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mariadb/sql/records.cc
Vladislav Vaintroub 6c279ad6a7 MDEV-15091 : Windows, 64bit: reenable and fix warning C4267 (conversion from 'size_t' to 'type', possible loss of data) 
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.

This fix excludes rocksdb, spider,spider, sphinx and connect for now.
2018-02-06 12:55:58 +00:00

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/*
Copyright (c) 2000, 2010, Oracle and/or its affiliates.
Copyright (c) 2009, 2017, 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 02110-1301 USA */
#ifdef USE_PRAGMA_INTERFACE
#pragma implementation /* gcc class implementation */
#endif
/**
@file
@brief
Functions for easy reading of records, possible through a cache
*/
#include "mariadb.h"
#include "records.h"
#include "sql_priv.h"
#include "records.h"
#include "opt_range.h" // SQL_SELECT
#include "sql_class.h" // THD
#include "sql_base.h"
#include "sql_sort.h" // SORT_ADDON_FIELD
static int rr_quick(READ_RECORD *info);
int rr_sequential(READ_RECORD *info);
static int rr_from_tempfile(READ_RECORD *info);
static int rr_unpack_from_tempfile(READ_RECORD *info);
static int rr_unpack_from_buffer(READ_RECORD *info);
int rr_from_pointers(READ_RECORD *info);
static int rr_from_cache(READ_RECORD *info);
static int init_rr_cache(THD *thd, READ_RECORD *info);
static int rr_cmp(uchar *a,uchar *b);
static int rr_index_first(READ_RECORD *info);
static int rr_index_last(READ_RECORD *info);
static int rr_index(READ_RECORD *info);
static int rr_index_desc(READ_RECORD *info);
/**
Initialize READ_RECORD structure to perform full index scan in desired
direction using read_record.read_record() interface
This function has been added at late stage and is used only by
UPDATE/DELETE. Other statements perform index scans using
join_read_first/next functions.
@param info READ_RECORD structure to initialize.
@param thd Thread handle
@param table Table to be accessed
@param print_error If true, call table->file->print_error() if an error
occurs (except for end-of-records error)
@param idx index to scan
@param reverse Scan in the reverse direction
*/
bool init_read_record_idx(READ_RECORD *info, THD *thd, TABLE *table,
bool print_error, uint idx, bool reverse)
{
int error= 0;
DBUG_ENTER("init_read_record_idx");
empty_record(table);
bzero((char*) info,sizeof(*info));
info->thd= thd;
info->table= table;
info->record= table->record[0];
info->print_error= print_error;
info->unlock_row= rr_unlock_row;
table->status=0; /* And it's always found */
if (!table->file->inited &&
(error= table->file->ha_index_init(idx, 1)))
{
if (print_error)
table->file->print_error(error, MYF(0));
}
/* read_record_func will be changed to rr_index in rr_index_first */
info->read_record_func= reverse ? rr_index_last : rr_index_first;
DBUG_RETURN(error != 0);
}
/*
init_read_record is used to scan by using a number of different methods.
Which method to use is set-up in this call so that later calls to
the info->read_record will call the appropriate method using a function
pointer.
There are five methods that relate completely to the sort function
filesort. The result of a filesort is retrieved using read_record
calls. The other two methods are used for normal table access.
The filesort will produce references to the records sorted, these
references can be stored in memory or in a temporary file.
The temporary file is normally used when the references doesn't fit into
a properly sized memory buffer. For most small queries the references
are stored in the memory buffer.
SYNOPSIS
init_read_record()
info OUT read structure
thd Thread handle
table Table the data [originally] comes from.
select SQL_SELECT structure. We may select->quick or
select->file as data source
use_record_cache Call file->extra_opt(HA_EXTRA_CACHE,...)
if we're going to do sequential read and some
additional conditions are satisfied.
print_error Copy this to info->print_error
disable_rr_cache Don't use rr_from_cache (used by sort-union
index-merge which produces rowid sequences that
are already ordered)
DESCRIPTION
This function sets up reading data via one of the methods:
The temporary file is also used when performing an update where a key is
modified.
Methods used when ref's are in memory (using rr_from_pointers):
rr_unpack_from_buffer:
----------------------
This method is used when table->sort.addon_field is allocated.
