adapt shared_ispell for upcoming PostgreSQL 15

ashutosh108 · Anton Voloshin · commit 64b5868f0e83 · 2022-07-20T12:35:27.000+03:00
1. Only call RequestAddinShmemSpace and RequestNamedLWLockTranche from within
our implementation of shmem_request_hook (as required after commit 4f2400cb3
in PostgreSQL 15).

2. While we are here, remove _PG_fini, as it is now officially dead
after commit ab02d702e in PostgreSQL 15.
diff --git a/src/shared_ispell.c b/src/shared_ispell.c
@@ -66,12 +66,11 @@
 PG_MODULE_MAGIC;
 
 void _PG_init(void);
-void _PG_fini(void);
 
 /* Memory for dictionaries in kbytes */
 static int max_ispell_mem_size_kb;
 
-/* Saved hook values in case of unload */
+/* Saved hook value for proper chaining */
 static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
 
 /* These are used to allocate data within shared segment */
@@ -97,6 +96,11 @@ max_ispell_mem_size()
 	return (Size) max_ispell_mem_size_kb * 1024L;
 }
 
+#if (PG_VERSION_NUM >= 150000)
+static shmem_request_hook_type prev_shmem_request_hook = NULL;
+static void shared_ispell_shmem_request(void);
+#endif
+
 /*
  * Module load callback
  */
@@ -127,33 +131,33 @@ _PG_init(void)
 
 	EmitWarningsOnPlaceholders("shared_ispell");
 
-	/*
-	 * Request additional shared resources.  (These are no-ops if we're not in
-	 * the postmaster process.)  We'll allocate or attach to the shared
-	 * resources in ispell_shmem_startup().
-	 */
+#if PG_VERSION_NUM >= 150000
+	prev_shmem_request_hook = shmem_request_hook;
+	shmem_request_hook = shared_ispell_shmem_request;
+#else
 	RequestAddinShmemSpace(max_ispell_mem_size());
 
 #if PG_VERSION_NUM >= 90600
 	RequestNamedLWLockTranche("shared_ispell", 1);
 #else
 	RequestAddinLWLocks(1);
+#endif
 #endif
 
 	/* Install hooks. */
 	prev_shmem_startup_hook = shmem_startup_hook;
 	shmem_startup_hook = ispell_shmem_startup;
 }
 
-
-/*
- * Module unload callback
- */
-void
-_PG_fini(void)
+static void
+shared_ispell_shmem_request(void)
 {
-	/* Uninstall hooks. */
-	shmem_startup_hook = prev_shmem_startup_hook;
+	if (prev_shmem_request_hook)
+		prev_shmem_request_hook();
+
+	RequestAddinShmemSpace(max_ispell_mem_size());
+
+	RequestNamedLWLockTranche("shared_ispell", 1);
 }
 
 /*
