Subject Re: [Firebird-Architect] Re: Fw: Performance
Author Daniel Rail
Hello eric_ck_leung,

Wednesday, June 25, 2003, 3:25:26 AM, you wrote:
> I am wondering if FB allows users to specify any BLOB fields being
> stored to any external files or storage devices.

Because of the multi-generational architecture of Firebird, it would
be hard to do this.

> I think if blob fields and other fields share the same storage
> pages. After prolong inserts, updates and deletes operations, And
> Blob fields are usually have irregular length, the pages might then
> be fragement greatly. And the database efficiency might be lowered.

Blobs have their own pages and it's only an 8 byte pointer, that
points to the blob, that is stored with the fields in a table. So, as
you can see, you wouldn't see fragments as you might expect. A blob
can cover more than one page depending on the blob size and the page
size, but those pages are not the same one where the records of the
table are stored. And as Jim mentioned in a previous message, the
blob is only retrieved when referenced.

Best regards,
Daniel Rail
Senior System Engineer
ACCRA Group Inc. (
ACCRA Med Software Inc. (