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Removed the server option --stat-tables.

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Renamed the system variable optimizer_use_stat_tables to use_stat_tables.
This variable now has only 3 possible values:
'never', 'complementary', 'preferably'.
If the server has been launched with
--use-stat-tables='complementary'|'preferably'
then the statictics tables can be employed by the optimizer and by the
ANALYZE command.
This commit is contained in:
Igor Babaev
2012-06-02 17:19:01 -07:00
parent 2ee14ef9c3
commit f549f495f7
18 changed files with 244 additions and 295 deletions
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20
sql/sql_statistics.cc
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@ -28,13 +28,13 @@
#include "sql_statistics.h"
/*
The system variable 'optimizer_use_stat_tables' can take one of the
The system variable 'use_stat_tables' can take one of the
following values:
"never", "complementary", "preferably", "exclusively".
If the values of the variable 'optimizer_use_stat_tables' is set to
"never", "complementary", "preferably".
If the values of the variable 'use_stat_tables' is set to
"never then any statistical data from the persistent statistical tables
is ignored by the optimizer.
If the value of the variable 'optimizer_use_stat_tables' is set to
If the value of the variable 'use_stat_tables' is set to
"complementary" then a particular statistical characteristic is used
by the optimizer only if the database engine does not provide similar
statistics. For example, 'nulls_ratio' for table columns currently
@ -43,17 +43,13 @@
'avg_frequency' for any index prefix from the statistical tables since
the a similar statistical characteristic 'records_per_key' can be
requested from the database engine.
If the value the variable 'optimizer_use_stat_tables' is set to
If the value the variable 'use_stat_tables' is set to
"preferably" the optimizer uses a particular statistical data only if
it can't be found in the statistical data.
If the value of the variable 'optimizer_use_stat_tables' is set to
"exclusively" the optimizer never uses statistical data that can be
returned by the database engine Only statistical data from the
statistical tables is used.
If an ANALYZE command is executed then it results in collecting
statistical data for the tables specified by the command and storing
the collected statistics in the persistent statistical tables only
when the value of the variable 'optimizer_use_stat_tables' is not
when the value of the variable 'use_stat_tables' is not
equal to "never".
*/
@ -1650,14 +1646,14 @@ int read_statistics_for_table(THD *thd, TABLE *table)
table The table to set statistics for
@details
Depending on the value of thd->variables.optimizer_use_stat_tables
Depending on the value of thd->variables.use_stat_tables
the function performs the settings for the table that will control
from where the statistical data used by the optimizer will be taken.
*/
void set_statistics_for_table(THD *thd, TABLE *table)
{
uint use_stat_table_mode= thd->variables.optimizer_use_stat_tables;
uint use_stat_table_mode= thd->variables.use_stat_tables;
table->used_stat_records=
(use_stat_table_mode <= 1 || table->read_stat.cardinality_is_null) ?
table->file->stats.records : table->read_stat.cardinality;