mirror of
https://github.com/MariaDB/server.git
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ef4c0f68d1
use limit efficiently Bug #36569: UPDATE ... WHERE ... ORDER BY... always does a filesort even if not required Also two bugs reported after QA review (before the commit of bugs above to public trees, no documentation needed): Bug #53737: Performance regressions after applying patch for bug 36569 Bug #53742: UPDATEs have no effect after applying patch for bug 36569 Execution of single-table UPDATE and DELETE statements did not use the same optimizer as was used in the compilation of SELECT statements. Instead, it had an optimizer of its own that did not take into account that you can omit sorting by retrieving rows using an index. Extra optimization has been added: when applicable, single-table UPDATE/DELETE statements use an existing index instead of filesort. A corresponding SELECT query would do the former. Also handling of the DESC ordering expression has been added when reverse index scan is applicable. From now on most single table UPDATE and DELETE statements show the same disk access patterns as the corresponding SELECT query. We verify this by comparing the result of SHOW STATUS LIKE 'Sort% Currently the get_index_for_order function a) checks quick select index (if any) for compatibility with the ORDER expression list or b) chooses the cheapest available compatible index, but only if the index scan is cheaper than filesort. Second way is implemented by the new test_if_cheaper_ordering function (extracted part the test_if_skip_sort_order()). mysql-test/r/log_state.result: Updated result for optimized query, bug #36569. mysql-test/r/single_delete_update.result: Test case for bug #30584, bug #36569 and bug #53742. mysql-test/r/update.result: Updated result for optimized query, bug #30584. Note: "Handler_read_last 1" omitted, see bug 52312: lost Handler_read_last status variable. mysql-test/t/single_delete_update.test: Test case for bug #30584, bug #36569 and bug #53742. sql/opt_range.cc: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required * get_index_for_order() has been rewritten entirely and moved to sql_select.cc New QUICK_RANGE_SELECT::make_reverse method has been added. sql/opt_range.h: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required * get_index_for_order() has been rewritten entirely and moved to sql_select.cc New functions: * QUICK_SELECT_I::make_reverse() * SQL_SELECT::set_quick() sql/records.cc: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required * init_read_record_idx() has been modified to allow reverse index scan New functions: * rr_index_last() * rr_index_desc() sql/records.h: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required init_read_record_idx() has been modified to allow reverse index scan sql/sql_delete.cc: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required mysql_delete: an optimization has been added to skip unnecessary sorting with ORDER BY clause where select result ordering is acceptable. sql/sql_select.cc: Bug #30584, bug #36569, bug #53737, bug #53742: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required The const_expression_in_where function has been modified to accept both Item and Field pointers. New functions: * get_index_for_order() * test_if_cheaper_ordering() has been extracted from test_if_skip_sort_order() to share with get_index_for_order() * simple_remove_const() sql/sql_select.h: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required New functions: * test_if_cheaper_ordering() * simple_remove_const() * get_index_for_order() sql/sql_update.cc: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required mysql_update: an optimization has been added to skip unnecessary sorting with ORDER BY clause where a select result ordering is acceptable. sql/table.cc: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required New functions: * TABLE::update_const_key_parts() * is_simple_order() sql/table.h: Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort even if not required New functions: * TABLE::update_const_key_parts() * is_simple_order()
373 lines
13 KiB
Text
373 lines
13 KiB
Text
SET @old_general_log= @@global.general_log;
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SET @old_general_log_file= @@global.general_log_file;
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SET @old_slow_query_log= @@global.slow_query_log;
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SET @old_slow_query_log_file= @@global.slow_query_log_file;
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set global general_log= OFF;
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truncate table mysql.general_log;
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truncate table mysql.slow_log;
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show global variables
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where Variable_name = 'log' or Variable_name = 'log_slow_queries' or
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Variable_name = 'general_log' or Variable_name = 'slow_query_log';
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Variable_name Value
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general_log OFF
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log OFF
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log_slow_queries OFF
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slow_query_log OFF
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flush logs;
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set global general_log= ON;
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create table t1(f1 int);
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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TIMESTAMP USER_HOST # 1 Query create table t1(f1 int)
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TIMESTAMP USER_HOST # 1 Query select * from mysql.general_log
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set global general_log= OFF;
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drop table t1;
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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TIMESTAMP USER_HOST # 1 Query create table t1(f1 int)
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TIMESTAMP USER_HOST # 1 Query select * from mysql.general_log
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TIMESTAMP USER_HOST # 1 Query set global general_log= OFF
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set global general_log= ON;
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flush logs;
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show global variables
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where Variable_name = 'log' or Variable_name = 'log_slow_queries' or
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Variable_name = 'general_log' or Variable_name = 'slow_query_log';
