eda4ef8151
pg_stat_get_snapshot_timestamp() returns the timestamp seen in the "global" stats file. Because pgstat_write_statsfiles() writes per-DB stats files before the global file (or at least before renaming it into place), there is a window where the test backend can see all the stats updates that wait_for_stats() was checking for (all of which come from the per-DB file) but also see the same global stats file it had seen at the start of the test script. This results in a failure in only the "snapshot_newer" query, as reported by a couple of buildfarm members recently. I suspect that this ought to be back-patched. Commit 4e37b3e15 has evidently increased the probability of this window getting hit, but it's not apparent why it could not have been hit before. I'll refrain for the moment though.
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. 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/.