v1-0002-poc-test-parallel_tuple_queue_size.patch

From 455026b0f70eec8acf3565824c03a9e20588e9cc Mon Sep 17 00:00:00 2001
From: Dilip Kumar <dilipkumar@localhost.localdomain>
Date: Mon, 26 Jul 2021 20:18:48 +0530
Subject: [PATCH v1 2/2] poc-test-parallel_tuple_queue_size

---
 src/backend/executor/execParallel.c |  3 ++-
 src/backend/utils/misc/guc.c        | 10 ++++++++++
 src/include/storage/pg_shmem.h      |  1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c
index f8a4a40..f9dd5fc 100644
--- a/src/backend/executor/execParallel.c
+++ b/src/backend/executor/execParallel.c
@@ -51,6 +51,7 @@
 #include "utils/memutils.h"
 #include "utils/snapmgr.h"
 
+int			parallel_tuple_queue_size =	65536;
 /*
  * Magic numbers for parallel executor communication.  We use constants
  * greater than any 32-bit integer here so that values < 2^32 can be used
@@ -67,7 +68,7 @@
 #define PARALLEL_KEY_JIT_INSTRUMENTATION UINT64CONST(0xE000000000000009)
 #define PARALLEL_KEY_WAL_USAGE			UINT64CONST(0xE00000000000000A)
 
-#define PARALLEL_TUPLE_QUEUE_SIZE		65536
+#define PARALLEL_TUPLE_QUEUE_SIZE		parallel_tuple_queue_size * 1024L
 
 /*
  * Fixed-size random stuff that we need to pass to parallel workers.
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c339acf..4d5dca5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3346,6 +3346,16 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
+		{"parallel_tuple_queue_size", PGC_USERSET, RESOURCES_MEM,
+			gettext_noop("Sets the parallel tuple queue size."),
+			GUC_UNIT_KB
+		},
+		&parallel_tuple_queue_size,
+		64, 64, MAX_KILOBYTES,
+		NULL, NULL, NULL
+	},
+
+	{
 		{"autovacuum_work_mem", PGC_SIGHUP, RESOURCES_MEM,
 			gettext_noop("Sets the maximum memory to be used by each autovacuum worker process."),
 			NULL,
diff --git a/src/include/storage/pg_shmem.h b/src/include/storage/pg_shmem.h
index 059df1b..9182a0e 100644
--- a/src/include/storage/pg_shmem.h
+++ b/src/include/storage/pg_shmem.h
@@ -45,6 +45,7 @@ typedef struct PGShmemHeader	/* standard header for all Postgres shmem */
 extern int	shared_memory_type;
 extern int	huge_pages;
 extern int	huge_page_size;
+extern int	parallel_tuple_queue_size;
 
 /* Possible values for huge_pages */
 typedef enum
-- 
1.8.3.1