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mariadb/storage/heap/ha_heap.cc
Davi Arnaut a10ae35328 Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled 
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
2010-07-08 18:20:08 -03:00

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/* Copyright (C) 2000-2006 MySQL AB, 2008-2009 Sun Microsystems, Inc
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#define MYSQL_SERVER 1
#include "sql_priv.h"
#include "probes_mysql.h"
#include "sql_plugin.h"
#include "ha_heap.h"
#include "heapdef.h"
#include "sql_base.h" // enum_tdc_remove_table_type
static handler *heap_create_handler(handlerton *hton,
TABLE_SHARE *table,
MEM_ROOT *mem_root);
static int
heap_prepare_hp_create_info(TABLE *table_arg, bool internal_table,
HP_CREATE_INFO *hp_create_info);
int heap_panic(handlerton *hton, ha_panic_function flag)
{
return hp_panic(flag);
}
int heap_init(void *p)
{
handlerton *heap_hton;
#ifdef HAVE_PSI_INTERFACE
init_heap_psi_keys();
#endif
heap_hton= (handlerton *)p;
heap_hton->state= SHOW_OPTION_YES;
heap_hton->db_type= DB_TYPE_HEAP;
heap_hton->create= heap_create_handler;
heap_hton->panic= heap_panic;
heap_hton->flags= HTON_CAN_RECREATE;
return 0;
}
static handler *heap_create_handler(handlerton *hton,
TABLE_SHARE *table,
MEM_ROOT *mem_root)
{
return new (mem_root) ha_heap(hton, table);
}
/*****************************************************************************
** HEAP tables
*****************************************************************************/
ha_heap::ha_heap(handlerton *hton, TABLE_SHARE *table_arg)
:handler(hton, table_arg), file(0), records_changed(0), key_stat_version(0),
internal_table(0)
{}
static const char *ha_heap_exts[] = {
NullS
};
const char **ha_heap::bas_ext() const
{
return ha_heap_exts;
}
/*
Hash index statistics is updated (copied from HP_KEYDEF::hash_buckets to
rec_per_key) after 1/HEAP_STATS_UPDATE_THRESHOLD fraction of table records
have been inserted/updated/deleted. delete_all_rows() and table flush cause
immediate update.
NOTE
hash index statistics must be updated when number of table records changes
from 0 to non-zero value and vice versa. Otherwise records_in_range may
erroneously return 0 and 'range' may miss records.
*/
#define HEAP_STATS_UPDATE_THRESHOLD 10
int ha_heap::open(const char *name, int mode, uint test_if_locked)
{
internal_table= test(test_if_locked & HA_OPEN_INTERNAL_TABLE);
if (internal_table || (!(file= heap_open(name, mode)) && my_errno == ENOENT))
{
HP_CREATE_INFO create_info;
my_bool created_new_share;
int rc;
file= 0;
if (heap_prepare_hp_create_info(table, internal_table, &create_info))
goto end;
create_info.pin_share= TRUE;
rc= heap_create(name, &create_info, &internal_share, &created_new_share);
my_free(create_info.keydef);
if (rc)
goto end;
implicit_emptied= test(created_new_share);
if (internal_table)
file= heap_open_from_share(internal_share, mode);
else
file= heap_open_from_share_and_register(internal_share, mode);
if (!file)
{
heap_release_share(internal_share, internal_table);
goto end;
}
}
ref_length= sizeof(HEAP_PTR);
/* Initialize variables for the opened table */
set_keys_for_scanning();
/*
We cannot run update_key_stats() here because we do not have a
lock on the table. The 'records' count might just be changed
temporarily at this moment and we might get wrong statistics (Bug
#10178). Instead we request for update. This will be done in
ha_heap::info(), which is always called before key statistics are
used.
*/
key_stat_version= file->s->key_stat_version-1;
end:
return (file ? 0 : 1);
}
int ha_heap::close(void)
{
return internal_table ? hp_close(file) : heap_close(file);
}
/*
Create a copy of this table
DESCRIPTION
Do same as default implementation but use file->s->name instead of
table->s->path. This is needed by Windows where the clone() call sees
'/'-delimited path in table->s->path, while ha_peap::open() was called
with '\'-delimited path.
*/
handler *ha_heap::clone(MEM_ROOT *mem_root)
{
handler *new_handler= get_new_handler(table->s, mem_root, table->s->db_type());
if (new_handler && !new_handler->ha_open(table, file->s->name, table->db_stat,
HA_OPEN_IGNORE_IF_LOCKED))
return new_handler;
return NULL; /* purecov: inspected */
}
/*
Compute which keys to use for scanning
SYNOPSIS
set_keys_for_scanning()
no parameter
DESCRIPTION
Set the bitmap btree_keys, which is used when the upper layers ask
which keys to use for scanning. For each btree index the
corresponding bit is set.
