32kb pagesize

[Tomasz Dubiel]

Hello.

When migrating from Firebird 3 to 5, how would you decide when choosing pagesize for a database which has only one table with one index (PK) and this table stores only blobs? (column with domain BLOB SUB_TYPE 0 SEGMENT SIZE 80)

Choosing always 32 kb? It depends on database size?

Best regards,

Tomek.

[Dimitry Sibiryakov]

Tomasz Dubiel wrote 10.12.2025 9:57:
> Choosing always 32 kb? It depends on database size?

If you have no other criteria - choose at least size of FS cluster or I/O
(file cache) unit.

--
WBR, SD.

[Mark Rotteveel]

I wouldn't, unless (most of) your blobs are close in size to multiples
of (32 KiB - x bytes) (where x is the overhead of the headers of a blob
page, which I don't know by heart), or if your PK index is very deep on
other page sizes.

Otherwise, you'll probably just waste more space, with (on average) half
empty blob pages for the last page of each blob.

As an aside, "segment size N" is pretty much irrelevant these days.

Mark
--
Mark Rotteveel