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The previous coding of dshash_seq_next(), on the first call, accessed status->hash_table->size_log2 without holding a partition lock and without guaranteeing that ensure_valid_bucket_pointers() had ever been called. That oversight turns out to not have immediately visible effects, because bucket 0 is always in partition 0, and ensure_valid_bucket_pointers() was called after acquiring the partition lock. However, PARTITION_FOR_BUCKET_INDEX() with a size_log2 of 0 ends up triggering formally undefined behaviour. Simplify by accessing partition 0, without using PARTITION_FOR_BUCKET_INDEX(). While at it, remove dshash_get_current(), there is no convincing use case. Also polish a few comments. Author: Andres Freund <andres@anarazel.de> Reviewed-By: Thomas Munro <thomas.munro@gmail.com> Discussion: https://postgr.es/m/CA+hUKGL9hY_VY=+oUK+Gc1iSRx-Ls5qeYJ6q=dQVZnT3R63Taw@mail.gmail.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/.