RE: v7.1 & WAL

From: "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>
To: "'Peter Schmidt'" <peterjs(at)home(dot)com>, pgsql-admin(at)postgresql(dot)org
Subject: RE: v7.1 & WAL
Date: 2001-01-11 19:49:45
Message-ID: 8F4C99C66D04D4118F580090272A7A234D3260@sectorbase1.sectorbase.com
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> The 7.1 Release notes include the statement re WAL below.
>
> "Write-ahead Log (WAL)
> To maintain database consistency in case of an operating system crash,
> previous releases of PostgreSQL have forced all data modifications to
> disk before each transaction commit. With WAL, only one log file
> must be flushed to disk, greatly improving performance. If you have been
> using -F in previous releases to disable disk flushes, you may want to
> consider discontinuing its use."
>
> Have WAL changes had any impact on vacuum?

No.

> Are there other benefits gained from these changes? e.g. less
> likely to see a corrupted database in the event of a system crash,

Yes (there was posting to -general about non-atomic disk writes).

> performance gains, etc?

Sure, in multi-user environment.

> Where is the new WAL log - pg_log no longer exists?

pg_log still exists. WAL logs are in pg_xlog dir.

Vadim

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