Hi Jan,
Just to add to the nightmare... Even though some queries are cursor
based, the postgres process can still run out of memory when
performing queries (I have seen this happen with slony).
Thanks,
Peter
Jan Wieck wrote:
On
12/8/2005 9:31 AM, [EMAIL PROTECTED] wrote:
On 12/7/2005 9:23 PM, Peter Davie wrote:
Hi All,
Using Slony1 version 1.1.0 at a customer site, the customer has had the
slon daemons fall over on one of their slave servers (and didn't
notice!) On restarting the slon processes, there is now an error being
generated because it is attempting to malloc memory to record all of
the
outstanding transactions and the slon daemon is running out of memory.
Is there any way forward to resolve this, or will I just have to
uninstall the slave and resubscribe (which is my current plan).
This node must have been down for quite some time. A SYNC event in the
remote_worker queue takes about 200 bytes or so. How many million
events
is this node behind? You could tell from looking at sl_status.
And don't forget to VACUUM FULL ANALYZE that database after you've
dropped that node.
Based on the symptoms, two things come to my mind:
1. Did the slon controlling the origin die? That would be the classic
way for a SYNC to encompass a Very Long Period Of Time and hence a LOT
of
transactions.
That's not the case and it wouldn't cause the symptom observed. Unless
there are large rows involved, the resulting, humungous sync chunk
would just take a while, but since that operation is cursor driven even
in 1.0, it won't cause slon to run out of memory.
There's a script in ~/tools that will generate SYNCs if you run it as a
cron job. We run this in production so as to avoid this particular
problem...
2. Is it possible that the subscriber is trying to process a whole
bunch
of SYNCs in one fell group?
If you add the "-g 1" option, it'll go one SYNC at a time, which would
somewhat alleviate the problem.
Would not be a problem either.
Jan
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