1berry/MariaDB-server
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix for bug#5138: hash indexes on heap tables support statistics.

Browse Source 
KEY::rec_per_key is updated every time 1/HEAP_STATS_UPDATE_THRESHOLD part of table records has been changed.
This commit is contained in:
sergefp@mysql.com 2004-09-08 02:07:53 +04:00
parent 15eb33ab44
commit 2c9d2cf671
14 changed files with 386 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
heap/_check.c
View File

@ -102,9 +102,11 @@ static int check_one_key(HP_KEYDEF *keydef, uint keynr, ulong records,
int error;
uint i,found,max_links,seek,links;
uint rec_link; /* Only used with debugging */
uint hash_buckets_found;
HASH_INFO *hash_info;
error=0;
hash_buckets_found= 0;
for (i=found=max_links=seek=0 ; i < records ; i++)
{
hash_info=hp_find_hash(&keydef->block,i);
@ -128,21 +130,32 @@ static int check_one_key(HP_KEYDEF *keydef, uint keynr, ulong records,
found++;
}
if (links > max_links) max_links=links;
hash_buckets_found++;
}
}
if (found != records)
{
DBUG_PRINT("error",("Found %ld of %ld records"));
DBUG_PRINT("error",("Found %ld of %ld records", found, records));
error=1;
}
if (keydef->hash_buckets != hash_buckets_found)
{
DBUG_PRINT("error",("Found %ld buckets, stats shows %ld buckets",
hash_buckets_found, keydef->hash_buckets));
error=1;
}
DBUG_PRINT("info",
("records: %ld seeks: %d max links: %d hitrate: %.2f",
("records: %ld seeks: %d max links: %d hitrate: %.2f "
"buckets: %d",
records,seek,max_links,
(float) seek / (float) (records ? records : 1)));
(float) seek / (float) (records ? records : 1),
hash_buckets_found));
if (print_status)
printf("Key: %d records: %ld seeks: %d max links: %d hitrate: %.2f\n",
printf("Key: %d records: %ld seeks: %d max links: %d "
"hitrate: %.2f buckets: %d\n",
keynr, records, seek, max_links,
(float) seek / (float) (records ? records : 1));
(float) seek / (float) (records ? records : 1),
hash_buckets_found);
return error;
}

1
heap/hp_clear.c
View File

@ -97,6 +97,7 @@ void hp_clear_keys(HP_SHARE *info)
VOID(hp_free_level(block,block->levels,block->root,(byte*) 0));
block->levels=0;
block->last_allocated=0;
keyinfo->hash_buckets= 0;
}
}
info->index_length=0;

1
heap/hp_create.c
View File

@ -128,6 +128,7 @@ int heap_create(const char *name, uint keys, HP_KEYDEF *keydef,
max_records);
keyinfo->delete_key= hp_delete_key;
keyinfo->write_key= hp_write_key;
keyinfo->hash_buckets= 0;
}
}
share->min_records= min_records;

8
heap/hp_delete.c
View File

@ -151,6 +151,8 @@ int hp_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
pos->ptr_to_rec=empty->ptr_to_rec;
pos->next_key=empty->next_key;
}
else
keyinfo->hash_buckets--;
if (empty == lastpos) /* deleted last hash key */
DBUG_RETURN (0);
@ -187,7 +189,11 @@ int hp_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
}
pos3= pos; /* Link pos->next after lastpos */
}
else pos3= 0; /* Different positions merge */
else
{
pos3= 0; /* Different positions merge */
keyinfo->hash_buckets--;
}
empty[0]=lastpos[0];
hp_movelink(pos3, empty, pos->next_key);

20
heap/hp_hash.c
View File

@ -196,7 +196,18 @@ byte *hp_search_next(HP_INFO *info, HP_KEYDEF *keyinfo, const byte *key,
}
/* Calculate pos according to keys */
/*
Calculate position number for hash value.
SYNOPSIS
hp_mask()
hashnr Hash value
buffmax Value such that
2^(n-1) < maxlength <= 2^n = buffmax
maxlength
RETURN
Array index, in [0..maxlength)
*/
ulong hp_mask(ulong hashnr, ulong buffmax, ulong maxlength)
{
@ -205,7 +216,12 @@ ulong hp_mask(ulong hashnr, ulong buffmax, ulong maxlength)
}
/* Change link from pos to new_link */
/*
Change
next_link -> ... -> X -> pos
to
next_link -> ... -> X -> newlink
*/
void hp_movelink(HASH_INFO *pos, HASH_INFO *next_link, HASH_INFO *newlink)
{

