Re: [HACKERS] New FSM patch

Tom Lane wrote:
> Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
>> Let me describe this test case first:
>> - The test program calls RecordAndGetPageWithFreeSpace in a tight loop,
>> with random values.
>
> What's the distribution of the random values, exactly? In particular,
> how do the request sizes compare to available free space per-page?

The request, and "old avail" sizes are in the range of 0-8100
(random()%8100).

> The design intent for FSM was that we'd not bother to record pages that
> have less free space than the average request size, so as to (usually)
> avoid the problem of uselessly searching a lot of entries. I can't tell
> whether your test case models that behavior at all. If it does then
> there may be something else that needs fixing.

Probably not. The test case starts with a table that's practically
empty, so all pages are put into the FSM.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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