Re: Time-Delayed Standbys

2013/12/9 KONDO Mitsumasa <kondo(dot)mitsumasa(at)lab(dot)ntt(dot)co(dot)jp>

> Hi Fabrízio,
>
> I test your v4 patch, and send your review comments.
>
> * Fix typo
> > 49 -# commited transactions from the master, specify a recovery time
> delay.
> > 49 +# committed transactions from the master, specify a recovery time
> delay.
>
> * Fix white space
> > 177 - if (secs <= 0 && microsecs <=0)
> > 177 + if (secs <= 0 && microsecs <=0 )
>
> * Add functionality (I propose)
> We can set negative number at min_standby_apply_delay. I think that this
> feature
> is for world wide replication situation. For example, master server is in
> Japan and slave server is in San Francisco. Japan time fowards than San
> Francisco time
> . And if we want to delay in this situation, it can need negative number
> in min_standby_apply_delay. So I propose that time delay conditional branch
> change under following.
> > - if (min_standby_apply_delay > 0)
> > + if (min_standby_apply_delay != 0)
> What do you think? It might also be working collectry.
>

what using interval instead absolute time?

Regards

Pavel

>
>
> * Problem 1
> I read your wittened document. There is "PITR has not affected".
> However, when I run PITR with min_standby_apply_delay=3000000, it cannot
> start server. The log is under following.
>
>> [mitsu-ko(at)localhost postgresql]$ bin/pg_ctl -D data2 start
>> server starting
>> [mitsu-ko(at)localhost postgresql]$ LOG: database system was interrupted;
>> last known up at 2013-12-08 18:57:00 JST
>> LOG: creating missing WAL directory "pg_xlog/archive_status"
>> cp: cannot stat `../arc/00000002.history':
>> LOG: starting archive recovery
>> LOG: restored log file "000000010000000000000041" from archive
>> LOG: redo starts at 0/41000028
>> LOG: consistent recovery state reached at 0/410000F0
>> LOG: database system is ready to accept read only connections
>> LOG: restored log file "000000010000000000000042" from archive
>> FATAL: cannot wait on a latch owned by another process
>> LOG: startup process (PID 30501) exited with exit code 1
>> LOG: terminating any other active server processes
>>
> We need recovery flag for controling PITR situation.
>
>
> That's all for now.
> If you are busy, please fix in your pace. I'm busy and I'd like to wait
> your time, too:-)
>
> Regards,
> --
> Mitsumasa KONDO
> NTT Open Source Software Center
>
>
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