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Variable_name Value
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general_log ON
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log ON
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log_slow_queries OFF
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slow_query_log OFF
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# Establish connection con1 (user=root)
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# Switch to connection con1
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set @long_query_time = <long_query_time>;
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set session long_query_time = @long_query_time;
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select sleep(@long_query_time + 1);
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sleep(@long_query_time + 1)
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0
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select * from mysql.slow_log where sql_text NOT LIKE '%slow_log%';
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start_time user_host query_time lock_time rows_sent rows_examined db last_insert_id insert_id server_id sql_text
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# Switch to connection default
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set global slow_query_log= ON;
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# Switch to connection con1
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set session long_query_time = @long_query_time;
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select sleep(@long_query_time + 1);
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sleep(@long_query_time + 1)
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0
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select * from mysql.slow_log where sql_text NOT LIKE '%slow_log%';
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start_time user_host query_time lock_time rows_sent rows_examined db last_insert_id insert_id server_id sql_text
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TIMESTAMP USER_HOST QUERY_TIME 00:00:00 1 0 test 0 0 1 select sleep(@long_query_time + 1)
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# Switch to connection default
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show global variables
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where Variable_name = 'log' or Variable_name = 'log_slow_queries' or
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Variable_name = 'general_log' or Variable_name = 'slow_query_log';
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Variable_name Value
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general_log ON
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log ON
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log_slow_queries ON
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slow_query_log ON
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set global general_log= ON;
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set global general_log= OFF;
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set global general_log= OFF;
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set global slow_query_log= ON;
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set global slow_query_log= OFF;
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set global slow_query_log= OFF;
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set global general_log= ON;
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truncate table mysql.general_log;
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create table t1(f1 int);
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drop table t1;
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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TIMESTAMP USER_HOST # 1 Query create table t1(f1 int)
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TIMESTAMP USER_HOST # 1 Query drop table t1
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TIMESTAMP USER_HOST # 1 Query select * from mysql.general_log
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set global general_log= OFF;
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truncate table mysql.general_log;
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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set global general_log= ON;
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show global variables
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where Variable_name = 'log' or Variable_name = 'log_slow_queries' or
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Variable_name = 'general_log' or Variable_name = 'slow_query_log';
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Variable_name Value
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general_log ON
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log ON
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log_slow_queries OFF
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slow_query_log OFF
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show variables like 'general_log_file';
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Variable_name Value
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general_log_file #
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show variables like 'slow_query_log_file';
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Variable_name Value
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slow_query_log_file #
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show variables like 'log_output';
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Variable_name Value
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log_output FILE,TABLE
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set global general_log_file='/not existing path/log.master';
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ERROR 42000: Variable 'general_log_file' can't be set to the value of '/not existing path/log.master'
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set global general_log_file='MYSQLTEST_VARDIR';
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ERROR 42000: Variable 'general_log_file' can't be set to the value of 'MYSQLTEST_VARDIR'
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set global general_log_file='';
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ERROR 42000: Variable 'general_log_file' can't be set to the value of ''
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show variables like 'general_log_file';
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Variable_name Value
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general_log_file #
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set global general_log= OFF;
