On 03/02/2015 09:29 PM, Peter Geoghegan wrote:
On Mon, Mar 2, 2015 at 11:20 AM, Heikki Linnakangas <hlinn...@iki.fi> wrote:
Are we OK with a 10% overhead, caused by the locking? That's probably
acceptable if that's what it takes to get UPSERT. But it's not OK just to
solve the deadlock issue with regular insertions into a table with exclusion
constraints. Can we find a scheme to eliminate that overhead?
Looks like you tested a B-Tree index here. That doesn't seem
particularly representative of what you'd see with exclusion
constraints.
Hmm. I used a b-tree to estimate the effect that the locking would have
in the UPSERT case, for UPSERT into a table with a b-tree index. But
you're right that for the question of whether this is acceptable for the
case of regular insert into a table with exclusion constraints, other
indexams are more interesting. In a very quick test, the overhead with a
single GiST index seems to be about 5%. IMHO that's still a noticeable
slowdown, so let's try to find a way to eliminate it.
- Heikki
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