Обсуждение: Warm standby can't start because logs stream too quickly from the master

Looking at the startup process: postgres 16749 4.1 6.7 17855104 8914544 ? Ss 18:36 0:44 postgres: startup process recovering 0000000800005B1C00000030 Then a few seconds later: postgres 16749 4.2 7.0 17855104 9294172 ? Ss 18:36 0:47 postgres: startup process recovering 0000000800005B1C00000047 It's replaying logs from the master, but it's always a few behind, so startup never finishes. Here's a demonstration: # while :; do echo $(ls data/pg_xlog/ | grep -n $(ps aux | egrep "startup process" | awk '{print $15}')) $(ls data/pg_xlog/ | wc -l); sleep 1; done # current replay location # number of WALs in pg_xlog 1655:0000000800005B1C00000064 1659 1656:0000000800005B1C00000065 1660 1658:0000000800005B1C00000067 1661 1659:0000000800005B1C00000068 1662 1660:0000000800005B1C00000069 1663 Generally this works itself out if I wait (sometimes a really long time). Is there a configuration option that allows a warm standby to start without having fully replayed the logs from the master? * Note: wal_keep_segments is set to 8192 on these servers, which have large disks, to allow for recovery within a couple of hours of a failover without resorting to restoring from archive * This is specifically an issue for pgpool recovery, which fails if a standby can't start within (by default) 300 seconds. Open to toggling that param if there's no way around this.

On 12/02/2017 11:02 AM, Zach Walton wrote:
>
> Generally this works itself out if I wait (sometimes a really long 
> time). Is there a configuration option that allows a warm standby to 
> start without having fully replayed the logs from the master?
>
> * Note: wal_keep_segments is set to 8192 on these servers, which have 
> large disks, to allow for recovery within a couple of hours of a 
> failover without resorting to restoring from archive
> * This is specifically an issue for pgpool recovery, which fails if a 
> standby can't start within (by default) 300 seconds. Open to toggling 
> that param if there's no way around this.

It needs to only reach a consistent state, it doesn't need restore all 
logs. What does your recovery.conf say and are you *100% sure% you 
issued a pg_stop_backup()?

JD



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On Sat, Dec 2, 2017 at 11:02 AM, Zach Walton wrote: > Looking at the startup process: > > postgres 16749 4.1 6.7 17855104 8914544 ? Ss 18:36 0:44 postgres: > startup process recovering 0000000800005B1C00000030 > > Then a few seconds later: > > postgres 16749 4.2 7.0 17855104 9294172 ? Ss 18:36 0:47 postgres: > startup process recovering 0000000800005B1C00000047 > > It's replaying logs from the master, but it's always a few behind, so > startup never finishes. Here's a demonstration: > > # while :; do echo $(ls data/pg_xlog/ | grep -n $(ps aux | egrep "startup > process" | awk '{print $15}')) $(ls data/pg_xlog/ | wc -l); sleep 1; done > # current replay location # number of WALs in pg_xlog > 1655:0000000800005B1C00000064 1659 > 1656:0000000800005B1C00000065 1660 > 1658:0000000800005B1C00000067 1661 > 1659:0000000800005B1C00000068 1662 > 1660:0000000800005B1C00000069 1663 > > Generally this works itself out if I wait (sometimes a really long time). > Is there a configuration option that allows a warm standby to start without > having fully replayed the logs from the master? > Warm standbys aren't supposed to start up, that is what makes them warm. Are you trying to set up a hot standby? Are you trying to promote a warm standby to be the new master (but usually you would do that when the current master has died, and so would no longer be generating log.) Cheers, Jeff

This was my fault. I'd restored recovery.conf from recovery.done to try to recover manually after automated recovery failed. Everything's working after stopping the database and running pgpool online recovery again. Thanks for the help. On Sat, Dec 2, 2017 at 1:55 PM, Joshua D. Drake wrote: > On 12/02/2017 11:02 AM, Zach Walton wrote: > >> >> Generally this works itself out if I wait (sometimes a really long time). >> Is there a configuration option that allows a warm standby to start without >> having fully replayed the logs from the master? >> >> * Note: wal_keep_segments is set to 8192 on these servers, which have >> large disks, to allow for recovery within a couple of hours of a failover >> without resorting to restoring from archive >> * This is specifically an issue for pgpool recovery, which fails if a >> standby can't start within (by default) 300 seconds. Open to toggling that >> param if there's no way around this. >> > > It needs to only reach a consistent state, it doesn't need restore all > logs. What does your recovery.conf say and are you *100% sure% you issued a > pg_stop_backup()? > > JD > > > > -- > Command Prompt, Inc. || http://the.postgres.company/ || @cmdpromptinc > > PostgreSQL Centered full stack support, consulting and development. > Advocate: @amplifypostgres || Learn: https://pgconf.org > ***** Unless otherwise stated, opinions are my own. ***** > >