cluster_rel() receives the OID of the relation to process, which it opens and locks; but then its subroutine copy_table_data() also receives the relation OID and opens it by itself. This is a bit wasteful. It's better to have cluster_rel() receive the relation already open, and pass it down to its subroutines as necessary; then cluster_rel closes the rel before returning. This simplifies things. But a better motivation to make this change is that a future command to do logical-decoding-based "concurrent VACUUM FULL" will need to release all locks on the relation (and possibly on the clustering index) at some point. Since it makes little sense to keep the relation reference without the lock, the cluster_rel() function will also close it (and the index). With this arrangement, neither the function nor its subroutines need open extra references, which, again, makes things simpler. Author: Antonin Houska <ah@cybertec.at> Discussion: https://postgr.es/m/82651.1720540558@antos
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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.