Ow Mun Heng <Ow.Mun.Heng at wdc.com> writes:
> I'm not sure what is happening, usually when the slave lags behind, I
> will stop the slon process and then add in the -o10 -g500 options to the
> master process an I usually will see that the syncs on the subscriber
> will be grouped together.
>
> AS of right now, I'm not seeing this happening and it's just processing
> the syncs 1 by 1 and it's taking a long time for this to happen.
>
> I also tried the -o10 -g500 on both the master and the slave and still
> it goes 1 by 1.
> 2008-02-22 01:58:51 MYT DEBUG2 remoteHelperThread_1_1: inserts=0 updates=0 deletes=0
> 2008-02-22 01:58:51 MYT DEBUG2 remoteWorkerThread_1: SYNC 483711 done in 88.818 seconds
> 2008-02-22 02:00:07 MYT DEBUG2 remoteHelperThread_1_1: inserts=1984 updates=0 deletes=0
> 2008-02-22 02:00:10 MYT DEBUG2 remoteWorkerThread_1: SYNC 483712 done in 78.634 seconds
> 2008-02-22 02:01:34 MYT DEBUG2 remoteHelperThread_1_1: inserts=529 updates=0 deletes=56
> 2008-02-22 02:01:36 MYT DEBUG2 remoteWorkerThread_1: SYNC 483713 done in 85.745 seconds
> 2008-02-22 02:03:25 MYT DEBUG2 remoteHelperThread_1_1: inserts=1532 updates=0 deletes=0
> 2008-02-22 02:03:28 MYT DEBUG2 remoteWorkerThread_1: SYNC 483714 done in 112.476 seconds
> 2008-02-22 02:05:47 MYT DEBUG2 remoteHelperThread_1_1: inserts=1557 updates=0 deletes=0
> 2008-02-22 02:05:49 MYT DEBUG2 remoteWorkerThread_1: SYNC 483715 done in 140.691 seconds
> 2008-02-22 02:08:26 MYT DEBUG2 remoteHelperThread_1_1: inserts=2600 updates=0 deletes=225
> 2008-02-22 02:08:27 MYT DEBUG2 remoteWorkerThread_1: SYNC 483716 done in 157.839 seconds

I believe that -o10 causes Slony-I to try to track having SYNC
processing time take an estimated time of 10ms per group; the value is
measured in milliseconds, not seconds.

That being the case, if the last *single* SYNC took "lots more than
10ms," then the slon will not be considering processing several SYNCs
at once.  (And note that since the times were also >>> 10s, the
principle would still hold if -o was measuring in seconds.)

Based on the timings you indicate, the only way that you'll see SYNC
grouping is if you set the value to something more like 200000.
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