mariadb/sql/table_cache.h
Sergey Vojtovich b95c8ce530 MDEV-5675 - Performance: my_hash_sort_bin is called too often
Reduced number of my_hash_sort_bin() calls from 4 to 1 per query.
Reduced number of memory accesses done by my_hash_sort_bin().

Details:
- let MDL subsystem use pre-calculated hash value for hash
  inserts and deletes
- let table cache use pre-calculated MDL hash value
- MDL namespace is excluded from hash value calculation, so that
  hash value can be used by table cache as is
- hash value for MDL is calculated as resulting hash value + MDL
  namespace
- extended hash implementation to accept user defined hash function
2014-03-06 16:19:12 +04:00

138 lines
4.9 KiB
C++

/* Copyright (c) 2000, 2012, Oracle and/or its affiliates.
Copyright (c) 2010, 2011 Monty Program Ab
Copyright (C) 2013 Sergey Vojtovich and MariaDB Foundation
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 */
enum enum_tdc_remove_table_type
{
TDC_RT_REMOVE_ALL,
TDC_RT_REMOVE_NOT_OWN,
TDC_RT_REMOVE_UNUSED,
TDC_RT_REMOVE_NOT_OWN_KEEP_SHARE
};
extern ulong tdc_size;
extern ulong tc_size;
extern mysql_mutex_t LOCK_open; /* FIXME: make private */
extern int tdc_init(void);
extern void tdc_start_shutdown(void);
extern void tdc_deinit(void);
extern ulong tdc_records(void);
extern void tdc_purge(bool all);
extern void tdc_init_share(TABLE_SHARE *share);
extern void tdc_deinit_share(TABLE_SHARE *share);
extern TABLE_SHARE *tdc_lock_share(const char *db, const char *table_name);
extern void tdc_unlock_share(TABLE_SHARE *share);
extern TABLE_SHARE *tdc_acquire_share(THD *thd, const char *db,
const char *table_name,
const char *key, uint key_length,
my_hash_value_type hash_value,
uint flags, TABLE **out_table);
extern void tdc_release_share(TABLE_SHARE *share);
extern bool tdc_remove_table(THD *thd, enum_tdc_remove_table_type remove_type,
const char *db, const char *table_name,
bool kill_delayed_threads);
extern int tdc_wait_for_old_version(THD *thd, const char *db,
const char *table_name,
ulong wait_timeout, uint deadlock_weight,
ulong refresh_version= ULONG_MAX);
extern ulong tdc_refresh_version(void);
extern ulong tdc_increment_refresh_version(void);
extern void tdc_assign_new_table_id(TABLE_SHARE *share);
extern uint tc_records(void);
extern void tc_purge(bool mark_flushed= false);
extern void tc_add_table(THD *thd, TABLE *table);
extern bool tc_release_table(TABLE *table);
/**
Create a table cache key for non-temporary table.
@param key Buffer for key (must be at least NAME_LEN*2+2 bytes).
@param db Database name.
@param table_name Table name.
@return Length of key.
*/
inline uint tdc_create_key(char *key, const char *db, const char *table_name)
{
/*
In theory caller should ensure that both db and table_name are
not longer than NAME_LEN bytes. In practice we play safe to avoid
buffer overruns.
*/
return (uint) (strmake(strmake(key, db, NAME_LEN) + 1, table_name,
NAME_LEN) - key + 1);
}
/**
Convenience helper: call tdc_acquire_share() without out_table.
*/
static inline TABLE_SHARE *tdc_acquire_share(THD *thd, const char *db,
const char *table_name,
const char *key,
uint key_length, uint flags)
{
return tdc_acquire_share(thd, db, table_name, key, key_length,
my_hash_sort(&my_charset_bin, (uchar*) key,
key_length), flags, 0);
}
/**
Convenience helper: call tdc_acquire_share() without precomputed cache key.
*/
static inline TABLE_SHARE *tdc_acquire_share(THD *thd, const char *db,
const char *table_name, uint flags)
{
char key[MAX_DBKEY_LENGTH];
uint key_length;
key_length= tdc_create_key(key, db, table_name);
return tdc_acquire_share(thd, db, table_name, key, key_length, flags);
}
/**
Convenience helper: call tdc_acquire_share() reusing the MDL cache key.
@note lifetime of the returned TABLE_SHARE is limited by the
lifetime of the TABLE_LIST object!!!
*/
uint get_table_def_key(const TABLE_LIST *table_list, const char **key);
static inline TABLE_SHARE *tdc_acquire_share_shortlived(THD *thd, TABLE_LIST *tl,
uint flags)
{
const char *key;
uint key_length= get_table_def_key(tl, &key);
return tdc_acquire_share(thd, tl->db, tl->table_name, key, key_length,
tl->mdl_request.key.tc_hash_value(), flags, 0);
}
class TDC_iterator
{
ulong idx;
public:
void init(void);
void deinit(void);
TABLE_SHARE *next(void);
};