Re: FSM patch - performance test

Tom Lane wrote:
> Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
>> Zdenek Kotala wrote:
>>> My conclusion is that new implementation is about 8% slower in OLTP
>>> workload.
>
>> Thanks. That's very disappointing :-(
>
> One thing that jumped out at me is that you call FreeSpaceMapExtendRel
> every time a rel is extended by even one block. I admit I've not
> studied the data structure in any detail yet, but surely most such calls
> end up being a no-op? Seems like some attention to making a fast path
> for that case would be helpful.

Yes, most of those calls end up being no-op. Which is exactly why I
would be surprised if those made any difference. It does call
smgrnblocks(), though, which isn't completely free...

Zdenek, can you say off the top of your head whether the test was I/O
bound or CPU bound? What was the CPU utilization % during the test?

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