>     SELECT <blah>
>     IF <some circumstance that happens about 1/8th of the time>
>         BEGIN
>             INSERT
>                or
>             UPDATE
>         COMMIT;
>
> He says his current h/w peaks at 1/10th that rate.
>
> My question is: is that current peak rate ("300 inserts/updates
> *or* 2500 selects") based upon 1 connection, or many connections?
> With 4 CPUs, and a 4 disk RAID10, I wouldn't be surprised if 4 con-
> current connections gives the optimum speed.

Well it's more like each user interaction looks like:

        SELECT
        SELECT
        SELECT
        SELECT
        SELECT
        SELECT
        INSERT
        SELECT
        SELECT
        SELECT
        SELECT
        INSERT
        SELECT
        SELECT
        SELECT
        UPDATE
        SELECT
        SELECT
        UPDATE
        SELECT

And concurrency is very high, because it's a web app, and each httpd has one 
connection to PG, and there can be hundreds of active
httpd processes.  Some kind of connection pooling scheme might be in order when there 
are that many active clients.  Any views?



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TIP 9: the planner will ignore your desire to choose an index scan if your
      joining column's datatypes do not match

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