/*------------------------------------------------------------------------- * * catversion.h * "Catalog version number" for PostgreSQL. * * The catalog version number is used to flag incompatible changes in * the PostgreSQL system catalogs. Whenever anyone changes the format of * a system catalog relation, or adds, deletes, or modifies standard * catalog entries in such a way that an updated backend wouldn't work * with an old database (or vice versa), the catalog version number * should be changed. The version number stored in pg_control by initdb * is checked against the version number compiled into the backend at * startup time, so that a backend can refuse to run in an incompatible * database. * * The point of this feature is to provide a finer grain of compatibility * checking than is possible from looking at the major version number * stored in PG_VERSION. It shouldn't matter to end users, but during * development cycles we usually make quite a few incompatible changes * to the contents of the system catalogs, and we don't want to bump the * major version number for each one. What we can do instead is bump * this internal version number. This should save some grief for * developers who might otherwise waste time tracking down "bugs" that * are really just code-vs-database incompatibilities. * * The rule for developers is: if you commit a change that requires * an initdb, you should update the catalog version number (as well as * notifying the pgsql-hackers mailing list, which has been the * informal practice for a long time). * * The catalog version number is placed here since modifying files in * include/catalog is the most common kind of initdb-forcing change. * But it could be used to protect any kind of incompatible change in * database contents or layout, such as altering tuple headers. * * * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/catalog/catversion.h * *------------------------------------------------------------------------- */ #ifndef CATVERSION_H #define CATVERSION_H /* * We could use anything we wanted for version numbers, but I recommend * following the "YYYYMMDDN" style often used for DNS zone serial numbers. * YYYYMMDD are the date of the change, and N is the number of the change * on that day. (Hopefully we'll never commit ten independent sets of * catalog changes on the same day...) */ /* yyyymmddN */ #define CATALOG_VERSION_NO 202107181 #endif