Re: ANALYZE locks pg_listener in EXCLUSIVE for long

Further to this, ProcessIncomingNotify seems to hold the lock on the
listener relation until it's current transaction exits. If the ANALYZE was
not the source of the error, but was just another victim, does that mean it
might hold the lock for a very long time if the analyze is lengthy?

At 02:54 PM 3/05/2004, Tom Lane wrote:
>Please dig deeper.

I may have found the problem; all the hung processes show 'async_notify
waiting' in ps, and the ANALYZE eventually dies with 'tuple concurrently
updated'.

The routine 'ProcessIncomingNotify' in async.c does indeed try to lock
pg_listener (even if we're not using NOTIFY/LISTEN). Not sure why the
ANALYZE is locking the relation, though...but it is locked in AccessShareLock.

I can send a log of my investigations if necessary.

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