From b8917f6b5f159ecc6c73957c7806a14f256b1608 Mon Sep 17 00:00:00 2001 From: Kuntal Ghosh Date: Mon, 10 Apr 2017 15:43:17 +0530 Subject: [PATCH 2/2] Add GUC for max_parallel_workers upper limit --- src/backend/postmaster/bgworker.c | 10 ++++++++++ src/backend/utils/misc/guc.c | 4 ++-- src/include/postmaster/bgworker.h | 7 +++++++ 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c index 59b13fc..d386a3a 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -941,6 +941,16 @@ RegisterDynamicBackgroundWorker(BackgroundWorker *worker, * postmaster must not take locks; a memory barrier wouldn't guarantee * anything useful. */ + + /* + * For a parallel worker, the absolute difference between parallal worker + * register count and terminate count must be less than maximum parallel + * worker count limit. + */ + Assert(!parallel || abs((int)(BackgroundWorkerData->parallel_register_count - + BackgroundWorkerData->parallel_terminate_count)) <= + MAX_PARALLEL_WORKER_LIMIT); + if (parallel && (BackgroundWorkerData->parallel_register_count - BackgroundWorkerData->parallel_terminate_count) >= max_parallel_workers) diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index a57b175..3081cfb 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2689,7 +2689,7 @@ static struct config_int ConfigureNamesInt[] = NULL }, &max_parallel_workers_per_gather, - 2, 0, 1024, + 2, 0, MAX_PARALLEL_WORKER_LIMIT, NULL, NULL, NULL }, @@ -2699,7 +2699,7 @@ static struct config_int ConfigureNamesInt[] = NULL }, &max_parallel_workers, - 8, 0, 1024, + 8, 0, MAX_PARALLEL_WORKER_LIMIT, NULL, NULL, NULL }, diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h index 51a5978..7f55f4b 100644 --- a/src/include/postmaster/bgworker.h +++ b/src/include/postmaster/bgworker.h @@ -41,6 +41,13 @@ #ifndef BGWORKER_H #define BGWORKER_H +/* GUC options */ + +/* + * Maximum possible value of parallel workers. + */ +#define MAX_PARALLEL_WORKER_LIMIT 1024 + /*--------------------------------------------------------------------- * External module API. *--------------------------------------------------------------------- -- 1.8.3.1