This is allocated for most SELECT queries not involving any BLOB's.
In this case the records are fetched from a memory buffer.
rr_from_pointers:
-----------------
Used when the above is not true, UPDATE, DELETE and so forth and
SELECT's involving BLOB's. It is also used when the addon_field
buffer is not allocated due to that its size was bigger than the
session variable max_length_for_sort_data.
In this case the record data is fetched from the handler using the
saved reference using the rnd_pos handler call.
Methods used when ref's are in a temporary file (using rr_from_tempfile)
rr_unpack_from_tempfile:
------------------------
Same as rr_unpack_from_buffer except that references are fetched from
temporary file. Should obviously not really happen other than in
strange configurations.
rr_from_tempfile:
-----------------
Same as rr_from_pointers except that references are fetched from
temporary file instead of from
rr_from_cache:
--------------
This is a special variant of rr_from_tempfile that can be used for
handlers that is not using the HA_FAST_KEY_READ table flag. Instead
of reading the references one by one from the temporary file it reads
a set of them, sorts them and reads all of them into a buffer which
is then used for a number of subsequent calls to rr_from_cache.
It is only used for SELECT queries and a number of other conditions
on table size.
All other accesses use either index access methods (rr_quick) or a full
table scan (rr_sequential).
rr_quick:
---------
rr_quick uses one of the QUICK_SELECT classes in opt_range.cc to
perform an index scan. There are loads of functionality hidden
in these quick classes. It handles all index scans of various kinds.
rr_sequential:
--------------
This is the most basic access method of a table using rnd_init,
rnd_next and rnd_end. No indexes are used.
*/
bool init_read_record(READ_RECORD *info,THD *thd, TABLE *table,
SQL_SELECT *select,
SORT_INFO *filesort,
int use_record_cache, bool print_error,
bool disable_rr_cache)
{
IO_CACHE *tempfile;
SORT_ADDON_FIELD *addon_field= filesort ? filesort->addon_field : 0;
DBUG_ENTER("init_read_record");
bzero((char*) info,sizeof(*info));
info->thd=thd;
info->table=table;
info->forms= &info->table; /* Only one table */
info->addon_field= addon_field;
if ((table->s->tmp_table == INTERNAL_TMP_TABLE ||
table->s->tmp_table == NON_TRANSACTIONAL_TMP_TABLE) &&
!addon_field)
(void) table->file->extra(HA_EXTRA_MMAP);
if (addon_field)
{
info->rec_buf= (uchar*) filesort->addon_buf.str;
info->ref_length= (uint)filesort->addon_buf.length;
info->unpack= filesort->unpack;
}
else
{
empty_record(table);
info->record= table->record[0];
info->ref_length= (uint)table->file->ref_length;
}
info->select=select;
info->print_error=print_error;
info->unlock_row= rr_unlock_row;
info->ignore_not_found_rows= 0;
table->status= 0; /* Rows are always found */
tempfile= 0;
if (select && my_b_inited(&select->file))
tempfile= &select->file;
else if (filesort && my_b_inited(&filesort->io_cache))
tempfile= &filesort->io_cache;
if (tempfile && !(select && select->quick))
{
DBUG_PRINT("info",("using rr_from_tempfile"));
info->read_record_func=
addon_field ? rr_unpack_from_tempfile : rr_from_tempfile;
info->io_cache= tempfile;
reinit_io_cache(info->io_cache,READ_CACHE,0L,0,0);
info->ref_pos=table->file->ref;
if (!table->file->inited)
if (table->file->ha_rnd_init_with_error(0))
DBUG_RETURN(1);
/*
addon_field is checked because if we use addon fields,
it doesn't make sense to use cache - we don't read from the table
and filesort->io_cache is read sequentially
*/
if (!disable_rr_cache &&
!addon_field &&
thd->variables.read_rnd_buff_size &&
