Re: [HACKERS] WAL: parallel logging - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] WAL: parallel logging
Date
Msg-id 199907190431.AAA18856@candle.pha.pa.us
Whole thread Raw
In response to WAL: parallel logging  (Vadim Mikheev <vadim@krs.ru>)
Responses Re: [HACKERS] WAL: parallel logging  (Brian Bruns <camber@umcc.ais.org>)
List pgsql-hackers
> I don't see this feature in Oracle or Gray' book so I would
> like to know what do you think about ability to have more than
> 1 log to let different transactions write to different logs,
> in parallel. All log records from particular transaction will
> go in one log file (one fsync on commit). Transactions will
> choose log file to use in circle order. Each log record will have 
> unique id shared among all logs to order things.
> By placing logs on different disk one could significantly
> increase performance.

In most cases, the problem with log writes it not throughput, but
getting the disk head to the proper sector to fsync the data.

Someone said that large Sybase sites use a separate drive for logs, so
the head stays in the proper place to write the logs.

This is just a guess on my part.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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