0da096d78e
We shouldn't be doing non-trivial work in signal handlers in general, and in this case the handler could reach unsafe code and corrupt state. It also clobbered its own "reason" code. Move all recovery conflict decision logic into the next CHECK_FOR_INTERRUPTS(), and have the signal handler just set flags and the latch, following the standard pattern. Since there are several different "reasons", use a separate flag for each. With this refactoring, the recovery conflict system no longer piggy-backs on top of the regular query cancelation mechanism, but instead raises an error directly if it decides that is necessary. It still needs to respect QueryCancelHoldoffCount, because otherwise the FEBE protocol might get out of sync (see commit 2b3a8b20c2d). This fixes one class of intermittent failure in the new 031_recovery_conflict.pl test added by commit 9f8a050f, though the buggy coding is much older. Failures outside contrived testing seem to be very rare (or perhaps incorrectly attributed) in the field, based on lack of reports. No back-patch for now due to complexity and release schedule. We have the option to back-patch into 16 later, as 16 has prerequisite commit bea3d7e. Reviewed-by: Andres Freund <andres@anarazel.de> (earlier version) Reviewed-by: Michael Paquier <michael@paquier.xyz> (earlier version) Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier version) Tested-by: Christoph Berg <myon@debian.org> Discussion: https://postgr.es/m/CA%2BhUKGK3PGKwcKqzoosamn36YW-fsuTdOPPF1i_rtEO%3DnEYKSg%40mail.gmail.com Discussion: https://postgr.es/m/CALj2ACVr8au2J_9D88UfRCi0JdWhyQDDxAcSVav0B0irx9nXEg%40mail.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/.