Dear Tom,
On Thu, Apr 14, 2011 at 10:10:44AM -0400, Tom Lane wrote:
> =?iso-8859-1?Q?V=E1clav_Ovs=EDk?= writes:
> > I'm not certain about your sentence touching int4eq() and index. The
> > execution plan as show in my previous mail contains information about
> > using index tickets5:
>
> >
hi.
>I think you're missing the point, which is that all the hash work is
>just pure overhead in such a case (and it is most definitely not
>zero-cost overhead). You might as well just do a nestloop join.
>Hashing is only beneficial to the extent that it allows a smaller subset
>of the inner rela
We are experiencing a problem with our query plans when using a range
query in Postgresql 8.3. The query we are executing attempts to select
the minimum primary key id after a certain date. Our date columns are
bigint's holding a unix epoch representation of the date. We have an
index on the pr
On Fri, Apr 15, 2011 at 10:17:32AM -0700, Mark Williams wrote:
> We are experiencing a problem with our query plans when using a range query
> in Postgresql 8.3. The query we are executing attempts to select the
> minimum primary key id after a certain date. Our date columns are bigint's
> holdi
Mark Williams wrote:
> explain SELECT min(messageID) FROM Message
> WHERE modificationDate >= 1302627793988;
> For some reason it is deciding to scan the primary key column of
> the table. This results in scanning the entire table
No, it scans until it finds the first row where modificatio
Thanks for the response guys. There is something else which confuses me.
If I re-write the query like this:
explain SELECT messageID FROM Message WHERE modificationDate >=
1302627793988 ORDER BY modificationDate LIMIT 1;
QUERY PLAN
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Mark Williams wrote:
> If I re-write the query like this:
>
> explain SELECT messageID FROM Message WHERE modificationDate >=
> 1302627793988 ORDER BY modificationDate LIMIT 1;
> I also get a better plan.
Yeah, but it's not necessarily the same value. Do you want the
minimum messageID whe
Whoops,
I meant this query (ordering my messageid):
SELECT messageID FROM Message WHERE modificationDate>= 1302627793988 ORDER BY
messageID LIMIT 1;
Sometimes this gives the better plan. But not always.
On 04/15/2011 11:13 AM, Kevin Grittner wrote:
Mark Williams wrote:
If I re-write th
