Subject Re[4]: [Firebird-Architect] blobs causes table fragmentation. TEST+LONG
Author Dmitry Kuzmenko
Hello, Arno!

Tuesday, October 5, 2004, 12:10:12 PM, you wrote:

AB> Certainly a interesting point. Calculated cardinality is in fact depending
AB> on if a BLOB needs to be fetched yes or no.
AB> Also does the used record-size for calculating cardinality include average
AB> blob-size, i'm afraid not.
AB> Thus with any BLOB, cardinality could be to far away from reality.

I was a bit wrong and think no. cardinality is used to understand
cost of i/o for that table, yes? So here we have correct
information. But if we try to

average_data_pages div record_size_from_rdb$format =

record_count, of course, will be wrong. But correct for optimizer
to decide is that table big or not.

Dmitri Kouzmenko