RETURN
void
*/
void ha_heap::set_keys_for_scanning(void)
{
btree_keys.clear_all();
for (uint i= 0 ; i < table->s->keys ; i++)
{
if (table->key_info[i].algorithm == HA_KEY_ALG_BTREE)
btree_keys.set_bit(i);
}
}
void ha_heap::update_key_stats()
{
for (uint i= 0; i < table->s->keys; i++)
{
KEY *key=table->key_info+i;
if (!key->rec_per_key)
continue;
if (key->algorithm != HA_KEY_ALG_BTREE)
{
if (key->flags & HA_NOSAME)
key->rec_per_key[key->key_parts-1]= 1;
else
{
ha_rows hash_buckets= file->s->keydef[i].hash_buckets;
uint no_records= hash_buckets ? (uint) (file->s->records/hash_buckets) : 2;
if (no_records < 2)
no_records= 2;
key->rec_per_key[key->key_parts-1]= no_records;
}
}
}
records_changed= 0;
/* At the end of update_key_stats() we can proudly claim they are OK. */
key_stat_version= file->s->key_stat_version;
}
int ha_heap::write_row(uchar * buf)
{
int res;
ha_statistic_increment(&SSV::ha_write_count);
if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_INSERT)
table->timestamp_field->set_time();
if (table->next_number_field && buf == table->record[0])
{
if ((res= update_auto_increment()))
return res;
}
res= heap_write(file,buf);
if (!res && (++records_changed*HEAP_STATS_UPDATE_THRESHOLD >
file->s->records))
{
/*
We can perform this safely since only one writer at the time is
allowed on the table.
*/
file->s->key_stat_version++;
}
return res;
}
int ha_heap::update_row(const uchar * old_data, uchar * new_data)
{
int res;
ha_statistic_increment(&SSV::ha_update_count);
if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_UPDATE)
table->timestamp_field->set_time();
res= heap_update(file,old_data,new_data);
if (!res && ++records_changed*HEAP_STATS_UPDATE_THRESHOLD >
file->s->records)
{
/*
We can perform this safely since only one writer at the time is
allowed on the table.
*/
file->s->key_stat_version++;
}
return res;
}
int ha_heap::delete_row(const uchar * buf)
{
int res;
ha_statistic_increment(&SSV::ha_delete_count);
res= heap_delete(file,buf);
if (!res && table->s->tmp_table == NO_TMP_TABLE &&
++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
{
/*
We can perform this safely since only one writer at the time is
allowed on the table.
*/
file->s->key_stat_version++;
}
return res;
}
int ha_heap::index_read_map(uchar *buf, const uchar *key,
key_part_map keypart_map,
enum ha_rkey_function find_flag)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_key_count);
int error = heap_rkey(file,buf,active_index, key, keypart_map, find_flag);
table->status = error ? STATUS_NOT_FOUND : 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_read_last_map(uchar *buf, const uchar *key,
key_part_map keypart_map)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_key_count);
int error= heap_rkey(file, buf, active_index, key, keypart_map,
HA_READ_PREFIX_LAST);
table->status= error ? STATUS_NOT_FOUND : 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_read_idx_map(uchar *buf, uint index, const uchar *key,
key_part_map keypart_map,
enum ha_rkey_function find_flag)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
ha_statistic_increment(&SSV::ha_read_key_count);
int error = heap_rkey(file, buf, index, key, keypart_map, find_flag);
table->status = error ? STATUS_NOT_FOUND : 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_next(uchar * buf)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_next_count);
int error=heap_rnext(file,buf);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_prev(uchar * buf)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_prev_count);
int error=heap_rprev(file,buf);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_first(uchar * buf)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_first_count);
int error=heap_rfirst(file, buf, active_index);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::index_last(uchar * buf)
{
MYSQL_INDEX_READ_ROW_START(table_share->db.str, table_share->table_name.str);
