Fix monitor extension for new Postgres 15 shared memory hooks. (#922)

* Fix monitor extension for new Postgres 15 shared memory hooks.

* Per review, we didn't introduce PG_VERSION_15 in this project.

Dockerfile

@@ -53,7 +53,7 @@ RUN apt-get update \
 	&& rm -rf /var/lib/apt/lists/*
 
 RUN curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
-RUN echo "deb http://apt.postgresql.org/pub/repos/apt buster-pgdg main" > /etc/apt/sources.list.d/pgdg.list
+RUN echo "deb http://apt.postgresql.org/pub/repos/apt buster-pgdg main ${PGVERSION}" > /etc/apt/sources.list.d/pgdg.list
 
 # bypass initdb of a "main" cluster
 RUN echo 'create_main_cluster = false' | sudo tee -a /etc/postgresql-common/createcluster.conf
@@ -132,7 +132,7 @@ RUN apt-get update \
 	&& rm -rf /var/lib/apt/lists/*
 
 RUN curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
-RUN echo "deb http://apt.postgresql.org/pub/repos/apt buster-pgdg main" > /etc/apt/sources.list.d/pgdg.list
+RUN echo "deb http://apt.postgresql.org/pub/repos/apt buster-pgdg main ${PGVERSION}" > /etc/apt/sources.list.d/pgdg.list
 
 # bypass initdb of a "main" cluster
 RUN echo 'create_main_cluster = false' | sudo tee -a /etc/postgresql-common/createcluster.conf

Makefile

@@ -174,6 +174,9 @@ build-test-pg13:
 build-test-pg14:
 	docker build --build-arg PGVERSION=14 --target test -t $(TEST_CONTAINER_NAME):pg14 .
 
+build-test-pg15:
+	docker build --build-arg PGVERSION=15 --target test -t $(TEST_CONTAINER_NAME):pg15 .
+
 run-test: build-test-pg$(PGVERSION)
 	docker run					                \
 		--name $(TEST_CONTAINER_NAME)		    \
@@ -197,6 +200,9 @@ build-pg13: build-test-pg13
 build-pg14: build-test-pg14
 	docker build --build-arg PGVERSION=14 $(DOCKER_BUILD_OPTS) -t $(CONTAINER_NAME):pg14 .
 
+build-pg15: build-test-pg15
+	docker build --build-arg PGVERSION=15 $(DOCKER_BUILD_OPTS) -t $(CONTAINER_NAME):pg15 .
+
 build: build-pg10 build-pg11 build-pg12 build-pg13 build-pg14 ;
 
 build-check:

src/monitor/health_check.h

@@ -52,6 +52,7 @@ extern int HealthCheckTimeout;
 extern int HealthCheckMaxRetries;
 extern int HealthCheckRetryDelay;
 
+extern size_t HealthCheckWorkerShmemSize(void);
 
 extern void InitializeHealthCheckWorker(void);
 extern void HealthCheckWorkerMain(Datum arg);

src/monitor/health_check_worker.c

@@ -139,7 +139,6 @@ static int CompareTimes(struct timeval *leftTime, struct timeval *rightTime);
 static int SubtractTimes(struct timeval base, struct timeval subtract);
 static struct timeval AddTimeMillis(struct timeval base, uint32 additionalMs);
 static void LatchWait(long timeoutMs);
-static size_t HealthCheckWorkerShmemSize(void);
 static void HealthCheckWorkerShmemInit(void);
 
 
@@ -196,10 +195,13 @@ pg_auto_failover_monitor_sighup(SIGNAL_ARGS)
 void
 InitializeHealthCheckWorker(void)
 {
+	/* on PG 15, we use shmem_request_hook_type */
+#if PG_VERSION_NUM < 150000
 	if (!IsUnderPostmaster)
 	{
 		RequestAddinShmemSpace(HealthCheckWorkerShmemSize());
 	}
+#endif
 
 	prev_shmem_startup_hook = shmem_startup_hook;
 	shmem_startup_hook = HealthCheckWorkerShmemInit;
@@ -1086,7 +1088,7 @@ AddTimeMillis(struct timeval base, uint32 additionalMs)
 /*
  * HealthCheckWorkerShmemSize computes how much shared memory is required.
  */
-static size_t
+size_t
 HealthCheckWorkerShmemSize(void)
 {
 	Size size = 0;

src/monitor/pg_auto_failover.c

@@ -38,6 +38,12 @@
 ProcessUtility_hook_type PreviousProcessUtility_hook = NULL;
 
 
+#if PG_VERSION_NUM >= 150000
+static shmem_request_hook_type prev_shmem_request_hook = NULL;
+static void pgautofailover_shmem_request(void);
+#endif
+
+
 void _PG_init(void);
 static void StartMonitorNode(void);
 
@@ -77,10 +83,35 @@ _PG_init(void)
 						 "configuration variable in postgresql.conf.")));
 	}
 
+#if PG_VERSION_NUM >= 150000
+	prev_shmem_request_hook = shmem_request_hook;
+	shmem_request_hook = pgautofailover_shmem_request;
+#endif
+
 	StartMonitorNode();
 }
 
 
+#if PG_VERSION_NUM >= 150000
+
+/*
+ * Requests any additional shared memory required for pg_auto_failover health
+ * check worker.
+ */
+static void
+pgautofailover_shmem_request(void)
+{
+	if (prev_shmem_request_hook)
+	{
+		prev_shmem_request_hook();
+	}
+
+	RequestAddinShmemSpace(HealthCheckWorkerShmemSize());
+}
+
+
+#endif
+
 /*
  * StartMonitor register GUCs for monitor mode and starts the
  * health check worker.