Hi. We recently started testing with slony 1.0.5, and we are seeing our
slon exit every once in a while with the error in the log:
 
FATAL cleanupThread: "vacuum analyze "_tzreplic".sl_event; vacuum
analyze "_tzreplic".sl_confirm; vacuum analyze "_tzreplic".sl_set
sync; vacuum analyze "_tzreplic".sl_log_1; vacuum analyze
"_tzreplic".sl_log_2;vacuum analyze "_tzreplic".sl_seqlog;vacuum analyze
p
g_catalog.pg_listener;" - ERROR: tuple concurrently updated
DEBUG1 main: scheduler mainloop returned
DEBUG1 syncThread: thread done
DEBUG1 localListenThread: thread done
DEBUG1 main: done
 
So, pg_listener was added to list of tables to be vacuumed in 1.0.5,
which seems to be causing this problem (the database log indicates the
error is coming from the vacuum on this table).
 
The connection being used in cleanup_thread does not appear to be in a
serialized transaction so I assume that is coming from vacuum itself?
Our application uses listen/notify in different places, so it's entirely
possible that pg_listener could get updated during cleanup_thread
processing.
 
I understand why pg_listener was added to the vacuum list, but I'm
wondering if the response to an error from this command should be a
process exit? Perhaps the error handling could be more granular to take
into account the concurrent update case?
 
- DAP
======================================================
David Parker    Tazz Networks
 
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