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Added keyread_time() to HEAP

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The default keyread_time() was optimized for blocks and not suitable for
HEAP. The effect was the HEAP prefered table scans over ranges for btree
indexes.
Fixed also get_sweep_read_cost() for HEAP tables.
This commit is contained in:
Monty
2020-03-05 14:10:03 +02:00
parent a24d0926b9
commit c037cdadf4
6 changed files with 15 additions and 11 deletions
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2
mysql-test/main/endspace.result
View File

@ -145,8 +145,8 @@ teststring
teststring
select * from t1 where text1='teststring' or text1 >= 'teststring\t';
text1
teststring
teststring
teststring
select * from t1 order by text1;
text1
nothing

2
mysql-test/suite/heap/heap_btree.result
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@ -178,7 +178,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range btn btn 10 NULL 1 Using where
explain select * from t1 where btn like "h%";
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL btn NULL NULL NULL # Using where
1 SIMPLE t1 range btn btn 10 NULL # Using where
explain select * from t1 where btn like "a%";
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range btn btn 10 NULL 1 Using where

8
mysql-test/suite/heap/heap_hash.result
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@ -428,14 +428,14 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uniq_id uniq_id 8 NULL 2 Using where
select 0+a from t1 where a in (869751,736494,226312,802616,728912);
0+a
869751
736494
226312
802616
728912
736494
802616
869751
explain select 0+a from t1 where a in (869751,736494,226312,802616,728912);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL uniq_id NULL NULL NULL 5 Using where
1 SIMPLE t1 range uniq_id uniq_id 8 NULL 5 Using where
drop table t1;
End of 5.3 tests
#

6
sql/handler.cc
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@ -2675,11 +2675,13 @@ double handler::keyread_time(uint index, uint ranges, ha_rows rows)
size_t len= table->key_info[index].key_length + ref_length;
if (index == table->s->primary_key && table->file->primary_key_is_clustered())
len= table->s->stored_rec_length;
uint keys_per_block= (uint) (stats.block_size/2.0/len+1);
ulonglong blocks= !rows ? 0 : (rows-1) / keys_per_block + 1;
double cost= (double)rows*len/(stats.block_size+1)*IDX_BLOCK_COPY_COST;
if (ranges)
{
uint keys_per_block= (uint) (stats.block_size/2.0/len+1);
ulonglong blocks= !rows ? 0 : (rows-1) / keys_per_block + 1;
cost+= blocks;
}
return cost;
}

3
sql/opt_range.cc
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@ -4897,7 +4897,8 @@ double get_sweep_read_cost(const PARAM *param, ha_rows records)
{
double result;
DBUG_ENTER("get_sweep_read_cost");
if (param->table->file->primary_key_is_clustered())
if (param->table->file->primary_key_is_clustered() ||
param->table->file->stats.block_size == 0 /* HEAP */)
{
/*
We are using the primary key to find the rows.

5
storage/heap/ha_heap.h
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@ -65,8 +65,9 @@ public:
double scan_time()
{ return (double) (stats.records+stats.deleted) / 20.0+10; }
double read_time(uint index, uint ranges, ha_rows rows)
{ return (double) rows / 20.0+1; }
{ return (double) rows / 20.0+1; }
double keyread_time(uint index, uint ranges, ha_rows rows)
{ return (double) rows / 20.0+1; }
int open(const char *name, int mode, uint test_if_locked);
int close(void);
void set_keys_for_scanning(void);