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Up until now, we've held this lock when performing a checkpoint or restartpoint, but commit 076a055acf3c55314de267c62b03191586d79cf6 back in 2004 and commit 7e48b77b1cebb9a43f9fdd6b17128a0ba36132f9 from 2009, taken together, have removed all need for this. In the present code, there's only ever one process entitled to attempt a checkpoint: either the checkpointer, during normal operation, or the postmaster, during single-user operation. So, we don't need the lock. One possible concern in making this change is that it means that a substantial amount of code where HOLD_INTERRUPTS() was previously in effect due to the preceding LWLockAcquire() will now be running without that. This could mean that ProcessInterrupts() gets called in places from which it didn't before. However, this seems unlikely to do very much, because the checkpointer doesn't have any signal mapped to die(), so it's not clear how, for example, ProcDiePending = true could happen in the first place. Similarly with ClientConnectionLost and recovery conflicts. Also, if there are any such problems, we might want to fix them rather than reverting this, since running lots of code with interrupt handling suspended is generally bad. Patch by me, per an inquiry by Amul Sul. Review by Tom Lane and Michael Paquier. Discussion: http://postgr.es/m/CAAJ_b97XnBBfYeSREDJorFsyoD1sHgqnNuCi=02mNQBUMnA=FA@mail.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/.