!(table->file->ha_table_flags() & HA_FAST_KEY_READ) &&
(table->db_stat & HA_READ_ONLY ||
table->reginfo.lock_type <= TL_READ_NO_INSERT) &&
(ulonglong) table->s->reclength* (table->file->stats.records+
table->file->stats.deleted) >
(ulonglong) MIN_FILE_LENGTH_TO_USE_ROW_CACHE &&
info->io_cache->end_of_file/info->ref_length * table->s->reclength >
(my_off_t) MIN_ROWS_TO_USE_TABLE_CACHE &&
!table->s->blob_fields &&
info->ref_length <= MAX_REFLENGTH)
{
if (! init_rr_cache(thd, info))
{
DBUG_PRINT("info",("using rr_from_cache"));
info->read_record_func= rr_from_cache;
}
}
}
else if (select && select->quick)
{
DBUG_PRINT("info",("using rr_quick"));
info->read_record_func= rr_quick;
}
else if (filesort && filesort->record_pointers)
{
DBUG_PRINT("info",("using record_pointers"));
if (table->file->ha_rnd_init_with_error(0))
DBUG_RETURN(1);
info->cache_pos= filesort->record_pointers;
info->cache_end= (info->cache_pos+
filesort->return_rows * info->ref_length);
info->read_record_func=
addon_field ? rr_unpack_from_buffer : rr_from_pointers;
}
else if (table->file->keyread_enabled())
{
int error;
info->read_record_func= rr_index_first;
if (!table->file->inited &&
(error= table->file->ha_index_init(table->file->keyread, 1)))
{
if (print_error)
table->file->print_error(error, MYF(0));
DBUG_RETURN(1);
}
}
else
{
DBUG_PRINT("info",("using rr_sequential"));
info->read_record_func= rr_sequential;
if (table->file->ha_rnd_init_with_error(1))
DBUG_RETURN(1);
/* We can use record cache if we don't update dynamic length tables */
if (!table->no_cache &&
(use_record_cache > 0 ||
(int) table->reginfo.lock_type <= (int) TL_READ_HIGH_PRIORITY ||
!(table->s->db_options_in_use & HA_OPTION_PACK_RECORD) ||
(use_record_cache < 0 &&
!(table->file->ha_table_flags() & HA_NOT_DELETE_WITH_CACHE))))
(void) table->file->extra_opt(HA_EXTRA_CACHE,
thd->variables.read_buff_size);
}
/* Condition pushdown to storage engine */
if ((table->file->ha_table_flags() & HA_CAN_TABLE_CONDITION_PUSHDOWN) &&
select && select->cond &&
(select->cond->used_tables() & table->map) &&
!table->file->pushed_cond)
table->file->cond_push(select->cond);
DBUG_RETURN(0);
} /* init_read_record */
void end_read_record(READ_RECORD *info)
{ /* free cache if used */
if (info->cache)
{
my_free_lock(info->cache);
info->cache=0;
}
if (info->table)
{
if (info->table->is_created())
(void) info->table->file->extra(HA_EXTRA_NO_CACHE);
if (info->read_record_func != rr_quick) // otherwise quick_range does it
(void) info->table->file->ha_index_or_rnd_end();
info->table=0;
}
}
static int rr_handle_error(READ_RECORD *info, int error)
{
if (info->thd->killed)
{
info->thd->send_kill_message();
return 1;
}
if (error == HA_ERR_END_OF_FILE)
error= -1;
else
{
if (info->print_error)
info->table->file->print_error(error, MYF(0));
if (error < 0) // Fix negative BDB errno
error= 1;
}
return error;
}
/** Read a record from head-database. */
static int rr_quick(READ_RECORD *info)
{
int tmp;
while ((tmp= info->select->quick->get_next()))
{
if (info->thd->killed || (tmp != HA_ERR_RECORD_DELETED))
{
tmp= rr_handle_error(info, tmp);
break;
}
}
return tmp;
}
/**
Reads first row in an index scan.
@param info Scan info
@retval
0 Ok
@retval
-1 End of records
@retval
1 Error
*/
static int rr_index_first(READ_RECORD *info)
{
int tmp;
// tell handler that we are doing an index scan
if ((tmp = info->table->file->prepare_index_scan()))
{
tmp= rr_handle_error(info, tmp);
return tmp;
}
tmp= info->table->file->ha_index_first(info->record);
info->read_record_func= rr_index;
if (tmp)
tmp= rr_handle_error(info, tmp);
return tmp;
}
/**
Reads last row in an index scan.
