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c7597a1d36
Commit 0f21db36d made an assumption that GIN triConsistentFns would not modify their input entryRes[] arrays. But in fact, the "shim" triConsistentFn that we use for opclasses that don't supply their own did exactly that, potentially leading to wrong answers from a GIN index search. Through bad luck, none of the test cases that we have for such opclasses exposed the bug. One response to this could be that the assumption of consistency check functions not modifying entryRes[] arrays is a bad one, but it still seems reasonable to me. Notably, shimTriConsistentFn is itself assuming that with respect to the underlying boolean consistentFn, so it's sure being self-centered in supposing that it gets to do so. Fortunately, it's quite simple to fix shimTriConsistentFn to restore the entry-time state of entryRes[], so let's do that instead. This issue doesn't affect any core GIN opclasses, since they all supply their own triConsistentFns. It does affect contrib modules btree_gin, hstore, and intarray. Along the way, I (tgl) noticed that shimTriConsistentFn failed to pick up on a "recheck" flag returned by its first call to the boolean consistentFn. This may be only a latent problem, since it would be unlikely for a consistentFn to set recheck for the all-false case and not any other cases. (Indeed, none of our contrib modules do that.) Nonetheless, it's formally wrong. Reported-by: Vinod Sridharan <vsridh90@gmail.com> Author: Vinod Sridharan <vsridh90@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/CAFMdLD7XzsXfi1+DpTqTgrD8XU0i2C99KuF=5VHLWjx4C1pkcg@mail.gmail.com Backpatch-through: 13
The PostgreSQL contrib tree
---------------------------
This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree. This does not preclude their
usefulness.
User documentation for each module appears in the main SGML
documentation.
When building from the source distribution, these modules are not
built automatically, unless you build the "world" target. You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.
Some directories supply new user-defined functions, operators, or
types. To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command. In a fresh database,
you can simply do
CREATE EXTENSION module_name;
See the PostgreSQL documentation for more information about this
procedure.