9a56dc3389
1. Don't ignore query cancel interrupts. Instead, if the user asks to cancel the query after we've already committed it, but before it's on the standby, just emit a warning and let the COMMIT finish. 2. Don't ignore die interrupts (pg_terminate_backend or fast shutdown). Instead, emit a warning message and close the connection without acknowledging the commit. Other backends will still see the effect of the commit, but there's no getting around that; it's too late to abort at this point, and ignoring die interrupts altogether doesn't seem like a good idea. 3. If synchronous_standby_names becomes empty, wake up all backends waiting for synchronous replication to complete. Without this, someone attempting to shut synchronous replication off could easily wedge the entire system instead. 4. Avoid depending on the assumption that if a walsender updates MyProc->syncRepState, we'll see the change even if we read it without holding the lock. The window for this appears to be quite narrow (and probably doesn't exist at all on machines with strong memory ordering) but protecting against it is practically free, so do that. 5. Remove useless state SYNC_REP_MUST_DISCONNECT, which isn't needed and doesn't actually do anything. There's still some further work needed here to make the behavior of fast shutdown plausible, but that looks complex, so I'm leaving it for a separate commit. Review by Fujii Masao.
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/.