Re: Q: Redo Log Switching

From: Martin Haltmayer <Martin_Haltmayer_at_KirchGruppe.de>
Date: 1997/10/31
Message-ID: <34599CB9.310E7F1B@KirchGruppe.de>#1/1

Dear Andreas,

the redolog buffer is not flushed when it is full but earlier: if it is one third full, or if you do a commit or a rollback or a shutdown normal/immediate.

Andreas Hess wrote:
>
> Q1: Why does a log switch need to occur just because
> there is no available space in the buffer ? Why can't
> the buffer be flushed to an online redo log file without
> triggering a log switch ?

Some misconception here: flushing of the redolog buffer won't cause a log
switch. If this were the case, you could not work with your database because you would permanently log switch (see above).

>
> Q2: Would a large redo log buffer reduce the number of
> log switches ?

See above. No, it won't.

>
> Q3: Follow on to Q2 - would a log buffer which is > the
> online redo log file be the most efficient ?
>
> Q4: Am I missing the point here ?
>

Martin Haltmayer Received on Fri Oct 31 1997 - 00:00:00 CST