Re: [PERFORM] Sudden crazy high CPU usage
On Wed, Apr 2, 2014 at 7:16 AM, Andres Freund and...@2ndquadrant.com wrote: On 2014-03-31 19:16:58 +0200, Niels Kristian Schjødt wrote: Yes, I could install perf, though I'm not familiar with it. What would i do? :-) As root: perf record -a sleep 5 perf report my-nice-perf-report.txt And then send the my-nice-perf-report.txt file. Locally it's much nicer to see the output using perf report without redirect into a file, you'll get an interactive UI. The Postgres wiki has a page dedicated to perf as well here: https://wiki.postgresql.org/wiki/Profiling_with_perf Regards, -- Michael -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
Sorry, but nothing unusual here either, I have compared the time just before with the same time the days before and the throughput pattern is exactly the same. No differences. Den 31/03/2014 kl. 22.01 skrev Will Platnick wplatn...@gmail.com: In New Relic, go back a half hour before the problem started so you can't see that this spike happened and send the same screenshot in. My guess is you have increased activity hitting the DB. Do you have pgbouncer or some kind of connection pooling sitting in front? 198 open server connections could account for an increase in load like you're seeing. Do you have postgresql addon in New Relic to show you how many queries are hitting the system to correlate data to? On Mon, Mar 31, 2014 at 1:36 PM, Sergey Konoplev gray...@gmail.com wrote: On Mon, Mar 31, 2014 at 3:25 AM, Niels Kristian Schjødt nielskrist...@autouncle.com wrote: I'm running postgresql 9.3 on a production server. An hour ago, out of the blue, I ran into an issue I have never encountered before: my server started to use CPU as crazy. The server is a standard ubuntu 12.04 LTE installation running only Postgres and Redis. The incident can be seen on the in numbers below: https://s3-eu-west-1.amazonaws.com/autouncle-public/other/cpu.png The increase doesn't look so sudden. My guess is that the server got some new activity. The advice is to setup the statistics collecting script by the link [1] and review the results for a period of hour or so. It shows charts of statements by CPU/IO/calls with aggregated stats, so you could probably find out more than with pure pg_stat_statements. [1] https://github.com/grayhemp/pgcookbook/blob/master/statement_statistics_collecting_and_reporting.md -- Kind regards, Sergey Konoplev PostgreSQL Consultant and DBA http://www.linkedin.com/in/grayhemp +1 (415) 867-9984, +7 (901) 903-0499, +7 (988) 888-1979 gray...@gmail.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
On 2014-03-31 19:16:58 +0200, Niels Kristian Schjødt wrote: Yes, I could install “perf”, though I’m not familiar with it. What would i do? :-) As root: perf record -a sleep 5 perf report my-nice-perf-report.txt And then send the my-nice-perf-report.txt file. Locally it's much nicer to see the output using perf report without redirect into a file, you'll get an interactive UI. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training Services -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
[PERFORM] Sudden crazy high CPU usage
I'm running postgresql 9.3 on a production server. An hour ago, out of the blue, I ran into an issue I have never encountered before: my server started to use CPU as crazy. The server is a standard ubuntu 12.04 LTE installation running only Postgres and Redis. The incident can be seen on the in numbers below: https://s3-eu-west-1.amazonaws.com/autouncle-public/other/cpu.png I imidiatly took a look at pg_stat_activity but nothing in there seemed suspicious. I also had a look at the postgres log, but nothing was in there too. I have pg_stat_statements running, so I reseted that one, and nothing really suspicious occurred in there, expect for the fact, that all queries were taking 100x times longer than usual. I have tried the following with no luck: • Restart clients connecting to the db • Restart postgres • Restart the whole server I have run memory tests on the server as well, and nothing seems to be wrong. No changes in any software running on the servers has been made within the last 24 hours. The question is: I have a streaming replication server running, which I have now done a failover to, and it runs fine. However I still have no clue why my master suddenly has become so CPU consuming, and how I can debug / trace it further down? -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