25
heap/hp_write.c
View File

@ -36,7 +36,7 @@ int heap_write(HP_INFO *info, const byte *record)
byte *pos;
HP_SHARE *share=info->s;
DBUG_ENTER("heap_write");
printf("heap_write\n");
#ifndef DBUG_OFF
if (info->mode & O_RDONLY)
{
@ -180,15 +180,31 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
DBUG_RETURN(-1); /* No more memory */
halfbuff= (long) share->blength >> 1;
pos= hp_find_hash(&keyinfo->block,(first_index=share->records-halfbuff));
/*
We're about to add one more hash position, with hash_mask=#records.
Entries that should be relocated to that position are currently members
of the list that starts at #first_index position.
At #first_index position there may be either:
a) A list of items with hash_mask=first_index. The list contains
1) entries that should be relocated to the list that starts at new
position we're adding
2) entries that should be left in the list starting at #first_index
position
or
b) An entry with hashnr != first_index. We don't need to move it.
*/
if (pos != empty) /* If some records */
{
do
{
hashnr = hp_rec_hashnr(keyinfo, pos->ptr_to_rec);
if (flag == 0) /* First loop; Check if ok */
{
/* Bail out if we're dealing with case b) from above comment */
if (hp_mask(hashnr, share->blength, share->records) != first_index)
break;
}
if (!(hashnr & halfbuff))
{ /* Key will not move */
if (!(flag & LOWFIND))
@ -245,6 +261,9 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
}
}
while ((pos=pos->next_key));
if ((flag & (LOWFIND | HIGHFIND)) == (LOWFIND | HIGHFIND))
keyinfo->hash_buckets++;
if ((flag & (LOWFIND | LOWUSED)) == LOWFIND)
{
@ -265,6 +284,7 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
{
pos->ptr_to_rec=recpos;
pos->next_key=0;
keyinfo->hash_buckets++;
}
else
{
@ -280,6 +300,7 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
}
else
{
keyinfo->hash_buckets++;
pos->ptr_to_rec=recpos;
pos->next_key=0;
hp_movelink(pos, gpos, empty);

7
include/heap.h
View File

@ -87,6 +87,11 @@ typedef struct st_hp_keydef /* Key definition with open */
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 byte *record, byte *recpos);
@ -102,7 +107,7 @@ typedef struct st_heap_share
ulong min_records,max_records; /* Params to open */
ulong data_length,index_length;
uint records; /* records */
uint blength;
uint blength; /* records rounded up to 2^n */
uint deleted; /* Deleted records in database */
uint reclength; /* Length of one record */
uint changed;

8
mysql-test/r/heap.result
View File

@ -4,7 +4,7 @@ insert into t1 values(1,1),(2,2),(3,3),(4,4);
delete from t1 where a=1 or a=0;
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 PRIMARY 1 a NULL NULL NULL NULL HASH
t1 0 PRIMARY 1 a NULL 3 NULL NULL HASH
select * from t1;
a b
2 2
@ -169,7 +169,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL btn NULL NULL NULL 11 Using where
explain select * from t1 where btn="a" and new_col="a";
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref btn btn 11 const,const 10 Using where
1 SIMPLE t1 ref btn btn 11 const,const 2 Using where
drop table t1;
CREATE TABLE t1 (
a int default NULL,
@ -182,7 +182,7 @@ SELECT * FROM t1 WHERE a=NULL;
a b
explain SELECT * FROM t1 WHERE a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 5 const 10 Using where
1 SIMPLE t1 ref a a 5 const 1 Using where
SELECT * FROM t1 WHERE a<=>NULL;
a b
NULL 99
@ -204,7 +204,7 @@ key a (a)
INSERT INTO t1 VALUES (10), (10), (10);
EXPLAIN SELECT * FROM t1 WHERE a=10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 5 const 10 Using where
1 SIMPLE t1 ref a a 5 const 3 Using where
SELECT * FROM t1 WHERE a=10;
a
10

