v2-0001-Support-worker_spi-to-execute-the-function-dynamical.patch

From 02ef0d8daddd43305842987a6aeac6732b2415a9 Mon Sep 17 00:00:00 2001
From: Masahiro Ikeda <masahiro.ikeda.us@hco.ntt.co.jp>
Date: Thu, 20 Jul 2023 10:34:50 +0900
Subject: [PATCH] Support worker_spi to execute the function dynamically.

Currently, the database name to connect is initialized only
when process_shared_preload_libraries_in_progress is true.
It means that worker_spi_launch() fails if shared_preload_libraries
is empty because the database to connect is NULL.

The patch changes that the database name is always initilized
when called _PG_init(). We can call worker_spi_launch() and
launch SPI workers dynamically.

It also changes the configuration for the test because we don't
need "shared_preload_libraries = worker_spi" anymore, and
background workers launched in initialized phase always have
failed because the "contrib_regression" database is not created yet.
---
 src/test/modules/worker_spi/Makefile     |  4 ++--
 src/test/modules/worker_spi/dynamic.conf |  3 +--
 src/test/modules/worker_spi/worker_spi.c | 27 ++++++++++++++----------
 3 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/src/test/modules/worker_spi/Makefile b/src/test/modules/worker_spi/Makefile
index cbf9b2e37f..c2d32d9b72 100644
--- a/src/test/modules/worker_spi/Makefile
+++ b/src/test/modules/worker_spi/Makefile
@@ -8,10 +8,10 @@ PGFILEDESC = "worker_spi - background worker example"
 
 REGRESS = worker_spi
 
-# enable our module in shared_preload_libraries for dynamic bgworkers
 REGRESS_OPTS = --temp-config $(top_srcdir)/src/test/modules/worker_spi/dynamic.conf
 
-# Disable installcheck to ensure we cover dynamic bgworkers.
+# Disable because these tests require "worker_spi.database = contrib_regression",
+# which typical installcheck users do not have (e.g. buildfarm clients).
 NO_INSTALLCHECK = 1
 
 ifdef USE_PGXS
diff --git a/src/test/modules/worker_spi/dynamic.conf b/src/test/modules/worker_spi/dynamic.conf
index bfe015f664..d9fd463a53 100644
--- a/src/test/modules/worker_spi/dynamic.conf
+++ b/src/test/modules/worker_spi/dynamic.conf
@@ -1,2 +1 @@
-shared_preload_libraries = worker_spi
-worker_spi.database = contrib_regression
+worker_spi.database = contrib_regression
\ No newline at end of file
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 7227cfaa45..f691fbec9f 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -282,7 +282,12 @@ _PG_init(void)
 {
 	BackgroundWorker worker;
 
-	/* get the configuration */
+	/* Get the configuration */
+
+	/*
+	 * These GUCs are defined even if this library is not loaded with
+	 * shared_preload_libraries, for worker_spi_launch().
+	 */
 	DefineCustomIntVariable("worker_spi.naptime",
 							"Duration between each check (in seconds).",
 							NULL,
@@ -296,6 +301,15 @@ _PG_init(void)
 							NULL,
 							NULL);
 
+	DefineCustomStringVariable("worker_spi.database",
+							   "Database to connect to.",
+							   NULL,
+							   &worker_spi_database,
+							   "postgres",
+							   PGC_SIGHUP,
+							   0,
+							   NULL, NULL, NULL);
+
 	if (!process_shared_preload_libraries_in_progress)
 		return;
 
@@ -312,18 +326,9 @@ _PG_init(void)
 							NULL,
 							NULL);
 
-	DefineCustomStringVariable("worker_spi.database",
-							   "Database to connect to.",
-							   NULL,
-							   &worker_spi_database,
-							   "postgres",
-							   PGC_POSTMASTER,
-							   0,
-							   NULL, NULL, NULL);
-
 	MarkGUCPrefixReserved("worker_spi");
 
-	/* set up common data for all our workers */
+	/* Set up common data for all our workers */
 	memset(&worker, 0, sizeof(worker));
 	worker.bgw_flags = BGWORKER_SHMEM_ACCESS |
 		BGWORKER_BACKEND_DATABASE_CONNECTION;
-- 
2.25.1