Re: BUG #18344: Pruning tables partitioned by bool range fails with invalid strategy

PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> The following query:
> CREATE TABLE t (b bool, i int) PARTITION BY RANGE (b, i);
> CREATE TABLE tp PARTITION OF t FOR VALUES FROM (false, 0) TO (false, 1);
> SELECT * FROM t WHERE b IS NOT true;
> fails with ERROR: invalid strategy number 0.
> Reproduced on REL_12_STABLE .. master.
> The first bad commit for this anomaly is e0693faf7.

What seems to be happening is that gen_prune_step_op is getting
op_is_ne = true and doing this:

/*
* For clauses that contain an <> operator, set opstrategy to
* InvalidStrategy to signal get_matching_list_bounds to do the right
* thing.
*/
opstep->opstrategy = op_is_ne ? InvalidStrategy : opstrategy;

but then we're failing in get_matching_range_bounds, ie somebody
taught get_matching_list_bounds to do the right thing but not
any of the other code paths.

I'm also wondering how we got there in the first place. It looks like
match_boolean_partition_clause thinks it can translate "b IS NOT true"
to "b <> true", which is flat wrong --- it gives the wrong result for
null.

regards, tom lane