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In the planner, it was possible, given an extreme enough case containing a large number of joins for the number of estimated rows to become infinite. This could cause problems in initial_cost_mergejoin() where we perform some calculations based on those row estimates. A problem case, presented by Onder Kalaci showed an Assert failure from an Assert checking outerstartsel <= outerendsel. In his test case this was effectively NaN <= Inf, which is false. The NaN outerstartsel came from multiplying the infinite outer_path_rows by 0.0. In master, this problem was fixed by a90c950fc, however, that fix was too invasive for the backbranches. Here we just relax the Asserts to allow them to pass. The worst that appears to happen from this is that we show NaN cost values and infinite row estimates in EXPLAIN. add_path() would have had a hard time doing anything useful with such costs, but that does not really matter as if the row estimates were even close to accurate, such plan would not complete this side of the heat death of the universe. Reported-by: Onder Kalaci Backpatch: 9.5 to 13 Discussion: https://postgr.es/m/DM6PR21MB1211FF360183BCA901B27F04D80B0@DM6PR21MB1211.namprd21.prod.outlook.com
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/.