Hi Floris,
On 6/1/19 12:10 AM, Floris Van Nee wrote:
Given a table definition of (market text, feedcode text, updated_at
timestamptz, value float8) and an index on (market, feedcode, updated_at desc)
(note that this table slightly deviates from what I described in my previous
mail) and filling it with data.
The following query uses an index skip scan and returns just 1 row (incorrect!)
select distinct on (market, feedcode) market, feedcode
from streams.base_price
where market='TEST'
The following query still uses the regular index scan and returns many more
rows (correct)
select distinct on (market, feedcode) *
from streams.base_price
where market='TEST'
It seems that partially filtering on one of the distinct columns triggers
incorrect behavior where too many rows in the index are skipped.
Thanks for taking a look at the patch, and your feedback on it.
I'll def look into this once I'm back from my travels.
Best regards,
Jesper
