Re: Insert performance

On 18 Aug 2003 at 18:52, Hannu Krosing wrote:
> My own experimentation also got numbers in 9k/sec range (on a quad
> 1.3GHz Xeons, 2GM mem, 50MB/sec raid) when doing 10-20 parallel runs of
> ~1000 inserts/transaction.
>
> Performance dropped to ~300/sec (at about 60M rows) when I added an
> index (primary key) - as I did random inserts, the hit rates for index
> pages were probably low.

I was loading a geographic data couple of months back.. It was 3GB data when
loaded in postgresql.

I tried loading data first and creating index later. It ran out of available
9GB space. So I created index on an empty table and started loading it. It was
slow but at least finished after 3 hours... Co-incidentally oracle had same
problems as well. So creating index beforehand remains only option at times, it
seems. Tom remarked that it shouldn't have made difference but apparently it
does..

You mentioned parallel runs and still getting 9K/sec. Was that overall 9K or
per connection? If it is former, probably WAL is hit too hard. You could do
some additional testing by having WALit's own disk.

I was plannning to do the multiple writers test. But since objective was to
find out why postgresql was so slow and it tunred out to be slowaris in first
place, didn't have any enthu. left.

I recommended my colleague to move to linux. But apparently this product is a
part of suit which runs on some HUGE solaris machines. So if it has to run
postgresql, it has to run sunos. I hope they are faster with SCSI..

Bye
Shridhar

--
On my planet, to rest is to rest -- to cease using energy. To me, itis quite
illogical to run up and down on green grass, using energy,instead of saving it.
-- Spock, "Shore Leave", stardate 3025.2