The allocations used for the static array ExplainExtensionOptionArray, that tracks a set of ExplainExtensionOption, used "char *" instead of ExplainExtensionOption as the memory size consumed by one element, underestimating the memory required by half. The initial allocation of ExplainExtensionNameArray wants to hold 16 elements before being reallocated, and with "char *" it meant that there was enough space only for 8 ExplainExtensionOption elements, 16 bytes required for each element. The backend would crash once one tries to register a 9th EXPLAIN option. As far as I can see, the allocation formulas of GetExplainExtensionId() have been copy-pasted to RegisterExtensionExplainOption(), but the internal maths of the copy were not adjusted accordingly. Oversight in c65bc2e1d14a. Author: Joel Jacobson <joel@compiler.org> Discussion: https://postgr.es/m/2a4bd2f5-2a2f-409f-8ac7-110dd3fad4fc@app.fastmail.com Backpatch-through: 18
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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.