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Tom Lane efc77cf5f1 Fix intarray's GiST opclasses to not fail for empty arrays with <@. ... contrib/intarray considers "arraycol <@ constant-array" to be indexable, but its GiST opclass code fails to reliably find index entries for empty array values (which of course should trivially match such queries). This is because the test condition to see whether we should descend through a non-leaf node is wrong. Unfortunately, empty array entries could be anywhere in the index, as these index opclasses are currently designed. So there's no way to fix this except by lobotomizing <@ indexscans to scan the whole index ... which is what this patch does. That's pretty unfortunate: the performance is now actually worse than a seqscan, in most cases. We'd be better off to remove <@ from the GiST opclasses entirely, and perhaps a future non-back-patchable patch will do so. In the meantime, applications whose performance is adversely impacted have a couple of options. They could switch to a GIN index, which doesn't have this bug, or they could replace "arraycol <@ constant-array" with "arraycol <@ constant-array AND arraycol && constant-array". That will provide about the same performance as before, and it will find all non-empty subsets of the given constant-array, which is all that could reliably be expected of the query before. While at it, add some more regression test cases to improve code coverage of contrib/intarray. In passing, adjust resize_intArrayType so that when it's returning an empty array, it uses construct_empty_array for that rather than cowboy hacking on the input array. While the hack produces an array that looks valid for most purposes, it isn't bitwise equal to empty arrays produced by other code paths, which could have subtle odd effects. I don't think this code path is performance-critical enough to justify such shortcuts. (Back-patch this part only as far as v11; before commit 01783ac36 we were not careful about this in other intarray code paths either.) Back-patch the <@ fixes to all supported versions, since this was broken from day one. Patch by me; thanks to Alexander Korotkov for review. Discussion: https://postgr.es/m/458.1565114141@sss.pgh.pa.us		6 years ago
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bench	Don't fall off the end of perl functions	7 years ago
data	…
expected	Fix intarray's GiST opclasses to not fail for empty arrays with <@.	6 years ago
sql	Fix intarray's GiST opclasses to not fail for empty arrays with <@.	6 years ago
.gitignore	Support "make check" in contrib	15 years ago
Makefile	Handle contrib's GIN/GIST support function signature changes honestly.	9 years ago
_int.h	Fix inconsistencies and typos in the tree	6 years ago
_int_bool.c	Change TRUE/FALSE to true/false	8 years ago
_int_gin.c	Change TRUE/FALSE to true/false	8 years ago
_int_gist.c	Fix intarray's GiST opclasses to not fail for empty arrays with <@.	6 years ago
_int_op.c	Change TRUE/FALSE to true/false	8 years ago
_int_selfuncs.c	Fix many typos and inconsistencies	6 years ago
_int_tool.c	Fix intarray's GiST opclasses to not fail for empty arrays with <@.	6 years ago
_intbig_gist.c	Fix intarray's GiST opclasses to not fail for empty arrays with <@.	6 years ago
intarray--1.0--1.1.sql	Add selectivity estimation functions for intarray operators.	10 years ago
intarray--1.1--1.2.sql	Update extensions with GIN/GIST support for parallel query.	9 years ago
intarray--1.2.sql	Update extensions with GIN/GIST support for parallel query.	9 years ago
intarray--unpackaged--1.0.sql	Fix typos in some error messages thrown by extension scripts when fed to psql.	11 years ago
intarray.control	Handle contrib's GIN/GIST support function signature changes honestly.	9 years ago