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mariadb/include/heap.h
Monty 52c29f3bdc MDEV-35469 Heap tables are calling mallocs to often 
Heap tables are allocated blocks to store rows according to
my_default_record_cache (mapped to the server global variable
 read_buffer_size).
This causes performance issues when the record length is big
(> 1000 bytes) and the my_default_record_cache is small.

Changed to instead split the default heap allocation to 1/16 of the
allowed space and not use my_default_record_cache anymore when creating
the heap. The allocation is also aligned to be just under a power of 2.

For some test that I have been running, which was using record length=633,
the speed of the query doubled thanks to this change.

Other things:
- Fixed calculation of max_records passed to hp_create() to take
  into account padding between records.
- Updated calculation of memory needed by heap tables. Before we
  did not take into account internal structures needed to access rows.
- Changed block sized for memory_table from 1 to 16384 to get less
  fragmentation. This also avoids a problem where we need 1K
  to manage index and row storage which was not counted for before.
- Moved heap memory usage to a separate test for 32 bit.
- Allocate all data blocks in heap in powers of 2. Change reported
  memory usage for heap to reflect this.

Reviewed-by: Sergei Golubchik <serg@mariadb.org>
2025-01-05 16:40:11 +02:00

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/* Copyright (c) 2000, 2011, Oracle and/or its affiliates.
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
*/
/* This file should be included when using heap_database_functions */
/* Author: Michael Widenius */
#ifndef _heap_h
#define _heap_h
#ifdef __cplusplus
extern "C" {
#endif
#ifndef _my_base_h
#include <my_base.h>
#endif
#include <my_pthread.h>
#include <thr_lock.h>
#include "my_compare.h"
#include "my_tree.h"
/* defines used by heap-functions */
#define HP_MAX_LEVELS 4 /* 128^5 records is enough */
#define HP_PTRS_IN_NOD 128
/* struct used with heap_functions */
typedef struct st_heapinfo /* Struct from heap_info */
{
ulong records; /* Records in database */
ulong deleted; /* Deleted records in database */
ulong max_records;
ulonglong data_length;
ulonglong index_length;
uint reclength; /* Length of one record */
int errkey;
ulonglong auto_increment;
time_t create_time;
} HEAPINFO;
/* Structs used by heap-database-handler */
typedef struct st_heap_ptrs
{
uchar *blocks[HP_PTRS_IN_NOD]; /* pointers to HP_PTRS or records */
} HP_PTRS;
struct st_level_info
{
/* Number of unused slots in *last_blocks HP_PTRS block (0 for 0th level) */
uint free_ptrs_in_block;
/*
Maximum number of records that can be 'contained' inside of each element
of last_blocks array. For level 0 - 1, for level 1 - HP_PTRS_IN_NOD, for
level 2 - HP_PTRS_IN_NOD^2 and so forth.
*/
ulong records_under_level;
/*
Ptr to last allocated HP_PTRS (or records buffer for level 0) on this
level.
*/
HP_PTRS *last_blocks;
};
/*
Heap table records and hash index entries are stored in HP_BLOCKs.
HP_BLOCK is used as a 'growable array' of fixed-size records. Size of record
is recbuffer bytes.
The internal representation is as follows:
HP_BLOCK is a hierarchical structure of 'blocks'.
A block at level 0 is an array records_in_block records.
A block at higher level is an HP_PTRS structure with pointers to blocks at
lower levels.
At the highest level there is one top block. It is stored in HP_BLOCK::root.
See hp_find_block for a description of how record pointer is obtained from
its index.
See hp_get_new_block
*/
typedef struct st_heap_block
{
HP_PTRS *root; /* Top-level block */
struct st_level_info level_info[HP_MAX_LEVELS+1];
uint levels; /* number of used levels */
uint recbuffer; /* Length of one saved record */
ulong records_in_block; /* Records in one heap-block */
ulong last_allocated; /* number of records there is allocated space for */
size_t alloc_size; /* Allocate blocks of this size */
} HP_BLOCK;
struct st_heap_info; /* For reference */
typedef struct st_hp_keydef /* Key definition with open */
{
uint flag; /* HA_NOSAME | HA_NULL_PART_KEY */
uint keysegs; /* Number of key-segment */
uint length; /* Length of key (automatic) */
uint8 algorithm; /* HASH / BTREE */
HA_KEYSEG *seg;
HP_BLOCK block; /* Where keys are saved */
/*
Number of buckets used in hash table. Used only to provide
#records estimates for heap key scans.
*/
ha_rows hash_buckets;
TREE rb_tree;
int (*write_key)(struct st_heap_info *info, struct st_hp_keydef *keyinfo,
const uchar *record, uchar *recpos);
int (*delete_key)(struct st_heap_info *info, struct st_hp_keydef *keyinfo,
const uchar *record, uchar *recpos, int flag);
uint (*get_key_length)(struct st_hp_keydef *keydef, const uchar *key);
} HP_KEYDEF;
typedef struct st_heap_share
{
HP_BLOCK block;