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set global general_log_file='MYSQLTEST_VARDIR/tmp/log.master';
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set global general_log= ON;
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create table t1(f1 int);
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drop table t1;
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set global general_log= OFF;
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set global general_log_file=default;
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set global general_log= ON;
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create table t1(f1 int);
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drop table t1;
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show variables like 'general_log_file';
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Variable_name Value
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general_log_file #
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show variables like 'slow_query_log_file';
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Variable_name Value
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slow_query_log_file #
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set global general_log= default;
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set global slow_query_log= default;
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set global general_log_file= default;
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set global slow_query_log_file= default;
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show variables like 'general_log';
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Variable_name Value
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general_log OFF
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show variables like 'slow_query_log';
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Variable_name Value
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slow_query_log OFF
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set global general_log=ON;
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set global log_output=default;
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show variables like 'log_output';
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Variable_name Value
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log_output FILE
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set global general_log=OFF;
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set global log_output=FILE;
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truncate table mysql.general_log;
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show variables like 'log_output';
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Variable_name Value
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log_output FILE
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set global general_log=ON;
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create table t1(f1 int);
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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set global general_log=OFF;
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set global log_output="FILE,TABLE";
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show variables like 'log_output';
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Variable_name Value
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log_output FILE,TABLE
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set global general_log=ON;
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drop table t1;
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select * from mysql.general_log;
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event_time user_host thread_id server_id command_type argument
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TIMESTAMP USER_HOST # 1 Query drop table t1
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TIMESTAMP USER_HOST # 1 Query select * from mysql.general_log
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SET @@global.general_log = @old_general_log;
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SET @@global.general_log_file = @old_general_log_file;
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SET @@global.slow_query_log = @old_slow_query_log;
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SET @@global.slow_query_log_file = @old_slow_query_log_file;
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SET GLOBAL general_log = ON;
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SET GLOBAL slow_query_log = ON;
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FLUSH TABLES WITH READ LOCK;
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SET GLOBAL general_log = OFF;
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SET GLOBAL slow_query_log = OFF;
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UNLOCK TABLES;
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FLUSH TABLES WITH READ LOCK;
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SET GLOBAL general_log = ON;
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SET GLOBAL slow_query_log = ON;
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UNLOCK TABLES;
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SET GLOBAL READ_ONLY = ON;
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SET GLOBAL general_log = OFF;
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SET GLOBAL slow_query_log = OFF;
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SET GLOBAL READ_ONLY = OFF;
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SET GLOBAL READ_ONLY = ON;
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SET GLOBAL general_log = ON;
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SET GLOBAL slow_query_log = ON;
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SET GLOBAL READ_ONLY = OFF;
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SET GLOBAL general_log = @old_general_log;
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SET GLOBAL slow_query_log = @old_slow_query_log;
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SET GLOBAL general_log = ON;
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SHOW VARIABLES LIKE 'general_log';
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Variable_name Value
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general_log ON
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SHOW VARIABLES LIKE 'log';
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Variable_name Value
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log ON
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SELECT @@general_log, @@log;
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@@general_log @@log
