Re: [PERFORM] Re: Query > 1000× slowdown after adding datetime comparison

2015-08-31 21:46 GMT+02:00 twoflower <standa.kurik@gmail.com> wrote:
> I created a new boolean column and filled it for every row in DOCUMENT with
> *(doc.date_last_updated >= date(now() - '171:00:00'::interval))*, reanalyzed
> ...

... and you've put an index on that new boolean column (say "updated")?
CREATE INDEX index_name ON some_table (boolean_field);
or tried a conditional index like
CREATE INDEX index_name ON some_table (some_field) WHERE boolean_field;

-S.


2015-08-31 21:46 GMT+02:00 twoflower <standa.kurik@gmail.com>:
> David G Johnston wrote
>> What happens if you pre-compute the date condition and hard code it?
>
> I created a new boolean column and filled it for every row in DOCUMENT with
> *(doc.date_last_updated >= date(now() - '171:00:00'::interval))*, reanalyzed
> the table and modified the query to just compare this column to TRUE. I
> expected this to be very fast, considering that a (to me, anyway) similar
> query also containing a constant value comparison finishes immediately.
> However, the query is running now for 4 minutes already. That's really
> interesting.
>
>
>
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