Subject | Re: [Firebird-Architect] blobs causes table fragmentation. |
---|---|
Author | Ann W. Harrison |
Post date | 2004-10-05T16:39:46Z |
>At 06:26 AM 10/5/2004, Pavel Cisar wrote:
>On 5 Oct 2004 at 10:27, Dmitry Yemanov wrote:
>
> > We have the very similar problem with "reserve" option in DPM. The engine
> > reserves up to 50% of the data page space for the subsequent updates.
>No, reserve is 20%.Sorry Pavel, the reserved space is one fragmented record header (16 bytes)
per primary* record stored on the page. With very large records, that's a
small percentage. With one character records, it's over 50%. And yes, it
might make sense to make the fill factor a table parameter rather than
a database parameter.
Regards,
Ann
* primary records - the record version pointed to by the record id and index.
Fragments, back versions, and blobs don't count.