On 06/26/2013 04:10 PM, Yuri Levinsky wrote: > You typically don't want to use b-tree index when yo select > more when ~1-2% of your data.
Agreed. Indices on columns with very low selectivity don't perform well. (Postgres knows that and uses a sequential scan based on selectivity estimates. Being able to eliminate entire partitions from such a seq scan would certainly be beneficial, yes.) In the Postgres world, though, I think CLUSTERing might be the better approach to solve that problem. (Note: this has nothing to do with distributed systems in this case.) I'm not sure what the current status of auto clustering or optimized scans on such a permanently clustered table is, though. The minmax indices proposed for 9.4 might be another feature worth looking at. Both of these approaches may eventually provide a more general and more automatic way to speed up scans on large portions of a relation, IMO. Regards Markus Wanner -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
