Subject Re: [Firebird-Architect] blobs causes table fragmentation.
Author Arno Brinkman

> As I understand current behavior, blobs less than 256 bytes are
> stored at the same data page, in record. If blob is bigger it
> is stored at blob page, not data page.

Is this hard-coded limited by 256?

> There are some systems that store blobs with different size,
> so blob data is spreaded between data and blob pages.
> This makes table more "fragmented" and seriously slowdown
> record retrieval if 'select' does not selects blob fields.

Do you meant blob-data expands record-length and due that more data-pages
are used for the records?

> The suggestion is - to add some header page flag that
> will disable blob storing at data page.
> Of course, this flag will cause small blobs to be at the whole
> blob page, and db space will be less used. But anyway, this
> will speedup record retrieval.
> p.s. Also, I think (don't know the code) this will be faster
> than trying to fit blob into the data page.

IIRC blobs aren't compressed.
Beside your solution it would be usefull to compress blobs (that fit into
data-page) also.

Arno Brinkman

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