@param info Scan info
@retval
0 Ok
@retval
-1 End of records
@retval
1 Error
*/
static int rr_index_last(READ_RECORD *info)
{
int tmp= info->table->file->ha_index_last(info->record);
info->read_record_func= rr_index_desc;
if (tmp)
tmp= rr_handle_error(info, tmp);
return tmp;
}
/**
Reads index sequentially after first row.
Read the next index record (in forward direction) and translate return
value.
@param info Scan info
@retval
0 Ok
@retval
-1 End of records
@retval
1 Error
*/
static int rr_index(READ_RECORD *info)
{
int tmp= info->table->file->ha_index_next(info->record);
if (tmp)
tmp= rr_handle_error(info, tmp);
return tmp;
}
/**
Reads index sequentially from the last row to the first.
Read the prev index record (in backward direction) and translate return
value.
@param info Scan info
@retval
0 Ok
@retval
-1 End of records
@retval
1 Error
*/
static int rr_index_desc(READ_RECORD *info)
{
int tmp= info->table->file->ha_index_prev(info->record);
if (tmp)
tmp= rr_handle_error(info, tmp);
return tmp;
}
int rr_sequential(READ_RECORD *info)
{
int tmp;
while ((tmp= info->table->file->ha_rnd_next(info->record)))
{
/*
rnd_next can return RECORD_DELETED for MyISAM when one thread is
reading and another deleting without locks.
*/
if (info->thd->killed || (tmp != HA_ERR_RECORD_DELETED))
{
tmp= rr_handle_error(info, tmp);
break;
}
}
return tmp;
}
static int rr_from_tempfile(READ_RECORD *info)
{
int tmp;
for (;;)
{
if (my_b_read(info->io_cache,info->ref_pos,info->ref_length))
return -1; /* End of file */
if (!(tmp= info->table->file->ha_rnd_pos(info->record,info->ref_pos)))
break;
/* The following is extremely unlikely to happen */
if (tmp == HA_ERR_RECORD_DELETED ||
(tmp == HA_ERR_KEY_NOT_FOUND && info->ignore_not_found_rows))
continue;
tmp= rr_handle_error(info, tmp);
break;
}
return tmp;
} /* rr_from_tempfile */
/**
Read a result set record from a temporary file after sorting.
The function first reads the next sorted record from the temporary file.
into a buffer. If a success it calls a callback function that unpacks
the fields values use in the result set from this buffer into their
positions in the regular record buffer.
@param info Reference to the context including record descriptors
@retval
0 Record successfully read.
@retval
-1 There is no record to be read anymore.
*/
static int rr_unpack_from_tempfile(READ_RECORD *info)
{
if (my_b_read(info->io_cache, info->rec_buf, info->ref_length))
return -1;
(*info->unpack)(info->addon_field, info->rec_buf,
info->rec_buf + info->ref_length);
return 0;
}
int rr_from_pointers(READ_RECORD *info)
{
int tmp;
uchar *cache_pos;
for (;;)
{
if (info->cache_pos == info->cache_end)
return -1; /* End of file */
cache_pos= info->cache_pos;
info->cache_pos+= info->ref_length;
if (!(tmp= info->table->file->ha_rnd_pos(info->record,cache_pos)))
break;
/* The following is extremely unlikely to happen */
if (tmp == HA_ERR_RECORD_DELETED ||
(tmp == HA_ERR_KEY_NOT_FOUND && info->ignore_not_found_rows))
continue;
tmp= rr_handle_error(info, tmp);
break;
}
return tmp;
}
/**
Read a result set record from a buffer after sorting.
The function first reads the next sorted record from the sort buffer.
If a success it calls a callback function that unpacks
the fields values use in the result set from this buffer into their
positions in the regular record buffer.
@param info Reference to the context including record descriptors
@retval
0 Record successfully read.
@retval
-1 There is no record to be read anymore.
