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Re: LISTEN / NOTIFY performance in 8.3

From: Joel Stevenson <jrs_1(at)mac(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: LISTEN / NOTIFY performance in 8.3
Date: 2008-02-25 16:48:20
Message-ID: p06240807c3e8a18faa42@[192.168.0.9] (view raw, whole thread or download thread mbox)
Thread:
Lists: pgsql-performance
>Also, it might be worth enabling log_lock_waits to see if the slow
>notifies are due to having to wait on some lock or other.

Turning on log_lock_waits shows that there is a lot of waiting for 
locks on the pg_listener table ala:

process 22791 still waiting for ExclusiveLock on relation 2614 of 
database 16387 after 992.397 ms
...
process 22791 acquired ExclusiveLock on relation 2614 of database 
16387 after 1433.152 ms

deadlock_timeout is left at the default 1s setting.

Though these are being generated during application activity - 
running the simulation script does produce 300ms - 600ms NOTIFY 
statements but doesn't (at the moment) trigger a lock_wait log entry.

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Subject: Re: Q on views and performance
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