete_row(false), fk_error_id(NULL),
fk_error_table(NULL)
#ifndef DBUG_OFF
, tmp_table(false)
#endif
{
/*
Assign members db, table_name, new_db and new_name
to simplify further comparisions: we want to see if it's a RENAME
later just by comparing the pointers, avoiding the need for strcmp.
*/
db= table_list->db;
table_name= table_list->table_name;
alias= (lower_case_table_names == 2) ? table_list->alias : table_name;
if (!new_db || !my_strcasecmp(table_alias_charset, new_db, db))
new_db= db;
if (new_name)
{
DBUG_PRINT("info", ("new_db.new_name: '%s'.'%s'", new_db, new_name));
if (lower_case_table_names == 1) // Convert new_name/new_alias to lower case
{
my_casedn_str(files_charset_info, new_name);
new_alias= new_name;
}
else if (lower_case_table_names == 2) // Convert new_name to lower case
{
strmov(new_alias= new_alias_buff, new_name);
my_casedn_str(files_charset_info, new_name);
}
else
new_alias= new_name; // LCTN=0 => case sensitive + case preserving
if (!is_database_changed() &&
!my_strcasecmp(table_alias_charset, new_name, table_name))
{
/*
Source and destination table names are equal:
make is_table_renamed() more efficient.
*/
new_alias= table_name;
new_name= table_name;
}
}
else
{
new_alias= alias;
new_name= table_name;
}
my_snprintf(tmp_name, sizeof(tmp_name), "%s-%lx_%lx", tmp_file_prefix,
current_pid, thd->thread_id);
/* Safety fix for InnoDB */
if (lower_case_table_names)
my_casedn_str(files_charset_info, tmp_name);
if (table_list->table->s->tmp_table == NO_TMP_TABLE)
{
build_table_filename(path, sizeof(path) - 1, db, table_name, "", 0);
build_table_filename(new_path, sizeof(new_path) - 1, new_db, new_name, "", 0);
build_table_filename(new_filename, sizeof(new_filename) - 1,
new_db, new_name, reg_ext, 0);
build_table_filename(tmp_path, sizeof(tmp_path) - 1, new_db, tmp_name, "",
FN_IS_TMP);
}
else
{
/*
We are not filling path, new_path and new_filename members if
we are altering temporary table as these members are not used in
this case. This fact is enforced with assert.
*/
build_tmptable_filename(thd, tmp_path, sizeof(tmp_path));
#ifndef DBUG_OFF
tmp_table= true;
#endif
}
}
bool Sql_cmd_alter_table::execute(THD *thd)
{
LEX *lex= thd->lex;
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= &lex->select_lex;
/* first table of first SELECT_LEX */
TABLE_LIST *first_table= (TABLE_LIST*) select_lex->table_list.first;
/*
Code in mysql_alter_table() may modify its HA_CREATE_INFO argument,
so we have to use a copy of this structure to make execution
prepared statement- safe. A shallow copy is enough as no memory
referenced from this structure will be modified.
@todo move these into constructor...
*/
HA_CREATE_INFO create_info(lex->create_info);
Alter_info alter_info(lex->alter_info, thd->mem_root);
ulong priv=0;
ulong priv_needed= ALTER_ACL;
bool result;
DBUG_ENTER("Sql_cmd_alter_table::execute");
if (thd->is_fatal_error) /* out of memory creating a copy of alter_info */
DBUG_RETURN(TRUE);
/*
We also require DROP priv for ALTER TABLE ... DROP PARTITION, as well
as for RENAME TO, as being done by SQLCOM_RENAME_TABLE
*/
if (alter_info.flags & (Alter_info::ALTER_DROP_PARTITION |
Alter_info::ALTER_RENAME))
priv_needed|= DROP_ACL;
/* Must be set in the parser */
DBUG_ASSERT(select_lex->db);
DBUG_ASSERT(!(alter_info.flags & Alter_info::ALTER_EXCHANGE_PARTITION));
DBUG_ASSERT(!(alter_info.flags & Alter_info::ALTER_ADMIN_PARTITION));
if (check_access(thd, priv_needed, first_table->db,
&first_table->grant.privilege,
&first_table->grant.m_internal,
0, 0) ||
check_access(thd, INSERT_ACL | CREATE_ACL, select_lex->db,
&priv,
NULL, /* Don't use first_tab->grant with sel_lex->db */
0, 0))
DBUG_RETURN(TRUE); /* purecov: inspected */
/* If it is a merge table, check privileges for merge children. */
if (create_info.merge_list.first)
{
/*
The user must have (SELECT_ACL | UPDATE_ACL | DELETE_ACL) on the
underlying base tables, even if there are temporary tables with the same
names.
