Would a simple multi-column index be considered an 'expression' in this context, meaning that an ANALYZE should be issued after the creation of such an index?
--- Pete Yunker Vice President of Data Products Home Junction, Inc. On Oct 18, 2013, at 11:42 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > dinesh kumar <dineshkuma...@gmail.com> writes: >> When we create an index, i believe the postgres engine it self update it's >> catalog about the index availability. > > ANALYZE normally collects statistics about the contents of table columns. > Thus, adding (or removing) an index does not create any reason to > re-ANALYZE. > > However ... if you have an index on an expression (not just a simple > column value), that cues ANALYZE to collect statistics about the values of > that expression. So re-analyzing is useful after creating such an index, > to give the planner a better idea of when to use that index. > > Whether you used CREATE INDEX CONCURRENTLY or some other way of creating > the index doesn't matter at all. > > regards, tom lane > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
