Re: Explain plan for 2 column index - Mailing list pgsql-performance

From Tom Lane
Subject Re: Explain plan for 2 column index
Date
Msg-id 28616.1075414053@sss.pgh.pa.us
Whole thread Raw
In response to Re: Explain plan for 2 column index  (Richard Huxton <dev@archonet.com>)
List pgsql-performance
Richard Huxton <dev@archonet.com> writes:
>> Index Scan using testtab_name_date_from on testtab  (cost=0.00..2.01
>> rows=1 width=18)
>> Index Cond: ((name)::text = 'name1'::text)
>> Filter: ((date_from)::timestamp with time zone =
>> ('now'::text)::timestamp(6)with time zone)

> What types are the columns here? If date_from isn't timestamp with time zone,
> that might be the issue.

It clearly isn't, since we can see a coercion to timestamp with time
zone in the query.  My guess is that the original SQL was
    WHERE ... date_from = current_timestamp
This should be
    WHERE ... date_from = localtimestamp
if timestamp without tz is the intended column datatype.  Of course,
it might just be that date_from was declared as the wrong type (it
really sucks that SQL specifies "timestamp" to default to "without
time zone" ...)

            regards, tom lane

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