Autovacuum launchers perform no WAL IO reads, but pgstat_tracks_io_op() was tracking them as an allowed combination for the "init" and "normal" contexts. This caused the "read", "read_bytes" and "read_time" attributes of pg_stat_io to show zeros for the autovacuum launcher rather than NULL. NULL means that a combination of IO object, IO context and IO operation has no meaning for a backend type. Zero is the same as telling that a combination is relevant, and that WAL reads are possible in an autovacuum launcher, but it is not relevant. Copy-pasto introduced in a051e71e28a1. Author: Ranier Vilela <ranier.vf@gmail.com> Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com> Discussion: https://postgr.es/m/CAEudQAopEMAPiUqE7BvDV+x2fUPmKmb9RrsaoDR+hhQzLKg4PQ@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.
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/.