Re: Slow deletes

Thanks! That seems to have been the issue!

=> explain delete from syslog_event where event_id = 1000::int8;
NOTICE:  QUERY PLAN:

Index Scan using syslog_event_event_id_idx on syslog_event
(cost=0.00..3.02 rows=1 width=6)

EXPLAIN

Deleting a single row now takes only about 5 seconds.

Regards,
Ed

On Mon, 12 Aug 2002, Tom Lane wrote:

> Edmund Dengler <edmundd@eSentire.com> writes:
> > Can anyone explain why these deletes are extremely slow?
>
> > => explain delete from syslog_event where event_id = 1001;
> > NOTICE:  QUERY PLAN:
>
> > Seq Scan on syslog_event  (cost=0.00..342277.67 rows=1 width=6)
>
> > There are over 5,000,000 rows in the table.
>
> Seqscan on a 5M-row table will take a little while...
>
> Your problem is that it's not using an indexscan, and the reason
> for that is that '1001' is taken as an integer not a bigint.  The
> system is not smart about optimizing cross-datatype comparisons
> into indexscans.  You could write
>
> delete from syslog_event where event_id = 1001::int8;
>
> (or use CAST if you want to be pedantically standards-compliant).
> Alternatively, consider whether event_id really needs to be bigint.
> There's a clear notational advantage in plain integer.
>
> Yes, it'd be nice if "bigintcol = 1001" acted more reasonably,
> and someday we'll make it happen ... but doing so without breaking
> the system's type-extensibility features is not trivial.
>
>             regards, tom lane
>
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