Thanks for the patches! I have only reviewed the v8-0001-Parallel-index-autovacuum.patch so far and have a few comments from my initial pass.
1/ Please run pgindent. 2/ Documentation is missing. There may be more, but here are the places I found that likely need updates for the new behavior, reloptions, GUC, etc. Including docs in the patch early would help clarify expected behavior. https://www.postgresql.org/docs/current/routine-vacuuming.html#VACUUM-BASICS https://www.postgresql.org/docs/current/routine-vacuuming.html#AUTOVACUUM https://www.postgresql.org/docs/current/runtime-config-autovacuum.html https://www.postgresql.org/docs/current/sql-createtable.html https://www.postgresql.org/docs/current/sql-altertable.html https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-MAX-WORKER-PROCESSES https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-MAX-PARALLEL-MAINTENANCE-WORKERS One thing I am unclear on is the interaction between max_worker_processes, max_parallel_workers, and max_parallel_maintenance_workers. For example, does the following change mean that manual VACUUM PARALLEL is no longer capped by max_parallel_maintenance_workers? @@ -597,8 +614,8 @@ parallel_vacuum_compute_workers(Relation *indrels, int nindexes, int nrequested, parallel_workers = (nrequested > 0) ? Min(nrequested, nindexes_parallel) : nindexes_parallel; - /* Cap by max_parallel_maintenance_workers */ - parallel_workers = Min(parallel_workers, max_parallel_maintenance_workers); + /* Cap by GUC variable */ + parallel_workers = Min(parallel_workers, max_parallel_workers); 3/ Shouldn't this be "max_parallel_workers" instead of "bgworkers pool" ? + "autovacuum_parallel_workers", + "Maximum number of parallel autovacuum workers that can be taken from bgworkers pool for processing this table. " 4/ The comment "When parallel autovacuum worker die" suggests an abnormal exit. "Terminates" seems clearer, since this applies to both normal and abnormal exits. instead of: + * When parallel autovacuum worker die, how about this: * When parallel autovacuum worker terminates, 5/ Any reason AutoVacuumReleaseParallelWorkers cannot be called before DestroyParallelContext? + nlaunched_workers = pvs->pcxt->nworkers_launched; /* remember this value */ DestroyParallelContext(pvs->pcxt); + + /* Release all launched (i.e. reserved) parallel autovacuum workers. */ + if (AmAutoVacuumWorkerProcess()) + AutoVacuumReleaseParallelWorkers(nlaunched_workers); 6/ Also, would it be cleaner to move AmAutoVacuumWorkerProcess() inside AutoVacuumReleaseParallelWorkers()? if (!AmAutoVacuumWorkerProcess()) return; 7/ It looks like the psql tab completion for autovacuum_parallel_workers is missing: test=# alter table t set (autovacuum_ autovacuum_analyze_scale_factor autovacuum_analyze_threshold autovacuum_enabled autovacuum_freeze_max_age autovacuum_freeze_min_age autovacuum_freeze_table_age autovacuum_multixact_freeze_max_age autovacuum_multixact_freeze_min_age autovacuum_multixact_freeze_table_age autovacuum_vacuum_cost_delay autovacuum_vacuum_cost_limit autovacuum_vacuum_insert_scale_factor autovacuum_vacuum_insert_threshold autovacuum_vacuum_max_threshold autovacuum_vacuum_scale_factor autovacuum_vacuum_threshold -- Sami Imseih Amazon Web Services (AWS)