DBUG_ASSERT(inited==INDEX);
ha_statistic_increment(&SSV::ha_read_last_count);
int error=heap_rlast(file, buf, active_index);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_INDEX_READ_ROW_DONE(error);
return error;
}
int ha_heap::rnd_init(bool scan)
{
return scan ? heap_scan_init(file) : 0;
}
int ha_heap::rnd_next(uchar *buf)
{
MYSQL_READ_ROW_START(table_share->db.str, table_share->table_name.str,
TRUE);
ha_statistic_increment(&SSV::ha_read_rnd_next_count);
int error=heap_scan(file, buf);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_READ_ROW_DONE(error);
return error;
}
int ha_heap::rnd_pos(uchar * buf, uchar *pos)
{
int error;
HEAP_PTR heap_position;
MYSQL_READ_ROW_START(table_share->db.str, table_share->table_name.str,
FALSE);
ha_statistic_increment(&SSV::ha_read_rnd_count);
memcpy_fixed((char*) &heap_position, pos, sizeof(HEAP_PTR));
error=heap_rrnd(file, buf, heap_position);
table->status=error ? STATUS_NOT_FOUND: 0;
MYSQL_READ_ROW_DONE(error);
return error;
}
void ha_heap::position(const uchar *record)
{
*(HEAP_PTR*) ref= heap_position(file); // Ref is aligned
}
int ha_heap::info(uint flag)
{
HEAPINFO hp_info;
(void) heap_info(file,&hp_info,flag);
errkey= hp_info.errkey;
stats.records= hp_info.records;
stats.deleted= hp_info.deleted;
stats.mean_rec_length= hp_info.reclength;
stats.data_file_length= hp_info.data_length;
stats.index_file_length= hp_info.index_length;
stats.max_data_file_length= hp_info.max_records * hp_info.reclength;
stats.delete_length= hp_info.deleted * hp_info.reclength;
if (flag & HA_STATUS_AUTO)
stats.auto_increment_value= hp_info.auto_increment;
/*
If info() is called for the first time after open(), we will still
have to update the key statistics. Hoping that a table lock is now
in place.
*/
if (key_stat_version != file->s->key_stat_version)
update_key_stats();
return 0;
}
int ha_heap::extra(enum ha_extra_function operation)
{
return heap_extra(file,operation);
}
int ha_heap::reset()
{
return heap_reset(file);
}
int ha_heap::delete_all_rows()
{
heap_clear(file);
if (table->s->tmp_table == NO_TMP_TABLE)
{
/*
We can perform this safely since only one writer at the time is
allowed on the table.
*/
file->s->key_stat_version++;
}
return 0;
}
int ha_heap::reset_auto_increment(ulonglong value)
{
file->s->auto_increment= value;
return 0;
}
int ha_heap::external_lock(THD *thd, int lock_type)
{
return 0; // No external locking
}
/*
Disable indexes.
SYNOPSIS
disable_indexes()
mode mode of operation:
HA_KEY_SWITCH_NONUNIQ disable all non-unique keys
HA_KEY_SWITCH_ALL disable all keys
HA_KEY_SWITCH_NONUNIQ_SAVE dis. non-uni. and make persistent
HA_KEY_SWITCH_ALL_SAVE dis. all keys and make persistent
DESCRIPTION
Disable indexes and clear keys to use for scanning.
IMPLEMENTATION
HA_KEY_SWITCH_NONUNIQ is not implemented.
HA_KEY_SWITCH_NONUNIQ_SAVE is not implemented with HEAP.
HA_KEY_SWITCH_ALL_SAVE is not implemented with HEAP.
RETURN
0 ok
HA_ERR_WRONG_COMMAND mode not implemented.
*/
int ha_heap::disable_indexes(uint mode)
{
int error;
if (mode == HA_KEY_SWITCH_ALL)
{
if (!(error= heap_disable_indexes(file)))
set_keys_for_scanning();
}
else
{
/* mode not implemented */
error= HA_ERR_WRONG_COMMAND;
}
return error;
}
/*
Enable indexes.
SYNOPSIS
enable_indexes()
mode mode of operation:
HA_KEY_SWITCH_NONUNIQ enable all non-unique keys
HA_KEY_SWITCH_ALL enable all keys
HA_KEY_SWITCH_NONUNIQ_SAVE en. non-uni. and make persistent
HA_KEY_SWITCH_ALL_SAVE en. all keys and make persistent
DESCRIPTION
Enable indexes and set keys to use for scanning.
The indexes might have been disabled by disable_index() before.
The function works only if both data and indexes are empty,
since the heap storage engine cannot repair the indexes.
To be sure, call handler::delete_all_rows() before.
IMPLEMENTATION
HA_KEY_SWITCH_NONUNIQ is not implemented.
HA_KEY_SWITCH_NONUNIQ_SAVE is not implemented with HEAP.
HA_KEY_SWITCH_ALL_SAVE is not implemented with HEAP.
