Re: Old WAL files under pg_xlog not getting delete - Mailing list pgsql-admin
| From | Keith |
|---|---|
| Subject | Re: Old WAL files under pg_xlog not getting delete |
| Date | |
| Msg-id | CAHw75vsvUPdJ0HQacm4agP25Jqy=KpWP5=CM9Fs6yV_qLnYq+g@mail.gmail.com Whole thread Raw |
| In response to | Re: Old WAL files under pg_xlog not getting delete (rammohan ganapavarapu <rammohanganap@gmail.com>) |
| List | pgsql-admin |
The archive_command is only for making secondary copies of the WAL files and doesn't control the files in the pg_xlogs folder itself (pg_wal in PG10+). Secondary uses could be backups or non-streaming replicas that just replay the WAL instead of connecting back to the primary.
What they were saying is that if you do have an archive_command set and it fails to run, postgresql will not remove the WAL files in pg_xlog until the archive_command successfully runs or is removed. It does this so that your backups or replicas don't lose WAL files in the time period that the archive_command is failing.
Keith
On Thu, Jan 31, 2019 at 1:52 PM rammohan ganapavarapu <rammohanganap@gmail.com> wrote:
Jay,If there is no max limit on how many files can be on FS at some point it will fill up disk space right? so you are saying if we dont have correct archive_command , postgres will do nothing? in my case i did not set archive_command. But from postgres documentation "The number of WAL segment files in pg_xlog directory depends on min_wal_size, max_wal_size and the amount of WAL generated in previous checkpoint cycles. When old log segment files are no longer needed, they are removed or recycled (that is, renamed to become future segments in the numbered sequence)." This statement is little confusing me with what you have said: "If that’s not correct, nothing will remove the WAL files.".Sorry if i am asking silly questions :(Thanks,RamOn Thu, Jan 31, 2019 at 8:37 AM John Scalia <jayknowsunix@gmail.com> wrote:Ram,Remember that keep_wal_segments is a minimum setting, not a maximum one. It’s telling the database to maintain at least that many segments. Plus, check how you’ve set the archive_command. If that’s not correct, nothing will remove the WAL files.—JaySent from my iPhoneRon,I have changed the wal_keep_segments=100 and restarted the postgresql processes but i still see 500+ files under pg_xlog, i had to run checkpoint manually to clean.RamOn Wed, Jan 30, 2019 at 7:19 PM Ron <ronljohnsonjr@gmail.com> wrote:On 1/30/19 9:09 PM, rammohan ganapavarapu wrote:Thank you all, but irrespective of count i have why is it keeping old files?
Because you're telling it to!!
max_wal_size= 1GB
wal_keep_segments=500and how is it using those files? Is there any processes that can flush or remove those files?
Change the parameter and restart the server...On Wed, Jan 30, 2019, 4:11 PM David G. Johnston <david.g.johnston@gmail.com wrote:On Wed, Jan 30, 2019 at 5:00 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> Hmm ... I would recommend to keep the xlog files in a subdir, not the
> root of the filesystem.
They are in a subdir (under /opt/pgdata), and the OP seems likely to
have omitted the self/parent hidden directories during his check as
well. Plus per the docs we actually expect 501 so there isn't a need
to account for 6 extra, just 5.
Dave--
Angular momentum makes the world go 'round.
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