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1 1
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SET GLOBAL log = 0;
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Warnings:
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Warning 1287 The syntax '@@log' is deprecated and will be removed in MySQL 7.0. Please use '@@general_log' instead
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SHOW VARIABLES LIKE 'general_log';
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Variable_name Value
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general_log OFF
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SHOW VARIABLES LIKE 'log';
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Variable_name Value
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log OFF
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SELECT @@general_log, @@log;
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@@general_log @@log
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0 0
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SET GLOBAL general_log = 1;
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SHOW VARIABLES LIKE 'general_log';
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Variable_name Value
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general_log ON
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SHOW VARIABLES LIKE 'log';
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Variable_name Value
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log ON
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SELECT @@general_log, @@log;
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@@general_log @@log
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1 1
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SHOW VARIABLES LIKE 'slow_query_log';
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Variable_name Value
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slow_query_log OFF
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SHOW VARIABLES LIKE 'log_slow_queries';
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Variable_name Value
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log_slow_queries OFF
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SELECT @@slow_query_log, @@log_slow_queries;
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@@slow_query_log @@log_slow_queries
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0 0
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SET GLOBAL log_slow_queries = 0;
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Warnings:
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Warning 1287 The syntax '@@log_slow_queries' is deprecated and will be removed in MySQL 7.0. Please use '@@slow_query_log' instead
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SHOW VARIABLES LIKE 'slow_query_log';
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Variable_name Value
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slow_query_log OFF
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SHOW VARIABLES LIKE 'log_slow_queries';
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Variable_name Value
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log_slow_queries OFF
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SELECT @@slow_query_log, @@log_slow_queries;
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@@slow_query_log @@log_slow_queries
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0 0
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SET GLOBAL slow_query_log = 1;
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SHOW VARIABLES LIKE 'slow_query_log';
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Variable_name Value
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slow_query_log ON
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SHOW VARIABLES LIKE 'log_slow_queries';
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Variable_name Value
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log_slow_queries ON
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SELECT @@slow_query_log, @@log_slow_queries;
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@@slow_query_log @@log_slow_queries
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1 1
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SET GLOBAL general_log = @old_general_log;
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SET GLOBAL slow_query_log = @old_slow_query_log;
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SET GLOBAL general_log_file= CONCAT('/not existing path/log.maste', 'r');
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ERROR 42000: Variable 'general_log_file' can't be set to the value of '/not existing path/log.master'
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SET GLOBAL general_log_file= NULL;
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ERROR 42000: Variable 'general_log_file' can't be set to the value of 'NULL'
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SET GLOBAL slow_query_log_file= CONCAT('/not existing path/log.maste', 'r');
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ERROR 42000: Variable 'slow_query_log_file' can't be set to the value of '/not existing path/log.master'
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SET GLOBAL slow_query_log_file= NULL;
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ERROR 42000: Variable 'slow_query_log_file' can't be set to the value of 'NULL'
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SET GLOBAL general_log_file= @old_general_log_file;
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SET GLOBAL slow_query_log_file= @old_slow_query_log_file;
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# --
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# -- Bug#32748: Inconsistent handling of assignments to
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# -- general_log_file/slow_query_log_file.
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# --
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SET GLOBAL general_log_file = 'bug32748.query.log';
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SET GLOBAL slow_query_log_file = 'bug32748.slow.log';
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SHOW VARIABLES LIKE '%log_file';
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Variable_name Value
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general_log_file bug32748.query.log
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slow_query_log_file bug32748.slow.log
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SET GLOBAL general_log_file = @old_general_log_file;
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SET GLOBAL slow_query_log_file = @old_slow_query_log_file;
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# -- End of Bug#32748.
