Patch: microseconds_in_slow_query_log

Slow query log contain output format like this:

# Time: 090402 9:23:36 # User@Host: XXX @ XXX [10.X.X.X]

This patch allow change format like this:

# Time: 090402 9:23:36.123456 # User@Host: XXX @ XXX [10.X.X.X]

This patch is included as part of slow_extended.

Switch between microseconds precision in slow query (slow_query_log_microseconds_timestamp=ON) log and typical seconds precision (slow_query_log_microseconds_timestamp=OFF).

https://blueprints.launchpad.net/percona-server/+spec/microseconds-in-query-log