7fd89f4d7a
Previously, AsyncShmemInit forcibly initialized the first page of the async SLRU, to save dealing with that case in asyncQueueAddEntries. But this is a poor tradeoff, since many installations do not ever use NOTIFY; for them, expending those cycles in AsyncShmemInit is a complete waste. Besides, this only saves a couple of instructions in asyncQueueAddEntries, which hardly seems likely to be measurable. The real reason to change this now, though, is that now that we track SLRU access stats, the existing code is causing the postmaster to accumulate some access counts, which then get inherited into child processes by fork(), messing up the statistics. Delaying the initialization into the first child that does a NOTIFY fixes that. Hence, we can revert f3d23d83e, which was an incorrect attempt at fixing that issue. Also, add an Assert to pgstat.c that should catch any future errors of the same sort. Discussion: https://postgr.es/m/8367.1589391884@sss.pgh.pa.us
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/.