0fd38e1370
The logical decoding patchset introduced PROC_IN_LOGICAL_DECODING flag PGXACT flag, that allows such backends to be skipped when computing the xmin horizon/snapshots. That's fine and sensible for walsenders streaming out logical changes, but not at all fine for SQL backends doing logical decoding. If the latter set that flag any change they have performed outside of logical decoding will not be regarded as visible - which e.g. can lead to that change being vacuumed away. Note that not setting the flag for SQL backends isn't particularly bothersome - the SQL backend doesn't do streaming, so it only runs for a limited amount of time. Per buildfarm member 'tick' and Alvaro. Backpatch to 9.4, where logical decoding was introduced.
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/.