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515b9ad05a
MDEV-28073 Slow query performance in MariaDB when using many table The idea is to prefer and chain EQ_REF tables (tables that uses an unique key to find a row) when searching for the best table combination. This significantly reduces row combinations that has to be examined. This is optimization is enabled when setting optimizer_prune_level=2 (which is now default). Implementation: - optimizer_prune_level has a new level, 2, which enables EQ_REF optimization in addition to the pruning done by level 1. Level 2 is now default. - Added JOIN::eq_ref_tables that contains bits of tables that could use potentially use EQ_REF access in the query. This is calculated in sort_and_filter_keyuse() Under optimizer_prune_level=2: - When the greedy_optimizer notices that the preceding table was an EQ_REF table, it tries to add an EQ_REF table next. If an EQ_REF table exists, only this one will be considered at this level. We also collect all EQ_REF tables chained by the next levels and these are ignored on the starting level as we have already examined these. If no EQ_REF table exists, we continue as normal. This optimization speeds up the greedy_optimizer combination test with ~25% Other things: - I ported the changes in MySQL 5.7 to greedy_optimizer.test to MariaDB to be able to ensure we can handle all cases that MySQL can do. - I have run all tests with --mysqld=--optimizer_prune_level=1 to verify that there where no test changes.
186 lines
7.2 KiB
Plaintext
186 lines
7.2 KiB
Plaintext
SET @start_global_value = @@global.optimizer_prune_level;
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SELECT @start_global_value;
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@start_global_value
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2
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SET @start_session_value = @@session.optimizer_prune_level;
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SELECT @start_session_value;
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@start_session_value
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2
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'#--------------------FN_DYNVARS_115_01-------------------------#'
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SET @@global.optimizer_prune_level = 0;
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SET @@global.optimizer_prune_level = DEFAULT;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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2
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SET @@session.optimizer_prune_level = 0;
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SET @@session.optimizer_prune_level = DEFAULT;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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2
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'#--------------------FN_DYNVARS_115_02-------------------------#'
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SET @@global.optimizer_prune_level = DEFAULT;
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SELECT @@global.optimizer_prune_level = 2;
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@@global.optimizer_prune_level = 2
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1
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SET @@session.optimizer_prune_level = DEFAULT;
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SELECT @@session.optimizer_prune_level = 2;
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@@session.optimizer_prune_level = 2
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1
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'#--------------------FN_DYNVARS_115_03-------------------------#'
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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2
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SET @@global.optimizer_prune_level = 0;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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0
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SET @@global.optimizer_prune_level = 1;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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1
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SET @@global.optimizer_prune_level = 2;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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2
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SET @@global.optimizer_prune_level = TRUE;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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1
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SET @@global.optimizer_prune_level = FALSE;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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0
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'#--------------------FN_DYNVARS_115_04-------------------------#'
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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2
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SET @@session.optimizer_prune_level = 0;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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0
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SET @@session.optimizer_prune_level = 1;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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1
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SET @@session.optimizer_prune_level = 2;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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2
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SET @@session.optimizer_prune_level = TRUE;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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1
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SET @@session.optimizer_prune_level = FALSE;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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0
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'#------------------FN_DYNVARS_115_05-----------------------#'
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SET @@global.optimizer_prune_level = ON;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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'Bug# 34840: Since it is not a boolean variable, it should give errors on 'ON' & 'OFF' values';
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SET @@global.optimizer_prune_level = OFF;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = 'ONN';
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = "OFFF";
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = TTRUE;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = FELSE;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = -1024;
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Warnings:
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Warning 1292 Truncated incorrect optimizer_prune_level value: '-1024'
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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0
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'Bug# 34840: Since it is not a boolean variable, it should no give errors on numeric values';
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SET @@global.optimizer_prune_level = 65536;
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Warnings:
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Warning 1292 Truncated incorrect optimizer_prune_level value: '65536'
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SET @@global.optimizer_prune_level = 3;
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Warnings:
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Warning 1292 Truncated incorrect optimizer_prune_level value: '3'
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select @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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2
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SET @@global.optimizer_prune_level = 65530.34;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@global.optimizer_prune_level = test;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = ON;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = OFF;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = ONN;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = ONF;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = ON;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = OF;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = 'OFN';
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = -2;
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Warnings:
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Warning 1292 Truncated incorrect optimizer_prune_level value: '-2'
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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0
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SET @@session.optimizer_prune_level = 65530.34;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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SET @@session.optimizer_prune_level = 65550;
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Warnings:
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Warning 1292 Truncated incorrect optimizer_prune_level value: '65550'
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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2
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SET @@session.optimizer_prune_level = test;
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ERROR 42000: Incorrect argument type to variable 'optimizer_prune_level'
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'#------------------FN_DYNVARS_115_06-----------------------#'
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SELECT @@global.optimizer_prune_level = VARIABLE_VALUE
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FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
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WHERE VARIABLE_NAME='optimizer_prune_level';
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@@global.optimizer_prune_level = VARIABLE_VALUE
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1
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'#------------------FN_DYNVARS_115_07-----------------------#'
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SELECT @@session.optimizer_prune_level = VARIABLE_VALUE
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FROM INFORMATION_SCHEMA.SESSION_VARIABLES
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WHERE VARIABLE_NAME='optimizer_prune_level';
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@@session.optimizer_prune_level = VARIABLE_VALUE
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1
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'#---------------------FN_DYNVARS_115_08----------------------#'
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SET @@optimizer_prune_level = 0;
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SET @@global.optimizer_prune_level = 1;
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SELECT @@optimizer_prune_level = @@global.optimizer_prune_level;
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@@optimizer_prune_level = @@global.optimizer_prune_level
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0
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'#---------------------FN_DYNVARS_115_09----------------------#'
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SET @@optimizer_prune_level = 1;
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SELECT @@optimizer_prune_level = @@local.optimizer_prune_level;
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@@optimizer_prune_level = @@local.optimizer_prune_level
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1
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SELECT @@local.optimizer_prune_level = @@session.optimizer_prune_level;
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@@local.optimizer_prune_level = @@session.optimizer_prune_level
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1
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'#---------------------FN_DYNVARS_115_10----------------------#'
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SET optimizer_prune_level = 1;
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SELECT @@optimizer_prune_level;
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@@optimizer_prune_level
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1
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SELECT local.optimizer_prune_level;
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ERROR 42S02: Unknown table 'local' in field list
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SELECT session.optimizer_prune_level;
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ERROR 42S02: Unknown table 'session' in field list
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SELECT optimizer_prune_level = @@session.optimizer_prune_level;
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ERROR 42S22: Unknown column 'optimizer_prune_level' in 'field list'
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SET @@global.optimizer_prune_level = @start_global_value;
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SELECT @@global.optimizer_prune_level;
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@@global.optimizer_prune_level
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2
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SET @@session.optimizer_prune_level = @start_session_value;
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SELECT @@session.optimizer_prune_level;
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@@session.optimizer_prune_level
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2
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