Subject Re: Odp: [firebird-support] Request for advice
Author Mark Rotteveel
On Fri, 25 Apr 2014 07:01:31 +0200, Thomas Beckmann
<thomas.beckmann@...> wrote:
> You are right: Blobs are stored in separate pages. But having blob
> fields inside tables with other fields forces these pages to be
> allocated when record is created - whether the blob will contain data or
> not.

Blob pages are only allocated when a blob is created and filled, so if you
insert a record where the blob field is null, then no additional pages get

> Furthermore, common (bad) practice of fetching all fields (select *
> from), sometimes even performed by database access layer of programming
> language against the developers wish, accesses this data and decreases
> performance.

That is only if you actually access the blob (as in: get the blob id and
then proceed to load the blob), or use an access component that does this
automatically for you.