: [EXT] Re: Query performance going from Oracle to Postgres
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On Thu, Sep 7, 2023 at 3:48 AM David Rowley wrote:
> On Thu, 7 Sept 2023 at 19:17, Peter Geoghegan wrote:
> > It seems likely that the problem here is that some of the p
On Thu, Sep 7, 2023 at 3:48 AM David Rowley wrote:
> On Thu, 7 Sept 2023 at 19:17, Peter Geoghegan wrote:
> > It seems likely that the problem here is that some of the predicates
> > appear as so-called "Filter:" conditions, as opposed to true index
> > quals.
>
> hmm, if that were true we'd see
On Thu, 7 Sept 2023 at 19:17, Peter Geoghegan wrote:
> It seems likely that the problem here is that some of the predicates
> appear as so-called "Filter:" conditions, as opposed to true index
> quals.
hmm, if that were true we'd see "Rows Removed by Filter" in the
explain analyze.
I think all t
On Wed, Sep 6, 2023 at 1:07 PM Dirschel, Steve
wrote:
> Oracle will find the same 332 rows using the same index but in Oracle it only
> does 20 logical reads. I thought maybe the index was fragmented so I
> reindexed that index:
It seems likely that the problem here is that some of the predica
On Thu, 7 Sept 2023 at 11:14, Dirschel, Steve
wrote:
> select count(historyeve0_.HISTORY_EVENT_SID) as col_0_0_ from
> hist28.history_event_display_timestamp_20230301 historyeve0_ where
> historyeve0_.IS_DELETED=0
> history_event_sid | character varying(32) | | not
> nu
On Wed, 2023-09-06 at 20:06 +, Dirschel, Steve wrote:
> We are in the process of converting from Oracle to Postgres and I have a
> query that is using
> the same index in Postgres as is used in Oracle but in Postgres the query
> does 16x more
> buffer/logical reads. I’d like to understand wh
We are in the process of converting from Oracle to Postgres and I have a query
that is using the same index in Postgres as is used in Oracle but in Postgres
the query does 16x more buffer/logical reads. I'd like to understand why. The
query is hitting a partitioned table but to simply things I