144
mysql-test/r/heap_hash.result
View File

@ -1,10 +1,10 @@
drop table if exists t1;
drop table if exists t1,t2;
create table t1 (a int not null,b int not null, primary key using HASH (a)) engine=heap comment="testing heaps" avg_row_length=100 min_rows=1 max_rows=100;
insert into t1 values(1,1),(2,2),(3,3),(4,4);
delete from t1 where a=1 or a=0;
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 PRIMARY 1 a NULL NULL NULL NULL HASH
t1 0 PRIMARY 1 a NULL 3 NULL NULL HASH
select * from t1;
a b
2 2
@ -169,7 +169,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL btn NULL NULL NULL 11 Using where
explain select * from t1 where btn="a" and new_col="a";
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref btn btn 11 const,const 10 Using where
1 SIMPLE t1 ref btn btn 11 const,const 2 Using where
drop table t1;
CREATE TABLE t1 (
a int default NULL,
@ -182,7 +182,7 @@ SELECT * FROM t1 WHERE a=NULL;
a b
explain SELECT * FROM t1 WHERE a IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 5 const 10 Using where
1 SIMPLE t1 ref a a 5 const 1 Using where
SELECT * FROM t1 WHERE a<=>NULL;
a b
NULL 99
@ -203,3 +203,139 @@ DELETE from t1 where a < 100;
SELECT * from t1;
a
DROP TABLE t1;
create table t1
(
a char(8) not null,
b char(20) not null,
c int not null,
key (a)
) engine=heap;
insert into t1 values ('aaaa', 'prefill-hash=5',0);
insert into t1 values ('aaab', 'prefill-hash=0',0);
insert into t1 values ('aaac', 'prefill-hash=7',0);
insert into t1 values ('aaad', 'prefill-hash=2',0);
insert into t1 values ('aaae', 'prefill-hash=1',0);
insert into t1 values ('aaaf', 'prefill-hash=4',0);
insert into t1 values ('aaag', 'prefill-hash=3',0);
insert into t1 values ('aaah', 'prefill-hash=6',0);
explain select * from t1 where a='aaaa';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 1 Using where
explain select * from t1 where a='aaab';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 1 Using where
explain select * from t1 where a='aaac';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 1 Using where
explain select * from t1 where a='aaad';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 1 Using where
insert into t1 select * from t1;
explain select * from t1 where a='aaaa';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaab';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaac';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaad';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
create table t2 as select * from t1;
delete from t1;
insert into t1 select * from t2;
explain select * from t1 where a='aaaa';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaab';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaac';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
explain select * from t1 where a='aaad';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 8 const 2 Using where
drop table t1, t2;
create table t1 (
id int unsigned not null primary key auto_increment,
name varchar(20) not null,
index heap_idx(name),
index btree_idx using btree(name)
) engine=heap;
create table t2 (
id int unsigned not null primary key auto_increment,
name varchar(20) not null,
index btree_idx using btree(name),
index heap_idx(name)
) engine=heap;
insert into t1 (name) values ('Matt'), ('Lilu'), ('Corbin'), ('Carly'),
('Suzy'), ('Hoppy'), ('Burrito'), ('Mimi'), ('Sherry'), ('Ben'), ('Phil'),
('Emily'), ('Mike');
insert into t2 select * from t1;
explain select * from t1 where name='matt';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref heap_idx,btree_idx heap_idx 20 const 1 Using where
explain select * from t2 where name='matt';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref btree_idx,heap_idx btree_idx 20 const 1 Using where
explain select * from t1 where name='Lilu';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref heap_idx,btree_idx heap_idx 20 const 1 Using where
explain select * from t2 where name='Lilu';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref btree_idx,heap_idx btree_idx 20 const 1 Using where
explain select * from t1 where name='Phil';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref heap_idx,btree_idx heap_idx 20 const 1 Using where
explain select * from t2 where name='Phil';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref btree_idx,heap_idx btree_idx 20 const 1 Using where
explain select * from t1 where name='Lilu';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref heap_idx,btree_idx heap_idx 20 const 1 Using where
explain select * from t2 where name='Lilu';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref btree_idx,heap_idx btree_idx 20 const 1 Using where
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
select count(*) from t1 where name='Matt';
count(*)
7
explain select * from t1 ignore index (btree_idx) where name='matt';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref heap_idx heap_idx 20 const 7 Using where
show index from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 PRIMARY 1 id NULL 91 NULL NULL HASH
t1 1 heap_idx 1 name NULL 15 NULL NULL HASH
t1 1 btree_idx 1 name A NULL NULL NULL BTREE
flush tables;
show index from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 PRIMARY 1 id NULL 91 NULL NULL HASH
t1 1 heap_idx 1 name NULL 13 NULL NULL HASH
t1 1 btree_idx 1 name A NULL NULL NULL BTREE
create table t3
(
a varchar(20) not null,
b varchar(20) not null,
key (a,b)
) engine=heap;
insert into t3 select name, name from t1;
show index from t3;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t3 1 a 1 a NULL NULL NULL NULL HASH
t3 1 a 2 b NULL 15 NULL NULL HASH
flush tables;
show index from t3;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t3 1 a 1 a NULL NULL NULL NULL HASH
t3 1 a 2 b NULL 13 NULL NULL HASH
drop table t1,t2;

