2008/11/27 René-Etienne Muscat <remuscat <at> gmail.com>

Hi everyone, I have a problem with slony replicating slowly on a particular cluster.
This problem came up after slony replication had stopped for a weekend and this particular cluster (replication set) had a backlog of about 3million rows (about 1.2million on sl_log1 and 1.8million on sl_log2).

with that much of a backlog we often found that it's faster to rebuild slave nodes from scratch than to wait for "normal" catch up.

After resuming slony replication (it had a problem with a table locks), all the replication sets resumed normally (inserting over 15,000 rows per batch), except for this particular set.
When I examined the log for this set on the slave, I saw a lot of SYNC events, but few fetch/delivery events, and the inserts are just about 350rows each time.
I also noted that it was giving a lot of log switch failures ("log switch to sl_log_1 still in progress - sl_log_2 not truncated").
I first tried stopping all replication and starting replication on this problematic set, but still replication was slow (lots of SYNC events but very few fetch/delivery events).
I also tried to resolve the issue by stopping all replication and vacuuming the sl_logs, without any success.
Does anyone know why this is happening? Is this normal? Can I do somthing to speed this up?

which pg version? which slony-I version?
do you have all needed indexes on sl_log* in place?
did you try to REINDEX them? (they are probably "bloated")

I know it's a late reply but HTH.



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Filip Rembiałkowski