On 23 November 2016 at 21:19, Thomas Munro <thomas.mu...@enterprisedb.com> wrote: > Worth pursuing? Does amskip suck? Does anyone have better ideas, > either for how to do the low level skip or the higher level Index Skip > Scan, or perhaps a completely different way of looking at this?
I have no helpful suggestions with how to achieve it, but can I add a voice of encouragement: there have been a good few occasions in the past year (we moved from another db to PG) where the lack of skip scans has bitten us; in that case it was using MIN() and GROUP BY, where the grouping column was the first element in the compound index and the aggregate column was the second: in the Other DB that sort of query was extremely quick, not so much here. I was also idly pondering (in one of those moments of conceited self-delusion where I thought I might actually have enough spare time to try to work on it myself) whether it would be possible to implement that sort of skip with two indexes (so MIN(a) GROUP BY b with separate indexes on (a) and (b) rather than a single index (a,b)); I never got much further than idle musings though. Geoff -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers