Re: Slow count(*) again... - Mailing list pgsql-performance

From Tom Lane
Subject Re: Slow count(*) again...
Date
Msg-id 23516.1286891790@sss.pgh.pa.us
Whole thread Raw
In response to Re: Slow count(*) again...  (Mladen Gogala <mladen.gogala@vmsinfo.com>)
Responses Re: Slow count(*) again...
List pgsql-performance
Mladen Gogala <mladen.gogala@vmsinfo.com> writes:
> The number of rows is significantly smaller, but the table contains
> rather significant "text" field which consumes quite a bit of TOAST
> storage and the sizes are comparable. Postgres read through 27GB in 113
> seconds, less than 2 minutes and oracle took 2 minutes 37 seconds to
> read through 35GB.  I stand corrected: there is nothing wrong with the
> speed of the Postgres sequential scan.

Um ... the whole point of TOAST is that the data isn't in-line.
So what Postgres was actually reading through was probably quite a
lot less than 27Gb.  It's probably hard to make a completely
apples-to-apples comparison because the two databases are so different,
but I don't think this one proves that PG is faster than Oracle.

            regards, tom lane

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