On Mon, Mar 31, 2014 at 5:25 AM, Niels Kristian Schjødt nielskrist...@autouncle.com wrote: I'm running postgresql 9.3 on a production server. An hour ago, out of the blue, I ran into an issue I have never encountered before: my server started to use CPU as crazy. The server is a standard ubuntu 12.04 LTE installation running only Postgres and Redis. The incident can be seen on the in numbers below: https://s3-eu-west-1.amazonaws.com/autouncle-public/other/cpu.png I imidiatly took a look at pg_stat_activity but nothing in there seemed suspicious. I also had a look at the postgres log, but nothing was in there too. I have pg_stat_statements running, so I reseted that one, and nothing really suspicious occurred in there, expect for the fact, that all queries were taking 100x times longer than usual. I have tried the following with no luck: * Restart clients connecting to the db * Restart postgres * Restart the whole server I have run memory tests on the server as well, and nothing seems to be wrong. No changes in any software running on the servers has been made within the last 24 hours. The question is: I have a streaming replication server running, which I have now done a failover to, and it runs fine. However I still have no clue why my master suddenly has become so CPU consuming, and how I can debug / trace it further down? Using linux 6? One possible culprit is Transparent Huge Page Compaction. It tends to hit severs with a lot of memory, especially if they've configured a lot of shared buffers. Google it a for a lot of info. There may be other issues masquerading as this one but it's the first thing to rule out. Symptoms are very high cpu utilization and poor performance that strikes without warning and then resolves also without warning (typically seconds or minutes after the event). For starters, take a look at the value of: /sys/kernel/mm/redhat_transparent_hugepage/enabled And do some due diligence research. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
Thanks, I don’t think overheating is an issue, it’s a large dell server, and I have checked the historic CPU temperature in the servers control panel, and no overheating has shown. Zone_reclaim_mode is already set to 0 Den 31/03/2014 kl. 16.50 skrev Scott Marlowe scott.marl...@gmail.com: On Mon, Mar 31, 2014 at 8:24 AM, Niels Kristian Schjødt nielskrist...@autouncle.com wrote: Thanks, this seems to persist after a reboot of the server though, and I have never in my server's 3 months life time experienced anything like it. Could it be overheating and therefore throttling the cores? Also another thing to look at on large memory machines with 1 CPU socket is zone_reclaim_mode being set to 1. Always set it to 0 on a linux machine running postgres. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
On Mon, Mar 31, 2014 at 3:25 AM, Niels Kristian Schjødt nielskrist...@autouncle.com wrote: I'm running postgresql 9.3 on a production server. An hour ago, out of the blue, I ran into an issue I have never encountered before: my server started to use CPU as crazy. The server is a standard ubuntu 12.04 LTE installation running only Postgres and Redis. The incident can be seen on the in numbers below: https://s3-eu-west-1.amazonaws.com/autouncle-public/other/cpu.png The increase doesn't look so sudden. My guess is that the server got some new activity. The advice is to setup the statistics collecting script by the link [1] and review the results for a period of hour or so. It shows charts of statements by CPU/IO/calls with aggregated stats, so you could probably find out more than with pure pg_stat_statements. [1] https://github.com/grayhemp/pgcookbook/blob/master/statement_statistics_collecting_and_reporting.md -- Kind regards, Sergey Konoplev PostgreSQL Consultant and DBA http://www.linkedin.com/in/grayhemp +1 (415) 867-9984, +7 (901) 903-0499, +7 (988) 888-1979 gray...@gmail.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] Sudden crazy high CPU usage
In New Relic, go back a half hour before the problem started so you can't see that this spike happened and send the same screenshot in. My guess is you have increased activity hitting the DB. Do you have pgbouncer or some kind of connection pooling sitting in front? 198 open server connections could account for an increase in load like you're seeing. Do you have postgresql addon in New Relic to show you how many queries are hitting the system to correlate data to? On Mon, Mar 31, 2014 at 1:36 PM, Sergey Konoplev gray...@gmail.com wrote: On Mon, Mar 31, 2014 at 3:25 AM, Niels Kristian Schjødt nielskrist...@autouncle.com wrote: I'm running postgresql 9.3 on a production server. An hour ago, out of the blue, I ran into an issue I have never encountered before: my server started to use CPU as crazy. The server is a standard ubuntu 12.04 LTE installation running only Postgres and Redis. The incident can be seen on the in numbers below: https://s3-eu-west-1.amazonaws.com/autouncle-public/other/cpu.png The increase doesn't look so sudden. My guess is that the server got some new activity. The advice is to setup the statistics collecting script by the link [1] and review the results for a period of hour or so. It shows charts of statements by CPU/IO/calls with aggregated stats, so you could probably find out more than with pure pg_stat_statements. [1] https://github.com/grayhemp/pgcookbook/blob/master/statement_statistics_collecting_and_reporting.md -- Kind regards, Sergey Konoplev PostgreSQL Consultant and DBA http://www.linkedin.com/in/grayhemp +1 (415) 867-9984, +7 (901) 903-0499, +7 (988) 888-1979 gray...@gmail.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
