I don't think it even has to be so specific. We should just always
rewrite bool <> bool into bool = NOT bool.
Hmm. That only has a 50/50 chance of creating an indexable clause.
Perhaps we could even rewrite it as "a = NOT b AND NOT a = b".
--
Greg
On 2009-07-17, at 3:21 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
Peter Eisentraut <pete...@gmx.net> writes:
... But again, this is data type specific knowledge.
Actually, now that I think about it, the planner already has
datatype-specific knowledge about boolean equality (see
simplify_boolean_equality). It would take just a few more lines of
code
there to recognize "x <> true" and "x <> false" as additional variant
spellings of the generic "x" or "NOT x" constructs. Not sure if it's
worth the trouble though; how many people really write such things?
If you really wanted to take it to extremes, you could also reduce
cases like "x > false", but that's starting to get a bit silly.
regards, tom lane
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