From user's point of view, it might look as if the user must have these
privileges on temporary tables to create a merge table over them. This is
one of two cases when a set of privileges is required for operations on
temporary tables (see also CREATE TABLE).
The reason for this behavior stems from the following facts:
- For merge tables, the underlying table privileges are checked only
at CREATE TABLE / ALTER TABLE time.
In other words, once a merge table is created, the privileges of
the underlying tables can be revoked, but the user will still have
access to the merge table (provided that the user has privileges on
the merge table itself).
- Temporary tables shadow base tables.
I.e. there might be temporary and base tables with the same name, and
the temporary table takes the precedence in all operations.
- For temporary MERGE tables we do not track if their child tables are
base or temporary. As result we can't guarantee that privilege check
which was done in presence of temporary child will stay relevant later
as this temporary table might be removed.
If SELECT_ACL | UPDATE_ACL | DELETE_ACL privileges were not checked for
the underlying *base* tables, it would create a security breach as in
Bug#12771903.
*/
if (check_table_access(thd, SELECT_ACL | UPDATE_ACL | DELETE_ACL,
create_info.merge_list.first, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE);
}
if (check_grant(thd, priv_needed, first_table, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
if (lex->name.str && !test_all_bits(priv, INSERT_ACL | CREATE_ACL))
{
// Rename of table
TABLE_LIST tmp_table;
memset(&tmp_table, 0, sizeof(tmp_table));
tmp_table.table_name= lex->name.str;
tmp_table.db= select_lex->db;
tmp_table.grant.privilege= priv;
if (check_grant(thd, INSERT_ACL | CREATE_ACL, &tmp_table, FALSE,
UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
}
/* Don't yet allow changing of symlinks with ALTER TABLE */
if (create_info.data_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER(WARN_OPTION_IGNORED),
"DATA DIRECTORY");
if (create_info.index_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER(WARN_OPTION_IGNORED),
"INDEX DIRECTORY");
create_info.data_file_name= create_info.index_file_name= NULL;
thd->enable_slow_log= opt_log_slow_admin_statements;
result= mysql_alter_table(thd, select_lex->db, lex->name.str,
&create_info,
first_table,
&alter_info,
select_lex->order_list.elements,
select_lex->order_list.first,
lex->ignore);
DBUG_RETURN(result);
}
bool Sql_cmd_discard_import_tablespace::execute(THD *thd)
{
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= &thd->lex->select_lex;
/* first table of first SELECT_LEX */
TABLE_LIST *table_list= (TABLE_LIST*) select_lex->table_list.first;
if (check_access(thd, ALTER_ACL, table_list->db,
&table_list->grant.privilege,
&table_list->grant.m_internal,
0, 0))
return true;
if (check_grant(thd, ALTER_ACL, table_list, false, UINT_MAX, false))
return true;
thd->enable_slow_log= opt_log_slow_admin_statements;
/*
Check if we attempt to alter mysql.slow_log or
mysql.general_log table and return an error if
it is the case.
TODO: this design is obsolete and will be removed.
*/
if (check_if_log_table(table_list, TRUE, "ALTER"))
return true;
return
mysql_discard_or_import_tablespace(thd, table_list,
m_tablespace_op == DISCARD_TABLESPACE);
}
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