> De : pgsql-performance-owner@xxxxxxxxxxxxxx [mailto:pgsql-performance- > owner@xxxxxxxxxxxxxx] De la part de Ben > Envoyé : vendredi, juillet 28, 2006 15:21 > À : pgsql-performance@xxxxxxxxxxxxxx > Objet : [PERFORM] index usage > > I have a table with 37000 rows, an integer column, and an index on that > column. I've got a function that returns an integer. When I do a select > where I restrict that column to being equal to a static number, explain > tells me the index will be used. When I do the same thing but use the > function instead of a static number, explain shows me a full scan on the > table. > > I must be missing something, because my understanding is that the function > will be evaluated once for the statement and then collapsed into a static > number for the filtering. But the results of the explain seem to imply > that's not the case....? > Is your function IMMUTABLE, STABLE or VOLATILE? -- Daniel
