This feature enhances the slow query log, allowing better granularity, filtering, and providing additional information. The mysqldumpslow script is also adapted accordingly.

Patch Origin

Percona, updates and fixes by Open Query.


  • log_slow_slave_statements – Log slow replicated statements to the slow log if it is open.
  • log_slow_filter – Log only the queries that followed certain execution plan. Multiple flags allowed in a comma-separated string: qc_miss, full_scan, full_join, tmp_table, tmp_table_on_disk, filesort, filesort_on_disk (default: no filter).
  • log_slow_rate_limit – Rate limit statement writes to slow log to only those from every (1/log_slow_rate_limit) session (default: 1).
  • log_slow_verbosity – Choose how verbose the messages to the slow log will be. Multiple flags allowed in a comma-separated string: microtime, query_plan, innodb (default: microtime).
    This can also be specified as
    minimal (microtime), standard (microtime,query_plan), or full (microtime,query_plan,innodb).
  • min_examined_row_limit – Don’t log queries which examine less than min_examined_row_limit rows to file (default: 0)
  • long_query_time – Modified existing option to (also) accept fractions of seconds (default: 10). Examples: 0.05 (50 milliseconds), 2.5 (2 1/2 seconds).

Note: prior to d7 patchset, the patch modifies long_query_time from seconds to microseconds (rather than fractional seconds); this broke backward compatibility for existing configurations. In d7 patchset, this has been corrected.

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