Re: system usage stats (Was: Re: Why Not MySQL? )

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: The Hermit Hacker <scrappy@hub.org>
Cc: Mitch Vincent <mitch@huntsvilleal.com>, pgsql-hackers@postgresql.org
Date: 2000-05-04T05:47:32Z
Lists: pgsql-hackers
The Hermit Hacker <scrappy@hub.org> writes:
> Now, Mitch's results for v7.0 showed something like:
> 0/12 filesystem blocks in/out
> You intepreted that as 12 reads from the file system ... 'out' I would
> have interpreted as writes to the file system, which made zero sense
> ... do we have our 'in/out's backwards here?

Good point.  Writes from a SELECT are certainly possible --- the SELECT
could be writing tuple status-flag updates, if it was the first
transaction to verify commit status of tuples created by a prior
transaction.  But that again raises the issue of whether we've got
a fair comparison.  The 6.5 test apparently only saw already-marked-
committed tuples ...

			regards, tom lane