*/
static int rr_unpack_from_buffer(READ_RECORD *info)
{
if (info->cache_pos == info->cache_end)
return -1; /* End of buffer */
(*info->unpack)(info->addon_field, info->cache_pos,
info->cache_end);
info->cache_pos+= info->ref_length;
return 0;
}
/* cacheing of records from a database */
static int init_rr_cache(THD *thd, READ_RECORD *info)
{
uint rec_cache_size;
DBUG_ENTER("init_rr_cache");
info->struct_length= 3+MAX_REFLENGTH;
info->reclength= ALIGN_SIZE(info->table->s->reclength+1);
if (info->reclength < info->struct_length)
info->reclength= ALIGN_SIZE(info->struct_length);
info->error_offset= info->table->s->reclength;
info->cache_records= (thd->variables.read_rnd_buff_size /
(info->reclength+info->struct_length));
rec_cache_size= info->cache_records*info->reclength;
info->rec_cache_size= info->cache_records*info->ref_length;
// We have to allocate one more byte to use uint3korr (see comments for it)
if (info->cache_records <= 2 ||
!(info->cache=(uchar*) my_malloc_lock(rec_cache_size+info->cache_records*
info->struct_length+1,
MYF(MY_THREAD_SPECIFIC))))
DBUG_RETURN(1);
#ifdef HAVE_valgrind
// Avoid warnings in qsort
bzero(info->cache,rec_cache_size+info->cache_records* info->struct_length+1);
#endif
DBUG_PRINT("info",("Allocated buffert for %d records",info->cache_records));
info->read_positions=info->cache+rec_cache_size;
info->cache_pos=info->cache_end=info->cache;
DBUG_RETURN(0);
} /* init_rr_cache */
static int rr_from_cache(READ_RECORD *info)
{
reg1 uint i;
ulong length;
my_off_t rest_of_file;
int16 error;
uchar *position,*ref_position,*record_pos;
ulong record;
for (;;)
{
if (info->cache_pos != info->cache_end)
{
if (info->cache_pos[info->error_offset])
{
shortget(error,info->cache_pos);
if (info->print_error)
info->table->file->print_error(error,MYF(0));
}
else
{
error=0;
memcpy(info->record,info->cache_pos,
(size_t) info->table->s->reclength);
}
info->cache_pos+=info->reclength;
return ((int) error);
}
length=info->rec_cache_size;
rest_of_file=info->io_cache->end_of_file - my_b_tell(info->io_cache);
if ((my_off_t) length > rest_of_file)
length= (ulong) rest_of_file;
if (!length || my_b_read(info->io_cache,info->cache,length))
{
DBUG_PRINT("info",("Found end of file"));
return -1; /* End of file */
}
length/=info->ref_length;
position=info->cache;
ref_position=info->read_positions;
for (i=0 ; i < length ; i++,position+=info->ref_length)
{
memcpy(ref_position,position,(size_t) info->ref_length);
ref_position+=MAX_REFLENGTH;
int3store(ref_position,(long) i);
ref_position+=3;
}
my_qsort(info->read_positions, length, info->struct_length,
(qsort_cmp) rr_cmp);
position=info->read_positions;
for (i=0 ; i < length ; i++)
{
memcpy(info->ref_pos,position,(size_t) info->ref_length);
position+=MAX_REFLENGTH;
record=uint3korr(position);
position+=3;
record_pos=info->cache+record*info->reclength;
if ((error=(int16) info->table->file->ha_rnd_pos(record_pos,info->ref_pos)))
{
record_pos[info->error_offset]=1;
shortstore(record_pos,error);
DBUG_PRINT("error",("Got error: %d:%d when reading row",
my_errno, error));
}
else
record_pos[info->error_offset]=0;
}
info->cache_end=(info->cache_pos=info->cache)+length*info->reclength;
}
} /* rr_from_cache */
static int rr_cmp(uchar *a,uchar *b)
{
if (a[0] != b[0])
return (int) a[0] - (int) b[0];
if (a[1] != b[1])
return (int) a[1] - (int) b[1];
if (a[2] != b[2])
return (int) a[2] - (int) b[2];
#if MAX_REFLENGTH == 4
return (int) a[3] - (int) b[3];
#else
if (a[3] != b[3])
return (int) a[3] - (int) b[3];
if (a[4] != b[4])
return (int) a[4] - (int) b[4];
if (a[5] != b[5])
return (int) a[5] - (int) b[5];
if (a[6] != b[6])
return (int) a[6] - (int) b[6];
return (int) a[7] - (int) b[7];
#endif
}
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