Re: When did we get to be so fast?

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > I was just testing the threaded ecpg, and ran some performance tests.
> > Without using threads, I am seeing 100,000 inserts of a single word into
> > a simple table take 12 seconds:
> > CREATE TABLE test_thread(message TEXT);
> > giving me 8333 inserts per second. That seems very high.
>
> Single transaction, or one transaction per INSERT?

This is ecpg, and I didn't have AUTOCOMMIT on, so it was a single
transaction. I had forgotten that.

Also, I was wrong in my computations. It is 4166 inserts per second,
not 8333. Sorry.

I am now seeing more reasonable numbers:

one INSERT per transaction, fsync true 934
one INSERT per transaction, fsync false 1818
one INSERT per transaction, fsync true 4166

> With the present WAL design, it's not possible for one backend to commit
> more than one transaction per disk rotation --- unless fsync is off, or
> your disk drive lies about write-complete. Given that you recently
> updated your hardware, I'm betting on the last item ...

Yep.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073