HP_KEYDEF *keydef;
ulonglong data_length,index_length,max_table_size;
ulonglong auto_increment;
ulong min_records,max_records; /* Params to open */
ulong records; /* records */
ulong blength; /* records rounded up to 2^n */
ulong deleted; /* Deleted records in database */
uint key_stat_version; /* version to indicate insert/delete */
uint key_version; /* Updated on key change */
uint file_version; /* Update on clear */
uint reclength; /* Length of one record */
uint visible; /* Offset to the visible/deleted mark */
uint changed;
uint keys,max_key_length;
uint currently_disabled_keys; /* saved value from "keys" when disabled */
uint open_count;
uchar *del_link; /* Link to next block with del. rec */
char * name; /* Name of "memory-file" */
time_t create_time;
THR_LOCK lock;
my_bool delete_on_close;
my_bool internal; /* Internal temporary table */
LIST open_list;
uint auto_key;
uint auto_key_type; /* real type of the auto key segment */
} HP_SHARE;
struct st_hp_hash_info;
typedef struct st_heap_info
{
HP_SHARE *s;
uchar *current_ptr;
struct st_hp_hash_info *current_hash_ptr;
ulong current_record,next_block;
int lastinx,errkey;
int mode; /* Mode of file (READONLY..) */
uint opt_flag,update;
uchar *lastkey; /* Last used key with rkey */
uchar *recbuf; /* Record buffer for rb-tree keys */
enum ha_rkey_function last_find_flag;
TREE_ELEMENT *parents[MAX_TREE_HEIGHT+1];
TREE_ELEMENT **last_pos;
uint key_version; /* Version at last read */
uint file_version; /* Version at scan */
uint lastkey_len;
my_bool implicit_emptied;
THR_LOCK_DATA lock;
LIST open_list;
} HP_INFO;
typedef struct st_heap_create_info
{
HP_KEYDEF *keydef;
uint auto_key; /* keynr [1 - maxkey] for auto key */
uint auto_key_type;
uint keys;
uint reclength;
ulong max_records;
ulong min_records;
ulonglong max_table_size;
ulonglong auto_increment;
my_bool with_auto_increment;
my_bool internal_table;
/*
TRUE if heap_create should 'pin' the created share by setting
open_count to 1. Is only looked at if not internal_table.
*/
my_bool pin_share;
} HP_CREATE_INFO;
/* Prototypes for heap-functions */
extern HP_INFO *heap_open(const char *name, int mode);
extern HP_INFO *heap_open_from_share(HP_SHARE *share, int mode);
extern HP_INFO *heap_open_from_share_and_register(HP_SHARE *share, int mode);
extern void heap_release_share(HP_SHARE *share, my_bool internal_table);
extern int heap_close(HP_INFO *info);
extern int heap_write(HP_INFO *info,const uchar *buff);
extern int heap_update(HP_INFO *info,const uchar *old,const uchar *newdata);
extern int heap_rrnd(HP_INFO *info,uchar *buf,uchar *pos);
extern int heap_scan_init(HP_INFO *info);
extern int heap_scan(HP_INFO *info, uchar *record);
extern int heap_delete(HP_INFO *info,const uchar *buff);
extern int heap_info(HP_INFO *info,HEAPINFO *x,int flag);
extern int heap_create(const char *name,
HP_CREATE_INFO *create_info, HP_SHARE **share,
my_bool *created_new_share);
extern int heap_delete_table(const char *name);
extern void heap_drop_table(HP_INFO *info);
extern int heap_extra(HP_INFO *info,enum ha_extra_function function);
extern int heap_reset(HP_INFO *info);
extern int heap_rename(const char *old_name,const char *new_name);
extern int heap_panic(enum ha_panic_function flag);
extern int heap_rsame(HP_INFO *info,uchar *record,int inx);
extern int heap_rnext(HP_INFO *info,uchar *record);
extern int heap_rprev(HP_INFO *info,uchar *record);
extern int heap_rfirst(HP_INFO *info,uchar *record,int inx);
extern int heap_rlast(HP_INFO *info,uchar *record,int inx);
extern void heap_clear(HP_INFO *info);
extern void heap_clear_keys(HP_INFO *info);
extern int heap_disable_indexes(HP_INFO *info);
extern int heap_enable_indexes(HP_INFO *info);
extern int heap_indexes_are_disabled(HP_INFO *info);
extern void heap_update_auto_increment(HP_INFO *info, const uchar *record);
ha_rows hp_rb_records_in_range(HP_INFO *info, int inx,
const key_range *min_key,
const key_range *max_key);
int hp_panic(enum ha_panic_function flag);
int heap_rkey(HP_INFO *info, uchar *record, int inx, const uchar *key,
key_part_map keypart_map, enum ha_rkey_function find_flag);
extern uchar * heap_find(HP_INFO *info,int inx,const uchar *key);
extern int heap_check_heap(const HP_INFO *info, my_bool print_status);
extern uchar *heap_position(HP_INFO *info);
/* The following is for programs that uses the old HEAP interface where
pointer to rows where a long instead of a (uchar*).
*/
#if defined(WANT_OLD_HEAP_VERSION) || defined(OLD_HEAP_VERSION)
extern int heap_rrnd_old(HP_INFO *info,uchar *buf,ulong pos);
extern ulong heap_position_old(HP_INFO *info);
#endif
#ifdef OLD_HEAP_VERSION
typedef ulong HEAP_PTR;
#define heap_position(A) heap_position_old(A)
#define heap_rrnd(A,B,C) heap_rrnd_old(A,B,C)
#else
typedef uchar *HEAP_PTR;
#endif
#ifdef __cplusplus
}
#endif
#endif
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