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Formerly, Unix builds of pg_dump/pg_restore would trap SIGINT and similar signals and set a flag that was tested in various data-transfer loops. This was prone to errors of omission (cf commit 3c8aa6654); and even if the client-side response was prompt, we did nothing that would cause long-running SQL commands (e.g. CREATE INDEX) to terminate early. Also, the master process would effectively do nothing at all upon receipt of SIGINT; the only reason it seemed to work was that in typical scenarios the signal would also be delivered to the child processes. We should support termination when a signal is delivered only to the master process, though. Windows builds had no console interrupt handler, so they would just fall over immediately at control-C, again leaving long-running SQL commands to finish unmolested. To fix, remove the flag-checking approach altogether. Instead, allow the Unix signal handler to send a cancel request directly and then exit(1). In the master process, also have it forward the signal to the children. On Windows, add a console interrupt handler that behaves approximately the same. The main difference is that a single execution of the Windows handler can send all the cancel requests since all the info is available in one process, whereas on Unix each process sends a cancel only for its own database connection. In passing, fix an old problem that DisconnectDatabase tends to send a cancel request before exiting a parallel worker, even if nothing went wrong. This is at least a waste of cycles, and could lead to unexpected log messages, or maybe even data loss if it happened in pg_restore (though in the current code the problem seems to affect only pg_dump). The cause was that after a COPY step, pg_dump was leaving libpq in PGASYNC_BUSY state, causing PQtransactionStatus() to report PQTRANS_ACTIVE. That's normally harmless because the next PQexec() will silently clear the PGASYNC_BUSY state; but in a parallel worker we might exit without any additional SQL commands after a COPY step. So add an extra PQgetResult() call after a COPY to allow libpq to return to PGASYNC_IDLE state. This is a bug fix, IMO, so back-patch to 9.3 where parallel dump/restore were introduced. Thanks to Kyotaro Horiguchi for Windows testing and code suggestions. Original-Patch: <7005.1464657274@sss.pgh.pa.us> Discussion: <20160602.174941.256342236.horiguchi.kyotaro@lab.ntt.co.jp>
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/.