fc415edf8c
This commit adds two callbacks in pgstats to have a better control of the flush timing of pgstat_report_stat(), whose operation depends on the three PGSTAT_*_INTERVAL variables: - have_fixed_pending_cb(), to check if a stats kind has any pending data waiting for a flush. This is used as a fast path if there are no pending statistics to flush, and this check is done for fixed-numbered statistics only if there are no variable-numbered statistics to flush. A flush will need to happen if at least one callback reports any pending data. - flush_fixed_cb(), to do the actual flush. These callbacks are currently used by the SLRU, WAL and IO statistics, generalizing the concept for all stats kinds (builtin and custom). The SLRU and IO stats relied each on one global variable to determine whether a flush should happen; these are now local to pgstat_slru.c and pgstat_io.c, cleaning up a bit how the pending flush states are tracked in pgstat.c. pgstat_flush_io() and pgstat_flush_wal() are still required, but we do not need to check their return result anymore. Reviewed-by: Bertrand Drouvot, Kyotaro Horiguchi Discussion: https://postgr.es/m/ZtaVO0N-aTwiAk3w@paquier.xyz
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.
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