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deprecated:
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SET GLOBAL log = 0;
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Warnings:
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Warning 1287 The syntax '@@log' is deprecated and will be removed in MySQL 7.0. Please use '@@general_log' instead
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SET GLOBAL log_slow_queries = 0;
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Warnings:
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Warning 1287 The syntax '@@log_slow_queries' is deprecated and will be removed in MySQL 7.0. Please use '@@slow_query_log' instead
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SET GLOBAL log = DEFAULT;
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Warnings:
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Warning 1287 The syntax '@@log' is deprecated and will be removed in MySQL 7.0. Please use '@@general_log' instead
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SET GLOBAL log_slow_queries = DEFAULT;
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Warnings:
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Warning 1287 The syntax '@@log_slow_queries' is deprecated and will be removed in MySQL 7.0. Please use '@@slow_query_log' instead
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not deprecated:
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SELECT @@global.general_log_file INTO @my_glf;
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SELECT @@global.slow_query_log_file INTO @my_sqlf;
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SET GLOBAL general_log = 0;
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SET GLOBAL slow_query_log = 0;
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SET GLOBAL general_log_file = 'WL4403_G.log';
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SET GLOBAL slow_query_log_file = 'WL4403_SQ.log';
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SET GLOBAL general_log_file = @my_glf;
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SET GLOBAL slow_query_log_file = @my_sqlf;
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SET GLOBAL general_log = DEFAULT;
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SET GLOBAL slow_query_log = DEFAULT;
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SET @@global.general_log = @old_general_log;
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SET @@global.general_log_file = @old_general_log_file;
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SET @@global.slow_query_log = @old_slow_query_log;
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SET @@global.slow_query_log_file = @old_slow_query_log_file;
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#
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# Bug #49756 Rows_examined is always 0 in the slow query log
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# for update statements
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#
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SET @old_log_output = @@global.log_output;
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SET GLOBAL log_output = "TABLE";
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SET GLOBAL slow_query_log = ON;
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SET GLOBAL long_query_time = 0.001;
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TRUNCATE TABLE mysql.slow_log;
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (b INT, PRIMARY KEY (b));
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INSERT INTO t2 VALUES (3),(4);
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INSERT INTO t1 VALUES (1+sleep(.01)),(2);
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INSERT INTO t1 SELECT b+sleep(.01) from t2;
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UPDATE t1 SET a=a+sleep(.01) WHERE a>2;
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UPDATE t1 SET a=a+sleep(.01) ORDER BY a DESC;
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UPDATE t2 set b=b+sleep(.01) limit 1;
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UPDATE t1 SET a=a+sleep(.01) WHERE a in (SELECT b from t2);
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DELETE FROM t1 WHERE a=a+sleep(.01) ORDER BY a LIMIT 2;
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SELECT rows_examined,sql_text FROM mysql.slow_log;
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rows_examined sql_text
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0 INSERT INTO t1 VALUES (1+sleep(.01)),(2)
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2 INSERT INTO t1 SELECT b+sleep(.01) from t2
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4 UPDATE t1 SET a=a+sleep(.01) WHERE a>2
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8 UPDATE t1 SET a=a+sleep(.01) ORDER BY a DESC
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1 UPDATE t2 set b=b+sleep(.01) limit 1
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4 UPDATE t1 SET a=a+sleep(.01) WHERE a in (SELECT b from t2)
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6 DELETE FROM t1 WHERE a=a+sleep(.01) ORDER BY a LIMIT 2
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DROP TABLE t1,t2;
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TRUNCATE TABLE mysql.slow_log;
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# end of bug#49756
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End of 5.1 tests
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# --
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# -- Bug#38124: "general_log_file" variable silently unset when
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# -- using expression
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# --
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SET GLOBAL general_log_file = DEFAULT;
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SELECT @@general_log_file INTO @my_glf;
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SET GLOBAL general_log_file = 'BUG38124.LOG';
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SELECT @@general_log_file;
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@@general_log_file
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BUG38124.LOG
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SET GLOBAL general_log_file = concat('BUG38124-2.LOG');
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SELECT @@general_log_file;
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@@general_log_file
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BUG38124-2.LOG
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SET GLOBAL general_log_file = substr('BUG38124-2.LOG',3,6);
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SELECT @@general_log_file;
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@@general_log_file
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G38124
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SET GLOBAL general_log_file = DEFAULT;
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SELECT @@general_log_file = @my_glf;
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@@general_log_file = @my_glf
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1
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SET GLOBAL general_log_file = @old_general_log_file;
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# Close connection con1
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SET GLOBAL long_query_time = DEFAULT;
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SET GLOBAL log_output = @old_log_output;
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SET global general_log = @old_general_log;
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SET global general_log_file = @old_general_log_file;
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SET global slow_query_log = @old_slow_query_log;
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SET global slow_query_log_file = @old_slow_query_log_file;
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