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Re: [PERFORM] insert performance for win32

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
Cc: "Marc Cousin" <mcousin(at)sigma(dot)fr>,pgsql-performance(at)postgresql(dot)org, pgsql-hackers-win32(at)postgresql(dot)org
Subject: Re: [PERFORM] insert performance for win32
Date: 2005-09-07 15:02:13
Message-ID: 27312.1126105333@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers-win32pgsql-performance
"Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com> writes:
> ok, I've been in crunching profile profile graphs, and so far have been
> only been able to draw following conclusions.

> For bulk, 'in-transaction' insert:
> 1. win32 is slower than linux.  win32 time for each insert grows with #
> inserts in xact, linux does not (or grows much slower).  Win32 starts
> out about 3x slower and grows to 10x slower after 250k inserts.

Just to be clear: what you were testing was
	BEGIN;
	INSERT ... VALUES (...);
	repeat insert many times
	COMMIT;
with each statement issued as a separate PQexec() operation, correct?
Was this set up as a psql script, or specialized C code?  (If a psql
script, I wonder whether it's psql that's chewing the time.)

> 2. ran a 50k profile vs. 250k profile.  Nothing jumps out as being
> slower or faster: most time is spent in yyparse on either side.  From
> this my preliminary conclusion is that there is something going on in
> the win32 api which is not showing in the profile.

Hmm.  Client/server data transport maybe?  It would be interesting to
try inserting the same data in other ways:
	* COPY from client
	* COPY from disk file
	* INSERT/SELECT from another table
and see whether you see a similar slowdown.

			regards, tom lane

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