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From Knut Anders Hatlen <Knut.Hat...@Sun.COM>
Subject Re: Derby replication failed under heavy load
Date Fri, 24 Jul 2009 19:28:14 GMT
Alan Burlison <Alan.Burlison@Sun.COM> writes:

> Andrew Lawrenson wrote:
>
>> I'm not sure if it's the exact same issue, but I have observed the
>> replication failing under heavy load where the replication buffers
>> would fill faster than the logs can be shipped to the slave (even
>> with fast servers & fast network). I've previously tweaked a copy of
>> derby to allow up to 100 buffers (rather than the current max of 10),
>> and optimized the various thresholds, but still observed over 80
>> buffers being used under high load (this was with 10.4.2.0 on
>> Solaris).
>
> I think it is the same issue - I saw an errors in the master log that
> mentioned something about the buffers filling up.  The thing that
> seems to trigger it is doing a number of whole-table deletes,
> presumably because while that's being processed on the slave the
> master is still chugging along writing more log records.
>
> What I don't understand is why the master isn't being throttled if the
> slave can't keep up.

That sounds like DERBY-3719, which Dag fixed for the upcoming 10.5.2
release.

-- 
Knut Anders

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