Re: Very slow update / hash join
От | Jeff Janes |
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Тема | Re: Very slow update / hash join |
Дата | |
Msg-id | CAMkU=1x=tz10a1KDW=LUQUKX+k6LFU8Nn4JhrCB7g+tkasOtNw@mail.gmail.com обсуждение исходный текст |
Ответ на | Very slow update / hash join (Kurt Roeckx <kurt@roeckx.be>) |
Ответы |
Re: Very slow update / hash join
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Список | pgsql-general |
On Wed, May 4, 2016 at 3:22 PM, Kurt Roeckx <kurt@roeckx.be> wrote: > Hi, > > I have an update query that's been running for 48 hours now. > Since it started it used about 2.5% CPU, and is writing to the > disk at about 3 MB/s, and reading at about 2 MB/s. It's mostly > waiting for the disks. The easiest way to figure out what is going on is to identify the process, and then trace it with something like: strace -T -ttt -y -p <PID of process> That should make it obvious which file it is waiting for IO on. Then you can look up that relfilenode in pg_class to see what table/index it is. > The table itself is 53GB, and the table it updates from is only > 3.3 GB. There are some index on some of the fields (like the id), > but none of them are being updated. I tried removing those that > did get updated but that had little effect. It does have foreign > keys to other tables, and other tables references it, but none of > the keys should get updated. What version of PostgreSQL are you using? Have you tried dropping the foreign keys? Cheers, Jeff
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