69059d3b2f
Since the CLOG page number is not recorded directly in the checkpoint record, we have to use ShmemVariableCache->nextXid to figure out the latest CLOG page number at the start of recovery. However, as recovery progresses, replay of CLOG/EXTEND records will update our notion of the latest page number, and we should rely on that being accurate rather than recomputing the value based on an updated notion of nextXid. ShmemVariableCache->nextXid is only an approximation during recovery anyway, whereas CLOG/EXTEND records are an authoritative representation of how the SLRU has been updated. Commit 0fcc2decd485a61321a3220d8f76cb108b082009 makes this simplification possible, as before that change clog_redo() might have injected a bogus value here, and we'd want to get rid of that before entering normal running. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@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/.