
When an aggregate function is used as a WindowFunc and a tuple transitions out of the window frame, we ordinarily try to make use of the aggregate function's inverse transition function to "unaggregate" the exiting tuple. This optimization is disabled for various cases, including when the aggregate contains a volatile function. In such a case we'd be unable to ensure that the transition value was calculated to the same value during transitions and inverse transitions. Unfortunately, we did this check by calling contain_volatile_functions() which does not recursively search SubPlans for volatile functions. If the aggregate function's arguments or its FILTER clause contained a subplan with volatile functions then we'd fail to notice this. Here we fix this by just disabling the optimization when the WindowFunc contains any subplans. Volatile functions are not the only reason that a subplan may have nonrepeatable results. Bug: #17777 Reported-by: Anban Company Discussion: https://postgr.es/m/17777-860b739b6efde977%40postgresql.org Reviewed-by: Tom Lane Backpatch-through: 11
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.
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