On 06/30/2015 07:52 AM, eudald_v wrote: > Two days from now, I've been experiencing that, randomly, the connections > rise up till they reach max connections, and the load average of the server > goes arround 300~400, making every command issued on the server take > forever. When this happens, ram is relatively low (70Gb used), cores > activity is lower than usual and sometimes swap happens (I've swappiness > configured to 10%) As Tom said, the most likely reason for this is application behavior and blocking locks. Try some of these queries on our scripts page: https://github.com/pgexperts/pgx_scripts/tree/master/locks However, I have seem some other things which cause these kinds of stalls: * runaway connection generation by the application, due to either a programming bug or an irresponsible web crawler (see https://www.pgexperts.com/blog/quinn_weaver/) * issues evicting blocks from shared_buffers: what is your shared_buffers set to? How large is your database? * Checkpoint stalls: what FS are you on? What are your transaction log settings for PostgreSQL? * Issues with the software/hardware stack around your storage, causing total IO stalls periodically. What does IO throughput look like before/during/after the stalls? The last was the cause the last time I dealt with a situation like yours; it turned out the issue was bad RAID card firmware where the card would lock up whenever the write-through buffer got too much pressure. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