RETURN
0 ok
HA_ERR_CRASHED data or index is non-empty. Delete all rows and retry.
HA_ERR_WRONG_COMMAND mode not implemented.
*/
int ha_heap::enable_indexes(uint mode)
{
int error;
if (mode == HA_KEY_SWITCH_ALL)
{
if (!(error= heap_enable_indexes(file)))
set_keys_for_scanning();
}
else
{
/* mode not implemented */
error= HA_ERR_WRONG_COMMAND;
}
return error;
}
/*
Test if indexes are disabled.
SYNOPSIS
indexes_are_disabled()
no parameters
RETURN
0 indexes are not disabled
1 all indexes are disabled
[2 non-unique indexes are disabled - NOT YET IMPLEMENTED]
*/
int ha_heap::indexes_are_disabled(void)
{
return heap_indexes_are_disabled(file);
}
THR_LOCK_DATA **ha_heap::store_lock(THD *thd,
THR_LOCK_DATA **to,
enum thr_lock_type lock_type)
{
if (lock_type != TL_IGNORE && file->lock.type == TL_UNLOCK)
file->lock.type=lock_type;
*to++= &file->lock;
return to;
}
/*
We have to ignore ENOENT entries as the HEAP table is created on open and
not when doing a CREATE on the table.
*/
int ha_heap::delete_table(const char *name)
{
int error= heap_delete_table(name);
return error == ENOENT ? 0 : error;
}
void ha_heap::drop_table(const char *name)
{
file->s->delete_on_close= 1;
close();
}
int ha_heap::rename_table(const char * from, const char * to)
{
return heap_rename(from,to);
}
ha_rows ha_heap::records_in_range(uint inx, key_range *min_key,
key_range *max_key)
{
KEY *key=table->key_info+inx;
if (key->algorithm == HA_KEY_ALG_BTREE)
return hp_rb_records_in_range(file, inx, min_key, max_key);
if (!min_key || !max_key ||
min_key->length != max_key->length ||
min_key->length != key->key_length ||
min_key->flag != HA_READ_KEY_EXACT ||
max_key->flag != HA_READ_AFTER_KEY)
return HA_POS_ERROR; // Can only use exact keys
if (stats.records <= 1)
return stats.records;
/* Assert that info() did run. We need current statistics here. */
DBUG_ASSERT(key_stat_version == file->s->key_stat_version);
return key->rec_per_key[key->key_parts-1];
}
static int
heap_prepare_hp_create_info(TABLE *table_arg, bool internal_table,
HP_CREATE_INFO *hp_create_info)
{
uint key, parts, mem_per_row= 0, keys= table_arg->s->keys;
uint auto_key= 0, auto_key_type= 0;
ha_rows max_rows;
HP_KEYDEF *keydef;
HA_KEYSEG *seg;
TABLE_SHARE *share= table_arg->s;
bool found_real_auto_increment= 0;
bzero(hp_create_info, sizeof(*hp_create_info));
for (key= parts= 0; key < keys; key++)
parts+= table_arg->key_info[key].key_parts;
if (!(keydef= (HP_KEYDEF*) my_malloc(keys * sizeof(HP_KEYDEF) +
parts * sizeof(HA_KEYSEG),
MYF(MY_WME))))
return my_errno;
seg= my_reinterpret_cast(HA_KEYSEG*) (keydef + keys);
for (key= 0; key < keys; key++)
{
KEY *pos= table_arg->key_info+key;
KEY_PART_INFO *key_part= pos->key_part;
KEY_PART_INFO *key_part_end= key_part + pos->key_parts;
keydef[key].keysegs= (uint) pos->key_parts;
keydef[key].flag= (pos->flags & (HA_NOSAME | HA_NULL_ARE_EQUAL));
keydef[key].seg= seg;
switch (pos->algorithm) {
case HA_KEY_ALG_UNDEF:
case HA_KEY_ALG_HASH:
keydef[key].algorithm= HA_KEY_ALG_HASH;
mem_per_row+= sizeof(char*) * 2; // = sizeof(HASH_INFO)
break;
case HA_KEY_ALG_BTREE:
keydef[key].algorithm= HA_KEY_ALG_BTREE;
mem_per_row+=sizeof(TREE_ELEMENT)+pos->key_length+sizeof(char*);
break;
default:
DBUG_ASSERT(0); // cannot happen
}
for (; key_part != key_part_end; key_part++, seg++)
{
Field *field= key_part->field;
if (pos->algorithm == HA_KEY_ALG_BTREE)
seg->type= field->key_type();
else
{
if ((seg->type = field->key_type()) != (int) HA_KEYTYPE_TEXT &&
seg->type != HA_KEYTYPE_VARTEXT1 &&
seg->type != HA_KEYTYPE_VARTEXT2 &&
seg->type != HA_KEYTYPE_VARBINARY1 &&
