Skip to content

M
MariaDB
Commit 1cc999fb authored by sergefp@mysql.com's avatar sergefp@mysql.com
Browse files
Options

Merge spetrunia@bk-internal.mysql.com:/home/bk/mysql-4.1 

into mysql.com:/dbdata/psergey/mysql-4.1-heap-bug
parents a69ddb03 a0ba02d7
Show whitespace changes
Inline Side-by-side
Showing with 558 additions and 53 deletions
heap/_check.c
View file @ 1cc999fb
......@@ -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;
}
......
heap/hp_block.c
View file @ 1cc999fb
......@@ -18,12 +18,19 @@
#include "heapdef.h"
/* Find record according to record-position */
/*
Find record according to record-position.
The record is located by factoring position number pos into (p_0, p_1, ...)
such that
pos = SUM_i(block->level_info[i].records_under_level * p_i)
{p_0, p_1, ...} serve as indexes to descend the blocks tree.
*/
byte *hp_find_block(HP_BLOCK *block, ulong pos)
{
reg1 int i;
reg3 HP_PTRS *ptr;
reg3 HP_PTRS *ptr; /* block base ptr */
for (i=block->levels-1, ptr=block->root ; i > 0 ; i--)
{
......@@ -34,8 +41,18 @@ byte *hp_find_block(HP_BLOCK *block, ulong pos)
}
/* get one new block-of-records. Alloc ptr to block if neaded */
/* Interrupts are stopped to allow ha_panic in interrupts */
/*
Get one new block-of-records. Alloc ptr to block if needed
SYNOPSIS
hp_get_new_block()
block HP_BLOCK tree-like block
alloc_length OUT Amount of memory allocated from the heap
Interrupts are stopped to allow ha_panic in interrupts
RETURN
0 OK
1 Out of memory
*/
int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
{
......@@ -46,6 +63,18 @@ int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
if (block->level_info[i].free_ptrs_in_block)
break;
/*
Allocate space for leaf block plus space for upper level blocks up to
first level that has a free slot to put the pointer.
In some cases we actually allocate more then we need:
Consider e.g. a situation where we have one level 1 block and one level 0
block, the level 0 block is full and this function is called. We only
need a leaf block in this case. Nevertheless, we will get here with i=1
and will also allocate sizeof(HP_PTRS) for non-leaf block and will never
use this space.
This doesn't add much overhead - with current values of sizeof(HP_PTRS)
and my_default_record_cache_size we get about 1/128 unused memory.
*/
*alloc_length=sizeof(HP_PTRS)*i+block->records_in_block* block->recbuffer;
if (!(root=(HP_PTRS*) my_malloc(*alloc_length,MYF(0))))
return 1;
......@@ -60,21 +89,33 @@ int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
dont_break(); /* Dont allow SIGHUP or SIGINT */
if ((uint) i == block->levels)
{
/* Adding a new level on top of the existing ones. */
block->levels=i+1;
/*
Use first allocated HP_PTRS as a top-level block. Put the current
block tree into the first slot of a new top-level block.
*/
block->level_info[i].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
((HP_PTRS**) root)[0]= block->root;
block->root=block->level_info[i].last_blocks= root++;
}
/* Occupy the free slot we've found at level i */
block->level_info[i].last_blocks->
blocks[HP_PTRS_IN_NOD - block->level_info[i].free_ptrs_in_block--]=
(byte*) root;
/* Add a block subtree with each node having one left-most child */
for (j=i-1 ; j >0 ; j--)
{
block->level_info[j].last_blocks= root++;
block->level_info[j].last_blocks->blocks[0]=(byte*) root;
block->level_info[j].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
}
/*
root now points to last (block->records_in_block* block->recbuffer)
allocated bytes. Use it as a leaf block.
