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Tom Lane 99419d36f2 Allow predicate_refuted_by() to deduce that NOT A refutes A. ... We had originally made the stronger assumption that NOT A refutes any B if B implies A, but this fails in three-valued logic, because we need to prove B is false not just that it's not true. However the logic does go through if B is equal to A. Recognizing this limited case is enough to handle examples that arise when we have simplified "bool_var = true" or "bool_var = false" to just "bool_var" or "NOT bool_var". If we had not done that simplification then the btree-operator proof logic would have been able to prove that the expressions were contradictory, but only for identical expressions being compared to the constants; so handling identical A and B covers all the same cases. The motivation for doing this is to avoid unexpected asymmetrical behavior when a partitioned table uses a boolean partitioning column, as in today's gripe from Dominik Sander. Back-patch to 8.2, which is as far back as predicate_refuted_by attempts to do anything at all with NOTs.		16 years ago
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Makefile	Add a concept of "placeholder" variables to the planner. These are variables	17 years ago
clauses.c	Wrap calls to SearchSysCache and related functions using macros.	16 years ago
joininfo.c	Update copyright for the year 2010.	16 years ago
pathnode.c	Update copyright for the year 2010.	16 years ago
placeholder.c	Update copyright for the year 2010.	16 years ago
plancat.c	Support ALTER TABLESPACE name SET/RESET ( tablespace_options ).	16 years ago
predtest.c	Allow predicate_refuted_by() to deduce that NOT A refutes A.	16 years ago
relnode.c	Update copyright for the year 2010.	16 years ago
restrictinfo.c	Update copyright for the year 2010.	16 years ago
tlist.c	Update copyright for the year 2010.	16 years ago
var.c	Update copyright for the year 2010.	16 years ago