Re: Huge difference between ASC and DESC ordering

Thank you Jeff.

There are 7 million rows satisfying fk_id_client = 20045. There is an index
on fk_id_client, now I added a composite (fk_id_client, id) index but that
did not help.

I see the point of what you are saying, but still don't understand how these
two situations (*asc* vs. *desc*) are not symmetrical. I mean, there /is/ an
ascending index on *JOB_MEMORY.id*, so why does it matter which end I am
picking the data from?

The thing is, even when I force Postgres to use the ascending index on *id*,
it's still orders of magnitude slower than the *desc* version (even when
that one goes through the index backwards).

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