Showing posts with label troubleshooting. Show all posts
Showing posts with label troubleshooting. Show all posts
Thursday, February 13, 2020
Useless Vacuuming
In previous blog posts that I've written about VACUUM, and I seem to be accumulating an uncomfortable number of those, I've talked about various things that can go wrong with vacuum, but one that I haven't really covered is when autovacuum seems to be running totally normally but you still have a VACUUM problem. In this blog post, I'd like to talk about how to recognize that situation, how to figure out what has caused it, how to avoid it via good monitoring, and how to recover if it happens.
Tuesday, May 13, 2014
Troubleshooting Database Corruption
When your database gets corrupted, one of the most important things to do is figure out why that happened, so that you can try to ensure that it doesn't happen again. After all, there's little point in going to a lot of trouble to restore a corrupt database from backup, or in attempting to repair the damage, if it's just going to get corrupted again. However, there are times when root cause analysis must take a back seat to getting your database back on line.
Tuesday, March 01, 2011
Troubleshooting Stuck VACUUMs
Over the years, I've occasionally encountered situations where VACUUM fails to make progress, and not fully understood why that was happening. Recently, I've come to a better understanding of how lock conflicts can result in VACUUM stalling out either at the beginning of the table, or part-way through. (If you're not already familiar with the types of locks that PostgreSQL uses, you may find it helpful to read through my earlier blog post on locking in PostgreSQL before reading on.)
Friday, December 03, 2010
Troubleshooting Database Unresponsiveness
From time to time, we get complaints on the pgsql-performance mailing list about a PostgreSQL database that - for the most part - performs reasonably well, but every once in a while it becomes unresponsive for some number of seconds or even minutes; and then eventually recovers. What's going on?
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