General query log performance


I’m wondering how big impact on performance would have turning on the general query log. I read in manual it should be turned off in production environment to increase the performance but I didn’t find any information about performance gain (how much cpu/disk usage it would take). Is it like 1% performance lost or could it be bigger? Basically I just want to turn it on for a week to analyze later that query log.

Thanks in advance

Enabling general log may have different effect on server performance depending on your query complexity - if you run 10000 simple queries/sec log overhead will be much larger than if you run 5 complicated queries/sec

Generally I would not expect it to cause more than few percent overhead. I guess should be some 1% for queries of medium complexity up to 10% for very simple queries.

My main concern with full query logging is it is eating up space so quickly )

Cool, thanks again for your help! I hope that query log won’t eat my disk space in one week )