dab421d2f0
read and written without a lock. The value itself is atomic, sure, but on processors with weak memory ordering it's possible for a reader to see the value change before it sees the associated message written into the buffer array. Fix by introducing a spinlock that's used just to read and write maxMsgNum. (We could do this with less overhead if we recognized a concept of "memory access barrier"; is it worth introducing such a thing? At the moment probably not --- I can't measure any clear slowdown from adding the spinlock, so this solution is probably fine.) Per buildfarm results.
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: http://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. Changes between all PostgreSQL releases are recorded in the file HISTORY. 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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.