Subject Re: [firebird-support] Blob segment size and Filesystem block size
Author Ann W. Harrison
Nigel Weeks wrote:
> I was just wondering if having the segment size of BLOBs the same as the
> filesystem block sizes yields any benefits?
> Or does Firebird completely disregard the segment size when storing
> to;retrieving from disk.

Firebird totally ignores segment size. The attribute is available for
higher level programs as a suggested size for an allocated buffer. You
can, of course, choose the segment size you want to write. Typically
the engine writes everything up to 16K as a single segment.

Blobs are stored on database pages, making the segment size the same as
the file system block size will have no effect on the size of a write -
Firebird always writes page sized blocks. Making the segment size the
same as a page is also a bad idea, because the page has a certain amount
of overhead - about 20 bytes, if I remember, but subject to change.