Re: rollback question

From: Norbert Ferstl <ferstl_at_netway.at>
Date: 1997/10/09
Message-ID: <343D12C7.E58EF2A0@netway.at>#1/1

Chuck Hamilton wrote:
>
> Someone recently told me that all rollback extents for a transaction must
> be contiguous. If a transaction attempts to allocate the next RBS extent,
> and that extent was already assigned to another transaction, that the first
> transaction will fail with a "snapshot too old" error. It will not skip
> over that extent and grab the next one. Is this true?
> --
> Chuck Hamilton
> Xchuckh_at_dvol.com
>
> In an effort to reduce spam, my return address has been altered.
> To reply, remove the X from the address.

You are wrong

1. extents must not be contiguos but every extent can only hold one transaction at one time
2. snapshot too old occurs if a consistent read cannot get consistent data previous to a commited transaction, that has not been commited at the start of the consistent read.

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Norbert Ferstl
DI Forsthuber GmbH
Kohlbauernstr. 17
A-2630 Ternitz, AUSTRIA
Tel: +43 2630 382500
Fax: +43 2630 3825014
<ferstl_at_netway.at>

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Received on Thu Oct 09 1997 - 00:00:00 CDT