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How do I enable slow query logging?
To enable the slow query log, type the following command at the mysql> prompt: SET GLOBAL slow_query_log = ‘ON’; There are additional options that you can set for the slow query log: By default, when the slow query log is enabled, it logs any query that takes longer than 10 seconds to run.
Where is the MySQL slow query log?
/var/lib/mysql
By default, the slow query log file is located at /var/lib/mysql/hostname-slow. log.
Why are my SQL queries so slow?
Poor Database Performance The system is too slow. Tasks are taking too long. Applications running slowly or timing out. Some queries taking forever.
How to select general query log and slow query log?
To write general and slow query log entries only to the log tables, use –log_output=TABLE to select tables as the log destination and –general_log and –slow_query_log to enable both logs.
What are the rules for a slow query in MySQL?
The query must have taken at least long_query_time seconds, or log_queries_not_using_indexes must be enabled and the query used no indexes for row lookups. The query must have examined at least min_examined_row_limit rows. The query must not be suppressed according to the log_throttle_queries_not_using_indexes setting.
Is the TRUNCATE TABLE valid in slow query log?
The example uses the general query log; the procedure for the slow query log is similar but uses the slow_log table and slow_query_log system variable. TRUNCATE TABLE is a valid operation on a log table. It can be used to expire log entries. RENAME TABLE is a valid operation on a log table.
What are the administrative statements in slow query?
Administrative statements include ALTER TABLE , ANALYZE TABLE , CHECK TABLE , CREATE INDEX , DROP INDEX , OPTIMIZE TABLE, and REPAIR TABLE . To include queries that do not use indexes for row lookups in the statements written to the slow query log, enable the log_queries_not_using_indexes system variable.