*/
block->level_info[0].last_blocks= root;
allow_break(); /* Allow SIGHUP & SIGINT */
}
......
heap/hp_clear.c
View file @ 1cc999fb
......@@ -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;
......
heap/hp_create.c
View file @ 1cc999fb
......@@ -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;
......
heap/hp_delete.c
View file @ 1cc999fb
......@@ -97,8 +97,8 @@ int hp_rb_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
flag Is set if we want's to correct info->current_ptr
RETURN
0 ok
# error number
0 Ok
other Error code
*/
int hp_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
......@@ -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);
......
heap/hp_hash.c
View file @ 1cc999fb
......@@ -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)
{
......
heap/hp_write.c
View file @ 1cc999fb
......@@ -36,7 +36,6 @@ int heap_write(HP_INFO *info, const byte *record)
byte *pos;
HP_SHARE *share=info->s;
DBUG_ENTER("heap_write");
#ifndef DBUG_OFF
if (info->mode & O_RDONLY)
{
......@@ -160,7 +159,31 @@ static byte *next_free_record_pos(HP_SHARE *info)
block_pos*info->block.recbuffer);
}
/* Write a hash-key to the hash-index */
/*
Write a hash-key to the hash-index
SYNOPSIS
info Heap table info
keyinfo Key info
record Table record to added
recpos Memory buffer where the table record will be stored if added
successfully
NOTE
Hash index uses HP_BLOCK structure as a 'growable array' of HASH_INFO
structs. Array size == number of entries in hash index.
hp_mask(hp_rec_hashnr()) maps hash entries values to hash array positions.
If there are several hash entries with the same hash array position P,
they are connected in a linked list via HASH_INFO::next_key. The first
list element is located at position P, next elements are located at
positions for which there is no record that should be located at that
position. The order of elements in the list is arbitrary.
RETURN
0 - OK
-1 - Out of memory
HA_ERR_FOUND_DUPP_KEY - Duplicate record on unique key. The record was
still added and the caller must call hp_delete_key for it.
*/
int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
const byte *record, byte *recpos)
......@@ -181,18 +204,53 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
halfbuff= (long) share->blength >> 1;
pos= hp_find_hash(&keyinfo->block,(first_index=share->records-halfbuff));
/*
We're about to add one more hash array position, with hash_mask=#records.
The number of hash positions will change and some entries might need to
be relocated to the newly added position. Those entries are currently
members of the list that starts at #first_index position (this is
guaranteed by properties of hp_mask(hp_rec_hashnr(X)) mapping function)
At #first_index position currently there may be either:
a) An entry with hashnr != first_index. We don't need to move it.
or
b) A list of items with hash_mask=first_index. The list contains entries
of 2 types:
1) entries that should be relocated to the list that starts at new
position we're adding ('uppper' list)
2) entries that should be left in the list starting at #first_index
position ('lower' list)
*/
if (pos != empty) /* If some records */
{
do
{
hashnr = hp_rec_hashnr(keyinfo, pos->ptr_to_rec);
if (flag == 0) /* First loop; Check if ok */
if (flag == 0)
{
/*
First loop, bail out if we're dealing with case a) from above
comment
*/
if (hp_mask(hashnr, share->blength, share->records) != first_index)
break;
}
/*
flag & LOWFIND - found a record that should be put into lower position
flag & LOWUSED - lower position occupied by the record
Same for HIGHFIND and HIGHUSED and 'upper' position
gpos - ptr to last element in lower position's list
gpos2 - ptr to last element in upper position's list
ptr_to_rec - ptr to last entry that should go into lower list.
ptr_to_rec2 - same for upper list.
*/
if (!(hashnr & halfbuff))
{ /* Key will not move */
{
/* Key should be put into 'lower' list */
if (!(flag & LOWFIND))
{
/* key is the first element to go into lower position */
if (flag & HIGHFIND)
{
flag=LOWFIND | HIGHFIND;
......@@ -203,16 +261,21 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
}
else
{
flag=LOWFIND | LOWUSED; /* key isn't changed */
/*
We can only get here at first iteration: key is at 'lower'
position pos and should be left here.