2
mysql-test/r/myisam.result
View File

@ -543,7 +543,7 @@ Warnings:
Note 1031 Table storage engine for 't1' doesn't have this option
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 1 a 1 a NULL NULL NULL NULL YES HASH
t1 1 a 1 a NULL 1000 NULL NULL YES HASH
drop table t1,t2;
create table t1 ( a tinytext, b char(1), index idx (a(1),b) );
insert into t1 values (null,''), (null,'');

104
mysql-test/t/heap_hash.test
View File

@ -3,7 +3,7 @@
#
--disable_warnings
drop table if exists t1;
drop table if exists t1,t2;
--enable_warnings
create table t1 (a int not null,b int not null, primary key using HASH (a)) engine=heap comment="testing heaps" avg_row_length=100 min_rows=1 max_rows=100;
@ -141,3 +141,105 @@ INSERT into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11);
DELETE from t1 where a < 100;
SELECT * from t1;
DROP TABLE t1;
#
# Hash index # records estimate test
#
create table t1
(
a char(8) not null,
b char(20) not null,
c int not null,
key (a)
) engine=heap;
insert into t1 values ('aaaa', 'prefill-hash=5',0);
insert into t1 values ('aaab', 'prefill-hash=0',0);
insert into t1 values ('aaac', 'prefill-hash=7',0);
insert into t1 values ('aaad', 'prefill-hash=2',0);
insert into t1 values ('aaae', 'prefill-hash=1',0);
insert into t1 values ('aaaf', 'prefill-hash=4',0);
insert into t1 values ('aaag', 'prefill-hash=3',0);
insert into t1 values ('aaah', 'prefill-hash=6',0);
explain select * from t1 where a='aaaa';
explain select * from t1 where a='aaab';
explain select * from t1 where a='aaac';
explain select * from t1 where a='aaad';
insert into t1 select * from t1;
explain select * from t1 where a='aaaa';
explain select * from t1 where a='aaab';
explain select * from t1 where a='aaac';
explain select * from t1 where a='aaad';
# Check if delete_all_rows() updates #hash_buckets
create table t2 as select * from t1;
delete from t1;
insert into t1 select * from t2;
explain select * from t1 where a='aaaa';
explain select * from t1 where a='aaab';
explain select * from t1 where a='aaac';
explain select * from t1 where a='aaad';
drop table t1, t2;
# Btree and hash index use costs.
create table t1 (
id int unsigned not null primary key auto_increment,
name varchar(20) not null,
index heap_idx(name),
index btree_idx using btree(name)
) engine=heap;
create table t2 (
id int unsigned not null primary key auto_increment,
name varchar(20) not null,
index btree_idx using btree(name),
index heap_idx(name)
) engine=heap;
insert into t1 (name) values ('Matt'), ('Lilu'), ('Corbin'), ('Carly'),
('Suzy'), ('Hoppy'), ('Burrito'), ('Mimi'), ('Sherry'), ('Ben'), ('Phil'),
('Emily'), ('Mike');
insert into t2 select * from t1;
explain select * from t1 where name='matt';
explain select * from t2 where name='matt';
explain select * from t1 where name='Lilu';
explain select * from t2 where name='Lilu';
explain select * from t1 where name='Phil';
explain select * from t2 where name='Phil';
explain select * from t1 where name='Lilu';
explain select * from t2 where name='Lilu';
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
insert into t1 (name) select name from t2;
select count(*) from t1 where name='Matt';
explain select * from t1 ignore index (btree_idx) where name='matt';
show index from t1;
flush tables;
show index from t1;
create table t3
(
a varchar(20) not null,
b varchar(20) not null,
key (a,b)
) engine=heap;
insert into t3 select name, name from t1;
show index from t3;
flush tables;
show index from t3;
drop table t1,t2;

