Re: xlog.c: WALInsertLock vs. WALWriteLock - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: xlog.c: WALInsertLock vs. WALWriteLock
Date
Msg-id 1288191884-sup-5858@alvh.no-ip.org
Whole thread Raw
In response to Re: xlog.c: WALInsertLock vs. WALWriteLock  (Markus Wanner <markus@bluegap.ch>)
List pgsql-hackers
Excerpts from Markus Wanner's message of mié oct 27 11:44:20 -0300 2010:
> On 10/26/2010 05:52 PM, Alvaro Herrera wrote:
> > And horrible for performance, I imagine.  Those locks are highly trafficked.
> 
> Note, however, that offloading this to the file-system just moves
> congestion there. So we are effectively saying that we expect
> filesystems to do a better job (in that aspect) than our WAL implementation.

Well, you can just read at your pace from the filesystem; the data is
going to stay there for a long time.  WAL buffers are constantly moving,
and aren't as big.

-- 
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support


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