*/
flag=LOWFIND | LOWUSED;
gpos=pos;
ptr_to_rec=pos->ptr_to_rec;
}
}
else
{
/* Already have another key for lower position */
if (!(flag & LOWUSED))
{
/* Change link of previous LOW-key */
/* Change link of previous lower-list key */
gpos->ptr_to_rec=ptr_to_rec;
gpos->next_key=pos;
flag= (flag & HIGHFIND) | (LOWFIND | LOWUSED);
......@@ -222,19 +285,21 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
}
}
else
{ /* key will be moved */
{
/* key will be put into 'higher' list */
if (!(flag & HIGHFIND))
{
flag= (flag & LOWFIND) | HIGHFIND;
/* key shall be moved to the last (empty) position */
gpos2 = empty; empty=pos;
gpos2= empty;
empty= pos;
ptr_to_rec2=pos->ptr_to_rec;
}
else
{
if (!(flag & HIGHUSED))
{
/* Change link of previous hash-key and save */
/* Change link of previous upper-list key and save */
gpos2->ptr_to_rec=ptr_to_rec2;
gpos2->next_key=pos;
flag= (flag & LOWFIND) | (HIGHFIND | HIGHUSED);
......@@ -246,6 +311,15 @@ int hp_write_key(HP_INFO *info, HP_KEYDEF *keyinfo,
}
while ((pos=pos->next_key));
if ((flag & (LOWFIND | HIGHFIND)) == (LOWFIND | HIGHFIND))
{
/*
If both 'higher' and 'lower' list have at least one element, now
there are two hash buckets instead of one.
*/
keyinfo->hash_buckets++;
}
if ((flag & (LOWFIND | LOWUSED)) == LOWFIND)
{
gpos->ptr_to_rec=ptr_to_rec;
......@@ -265,6 +339,7 @@ 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 +355,7 @@ 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);
......
include/heap.h
View file @ 1cc999fb
......@@ -63,18 +63,48 @@ typedef struct st_heap_ptrs
struct st_level_info
{
uint free_ptrs_in_block,records_under_level;
HP_PTRS *last_blocks; /* pointers to HP_PTRS or records */
/* 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.
*/
uint records_under_level;
/*
Ptr to last allocated HP_PTRS (or records buffer for level 0) on this
level.
*/
HP_PTRS *last_blocks;
};
typedef struct st_heap_block /* The data is saved in 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;
HP_PTRS *root; /* Top-level block */
struct st_level_info level_info[HP_MAX_LEVELS+1];
uint levels;
uint records_in_block; /* Records in a heap-block */
uint levels; /* number of used levels */
uint records_in_block; /* Records in one heap-block */
uint recbuffer; /* Length of one saved record */
ulong last_allocated; /* Blocks allocated, used by keys */
ulong last_allocated; /* number of records there is allocated space for */
} HP_BLOCK;
struct st_heap_info; /* For referense */
......@@ -87,6 +117,11 @@ 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 +137,7 @@ 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;
......
mysql-test/r/heap.result
View file @ 1cc999fb
......@@ -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
......
mysql-test/r/heap_hash.result
View file @ 1cc999fb
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 +203,155 @@ 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 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
flush tables;
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 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
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;
flush tables;
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 13 NULL NULL HASH
t1 1 btree_idx 1 name A NULL NULL NULL BTREE
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
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
explain select * from t1 ignore key(btree_idx), t3 where t1.name='matt' and t3.a = concat('',t1.name) and t3.b=t1.name;
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
1 SIMPLE t3 ref a a 40 func,const 6 Using where
drop table t1, t2, t3;
mysql-test/r/myisam.result
View file @ 1cc999fb
......@@ -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,'');
......
mysql-test/t/heap_hash.test
View file @ 1cc999fb
......@@ -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 +141,113 @@ 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';
# a known effect: table reload causes statistics to be updated:
flush tables;
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;
flush tables;
select count(*) from t1 where name='Matt';
explain select * from t1 ignore index (btree_idx) where name='matt';
show index from t1;
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;
show index from t3;
# test rec_per_key use for joins.
explain select * from t1 ignore key(btree_idx), t3 where t1.name='matt' and t3.a = concat('',t1.name) and t3.b=t1.name;
drop table t1, t2, t3;
sql/ha_heap.cc
View file @ 1cc999fb
......@@ -30,6 +30,18 @@
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 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)
{
......@@ -48,6 +60,8 @@ 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 +98,58 @@ void ha_heap::set_keys_for_scanning(void)
}
}
void ha_heap::update_key_stats()
{
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_field_type & TIMESTAMP_AUTO_SET_ON_INSERT)
table->timestamp_field->set_time();
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_field_type & TIMESTAMP_AUTO_SET_ON_UPDATE)
table->timestamp_field->set_time();
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 +271,8 @@ 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;
}
......@@ -384,7 +430,8 @@ 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
return key->rec_per_key[key->key_parts-1];
}
......
sql/ha_heap.h
View file @ 1cc999fb
......@@ -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();
};
sql/structs.h
View file @ 1cc999fb
......@@ -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;
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7