El 13/09/18 a las 18:39, Jesper Pedersen escribió:
Yes, this doesn't look good. Using your test case I'm seeing that unique is being chosen when the group size is below 34, and skip above. This is with the standard initdb configuration; did you change something else ? Or did you force the default plan ?
Sorry I didn't mention this, the first column is indeed forced skip scan, just to see how it compares to index scan.
This is something to look at -- maybe there is a way to use btpo_next/btpo_prev instead/too in order to speed things up. Atm we just have the scan key in BTScanOpaqueData. I'll take a look after my upcoming vacation; feel free to contribute those changes in the meantime of course.
I probably won't be able to contribute the changes, but I'll try to review them.
-- Alexander Kuzmenkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
