Martin Lesser <ml-pgsql@xxxxxxxxxxxx> writes: > I try to partition a large table (~ 120 mio. rows) into 50 smaller > tables but using the IMO immutable %-function constraint exclusion > does not work as expected: The constraint exclusion mechanism is not as bright as you think. There are some very limited cases where it can make a deduction that a WHERE clause implies a CHECK constraint that's not an exact textual equivalent ... but all those cases have to do with related b-tree operators, and % is not one. It's usually better to use partitioning rules that have something to do with the WHERE-clauses you'd be using anyway. For instance, try to partition on ranges of id1 instead of id1 % 50. That works because the CHECK clauses will be like "id1 >= x and id1 < y" and those operators are btree-related to the "id1 = z" clauses you'll have in the query. regards, tom lane