seg->type != HA_KEYTYPE_VARBINARY2)
seg->type= HA_KEYTYPE_BINARY;
}
seg->start= (uint) key_part->offset;
seg->length= (uint) key_part->length;
seg->flag= key_part->key_part_flag;
if (field->flags & (ENUM_FLAG | SET_FLAG))
seg->charset= &my_charset_bin;
else
seg->charset= field->charset_for_protocol();
if (field->null_ptr)
{
seg->null_bit= field->null_bit;
seg->null_pos= (uint) (field->null_ptr - (uchar*) table_arg->record[0]);
}
else
{
seg->null_bit= 0;
seg->null_pos= 0;
}
if (field->flags & AUTO_INCREMENT_FLAG &&
table_arg->found_next_number_field &&
key == share->next_number_index)
{
/*
Store key number and type for found auto_increment key
We have to store type as seg->type can differ from it
*/
auto_key= key+ 1;
auto_key_type= field->key_type();
}
}
}
mem_per_row+= MY_ALIGN(share->reclength + 1, sizeof(char*));
if (table_arg->found_next_number_field)
{
keydef[share->next_number_index].flag|= HA_AUTO_KEY;
found_real_auto_increment= share->next_number_key_offset == 0;
}
hp_create_info->auto_key= auto_key;
hp_create_info->auto_key_type= auto_key_type;
hp_create_info->max_table_size=current_thd->variables.max_heap_table_size;
hp_create_info->with_auto_increment= found_real_auto_increment;
hp_create_info->internal_table= internal_table;
max_rows= (ha_rows) (hp_create_info->max_table_size / mem_per_row);
if (share->max_rows && share->max_rows < max_rows)
max_rows= share->max_rows;
hp_create_info->max_records= (ulong) max_rows;
hp_create_info->min_records= (ulong) share->min_rows;
hp_create_info->keys= share->keys;
hp_create_info->reclength= share->reclength;
hp_create_info->keydef= keydef;
return 0;
}
int ha_heap::create(const char *name, TABLE *table_arg,
HA_CREATE_INFO *create_info)
{
int error;
my_bool created;
HP_CREATE_INFO hp_create_info;
error= heap_prepare_hp_create_info(table_arg, internal_table,
&hp_create_info);
if (error)
return error;
hp_create_info.auto_increment= (create_info->auto_increment_value ?
create_info->auto_increment_value - 1 : 0);
error= heap_create(name, &hp_create_info, &internal_share, &created);
my_free(hp_create_info.keydef);
DBUG_ASSERT(file == 0);
return (error);
}
void ha_heap::update_create_info(HA_CREATE_INFO *create_info)
{
table->file->info(HA_STATUS_AUTO);
if (!(create_info->used_fields & HA_CREATE_USED_AUTO))
create_info->auto_increment_value= stats.auto_increment_value;
}
void ha_heap::get_auto_increment(ulonglong offset, ulonglong increment,
ulonglong nb_desired_values,
ulonglong *first_value,
ulonglong *nb_reserved_values)
{
ha_heap::info(HA_STATUS_AUTO);
*first_value= stats.auto_increment_value;
/* such table has only table-level locking so reserves up to +inf */
*nb_reserved_values= ULONGLONG_MAX;
}
bool ha_heap::check_if_incompatible_data(HA_CREATE_INFO *info,
uint table_changes)
{
/* Check that auto_increment value was not changed */
if ((info->used_fields & HA_CREATE_USED_AUTO &&
info->auto_increment_value != 0) ||
table_changes == IS_EQUAL_NO ||
table_changes & IS_EQUAL_PACK_LENGTH) // Not implemented yet
return COMPATIBLE_DATA_NO;
return COMPATIBLE_DATA_YES;
}
struct st_mysql_storage_engine heap_storage_engine=
{ MYSQL_HANDLERTON_INTERFACE_VERSION };
mysql_declare_plugin(heap)
{
MYSQL_STORAGE_ENGINE_PLUGIN,
&heap_storage_engine,
"MEMORY",
"MySQL AB",
"Hash based, stored in memory, useful for temporary tables",
PLUGIN_LICENSE_GPL,
heap_init,
NULL,
0x0100, /* 1.0 */
NULL, /* status variables */
NULL, /* system variables */
NULL /* config options */
}
mysql_declare_plugin_end;
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