RangeTblEntry.groupexprs was marked with the node attribute
query_jumble_ignore, causing a list of GROUP BY expressions to be
ignored during the query jumbling. For example, these two queries could
be grouped together within the same query ID:
SELECT count(*) FROM t GROUP BY a;
SELECT count(*) FROM t GROUP BY b;
However, as such queries use different GROUP BY clauses, they should be
split across multiple entries.
This fixes an oversight in 247dea89f7, that has introduced an RTE for
GROUP BY clauses. Query IDs are documented as being stable across minor
releases, but as this is a regression new to v18 and that we are still
early in its support cycle, a backpatch is exceptionally done as this
has broken a behavior that exists since query jumbling is supported in
core, since its introduction in pg_stat_statements.
The tests of pg_stat_statements are expanded to cover this area, with
patterns involving GROUP BY and GROUPING clauses.
Author: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEy2W+tCqC7XuJ94r3ivWsM=onKJp94kRFx3hoARjBeFQ@mail.gmail.com
Backpatch-through: 18
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.
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