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Commit 45f6240a8fa9d355 added an assumption in ExecHashIncreaseNumBatches and ExecHashIncreaseNumBuckets that they could find all tuples in the main hash table by iterating over the "dense storage" introduced by that patch. However, ExecHashRemoveNextSkewBucket continued its old practice of simply re-linking deleted skew tuples into the main table's hashchains. Hence, such tuples got lost during any subsequent increase in nbatch or nbuckets, and would never get joined, as reported in bug #13908 from Seth P. I (tgl) think that the aforesaid commit has got multiple design issues and should be reworked rather completely; but there is no time for that right now, so band-aid the problem by making ExecHashRemoveNextSkewBucket physically copy deleted skew tuples into the "dense storage" arena. The added test case is able to exhibit the problem by means of fooling the planner with a WHERE condition that it will underestimate the selectivity of, causing the initial nbatch estimate to be too small. Tomas Vondra and Tom Lane. Thanks to David Johnston for initial investigation into the bug report.
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: http://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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.