56
sql/ha_heap.cc
View File

@ -30,6 +30,12 @@
const char **ha_heap::bas_ext() const
{ static const char *ext[1]= { NullS }; return ext; }
/*
Hash index statistics is updated (copied from HP_KEYDEF::hash_buckets to
rec_per_key) after 1/HEAP_STATS_UPDATE_THRESHOLD records have been inserted/
updated/deleted. delete_all_rows() and table flush cause immediate update.
*/
#define HEAP_STATS_UPDATE_THRESHOLD 10
int ha_heap::open(const char *name, int mode, uint test_if_locked)
{
@ -48,6 +54,8 @@ int ha_heap::open(const char *name, int mode, uint test_if_locked)
{
/* Initialize variables for the opened table */
set_keys_for_scanning();
if (table->tmp_table == NO_TMP_TABLE)
update_key_stats();
}
return (file ? 0 : 1);
}
@ -84,28 +92,59 @@ void ha_heap::set_keys_for_scanning(void)
}
}
void ha_heap::update_key_stats()
{
printf("update_key_stats\n");
for (uint i= 0; i < table->keys; i++)
{
KEY *key=table->key_info+i;
if (key->algorithm != HA_KEY_ALG_BTREE)
{
ha_rows hash_buckets= file->s->keydef[i].hash_buckets;
key->rec_per_key[key->key_parts-1]=
hash_buckets ? file->s->records/hash_buckets : 0;
}
}
records_changed= 0;
}
int ha_heap::write_row(byte * buf)
{
int res;
statistic_increment(ha_write_count,&LOCK_status);
if (table->timestamp_default_now)
update_timestamp(buf+table->timestamp_default_now-1);
if (table->next_number_field && buf == table->record[0])
update_auto_increment();
return heap_write(file,buf);
res= heap_write(file,buf);
if (!res && table->tmp_table == NO_TMP_TABLE &&
++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
update_key_stats();
return res;
}
int ha_heap::update_row(const byte * old_data, byte * new_data)
{
int res;
statistic_increment(ha_update_count,&LOCK_status);
if (table->timestamp_on_update_now)
update_timestamp(new_data+table->timestamp_on_update_now-1);
return heap_update(file,old_data,new_data);
res= heap_update(file,old_data,new_data);
if (!res && table->tmp_table == NO_TMP_TABLE &&
++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
update_key_stats();
return res;
}
int ha_heap::delete_row(const byte * buf)
{
int res;
statistic_increment(ha_delete_count,&LOCK_status);
return heap_delete(file,buf);
res= heap_delete(file,buf);
if (!res && table->tmp_table == NO_TMP_TABLE &&
++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
update_key_stats();
return res;
}
int ha_heap::index_read(byte * buf, const byte * key, uint key_len,
@ -227,6 +266,8 @@ int ha_heap::extra(enum ha_extra_function operation)
int ha_heap::delete_all_rows()
{
heap_clear(file);
if (table->tmp_table == NO_TMP_TABLE)
update_key_stats();
return 0;
}
@ -383,7 +424,14 @@ ha_rows ha_heap::records_in_range(uint inx, key_range *min_key,
min_key->flag != HA_READ_KEY_EXACT ||
max_key->flag != HA_READ_AFTER_KEY)
return HA_POS_ERROR; // Can only use exact keys
return 10; // Good guess
else
{
ha_rows records= file->s->records;
if (!records)
return 0;
ha_rows res= records / file->s->keydef[inx].hash_buckets;
return res ? res : 1;
}
}

10
sql/ha_heap.h
View File

@ -27,9 +27,10 @@ class ha_heap: public handler
{
HP_INFO *file;
key_map btree_keys;
public:
ha_heap(TABLE *table): handler(table), file(0) {}
/* number of records changed since last statistics update */
uint records_changed;
public:
ha_heap(TABLE *table): handler(table), file(0), records_changed(0) {}
~ha_heap() {}
const char *table_type() const { return "HEAP"; }
const char *index_type(uint inx)
@ -91,5 +92,6 @@ class ha_heap: public handler
THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
enum thr_lock_type lock_type);
private:
void update_key_stats();
};

7
sql/structs.h
View File

@ -89,7 +89,12 @@ typedef struct st_key {
enum ha_key_alg algorithm;
KEY_PART_INFO *key_part;
char *name; /* Name of key */
ulong *rec_per_key; /* Key part distribution */
/*
Array of AVG(#records with the same field value) for 1st ... Nth key part.
0 means 'not known'.
For temporary heap tables this member is NULL.
*/
ulong *rec_per_key;
union {
int bdb_return_if_eq;
} handler;