… additional information. The other is slow log enabled by –log-slow-queries parameter (MySQL 5.1 requires also –slow-query-log), which was designed to store poorly performing queries that run at least 2 seconds. Percona actually extended the slow log to…
Post: Impact of logging on MySQL’s performance
February 10, 2009 By 8 Comments
… how much logging impacts on performance. When we do performance audit often we log every query to find not only slow queries. A… 20-25k queries per second. If all queries are logged – a slow log is populated at rate about 10MB/sec. This is… are two conclusions can be made: It is safe to log slow queries with execution time bigger than a second without worry…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
…_limit AND log_slow_filter. log-slow-queries[=name] Log slow queries to this log file. Defaults logging to hostname-slow.log file. Must be enabled to activate other slow log options… SESSION and SET GLOBAL. log_slow_rate_limit=# Rate limit statement writes to slow log to only those from every (1/log_slow_rate_limit) session…
Post: A (prototype) lower impact slow query log
September 20, 2012 By 12 Comments
… re-examine how we could provide slow query log type functionality to our users. The slow query log code inside the MySQL server does… for our case of writing the slow query log, if we had a buffer that was the log entry, we could just call… (no slow query log): 13 seconds MySQL with slow query log enabled: 18 seconds My audit plugin slow query log: 15 seconds straight Drizzle (no slow query log…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… slow /path/to/slow.log By default, this outputs the top 10 most expensive queries, in total execution time. By the way, the slow query logs… sniffing, or other techniques to get more information than the slow log gives us; but by far the richest and most efficient…
Post: Does Slow query log logs all slow queries ?
June 25, 2007 By 3 Comments
… Slow query log to log all slow queries to catch problematic queries or for audit purposes. In fact however not all the queries are logged. I already mentioned mysql slave queries are not logged to slow query log and it looks like I… thread is replication thread causes queries to be omitted from slow query log but the fact thread uses SET TIMESTAMP functionality. If…
Comment: Get Me Some Query Logs!
November 23, 2012 By 14 Comments
… below, any clues appreciated 
./full-slow-log -v Discovering slow_query_log=1 Discovering slow_query_log_file=/var/log/mysqld_slow.log Discovering long_query_time=1.000000… set to the value of ‘/var/log/mysqld_slow.log-full-20121123202725′ Error occurred while trying: Setting slow_query_log_file=/var/log/mysqld_slow.log-full-20121123202725
Post: Microslow patch for 5.1.20
July 18, 2007 By 3 Comments
… course enable slow logging with –slow-query-log parameter. MySQL 5.1 has this nice feature which allows you to redirect query log (it’s actually called general log now) and slow log to CSV tables mysql.general_log and mysql.slow_log respectively. The patch… for your logs to the plain old-fashioned files. In MySQL 5.1 it’s done by setting –log-slow-queries=slow.log and –log-output…
Post: Replaying database load with Percona Playback
October 25, 2012 By 9 Comments
… another different server. It can replay queries from tcpdump or slow query logs. With this tool you can measure how a database… information: SET GLOBAL slow_query_log=1; SET GLOBAL long_query_time=0; With long_query_time we are logging all queries that….1 –mysql-user=root –mysql-schema=my_db –query-log-file=slow.log Executed 429467 queries Spent 00:00:59.668649 executing queries…
Comment: Get Me Some Query Logs!
December 19, 2012 By 14 Comments
… duration. If I recall correctly, RDS does allow you to log slow queries to a table. This has a lot of I… logs from the mysql.slow_query log, but you can export the data into a format that’s compatible with file-based slow query log… full-slow-log script. The script to export the slow-query log table is called “export-slow-log-table”. Another drawback of the table-based slow query log…
