Excerpts from Jeff Janes's message of mar oct 26 12:22:38 -0300 2010: > I don't think that holding WALWriteLock accomplishes much. It > prevents part of the buffer from being written out to OS/disk, and > thus becoming eligible for being overwritten in the buffer, but the > WALInsertLock prevents it from actually being overwritten. And what > if the part of the buffer you want to read was already eligible for > overwriting but not yet actually overwritten? WALWriteLock won't > allow you to safely access it, but WALInsertLock will (assuming you > have a safe way to identify the record in the first place). For > either case, holding it in shared mode would be sufficient.
And horrible for performance, I imagine. Those locks are highly trafficked. -- Álvaro Herrera <alvhe...@commandprompt.com> The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
