Back-patch bgworker API changes to 9.3.

robertmhaas · robertmhaas · commit 026bc46da33a · 2013-07-22T15:41:44.000-04:00
Commit 7f7485a made these changes in master; per discussion, backport the API changes (but not the functional changes), so that people don't get used to the 9.3 API only to see it get broken in the next release. There are already some people coding to the original 9.3 API, and this will cause minor breakage, but there will be even more if we wait until next year to roll out these changes.
diff --git a/contrib/worker_spi/worker_spi.c b/contrib/worker_spi/worker_spi.c
@@ -154,10 +154,17 @@ initialize_worker_spi(worktable *table)
 }
 
 static void
-worker_spi_main(void *main_arg)
+worker_spi_main(Datum main_arg)
 {
-	worktable  *table = (worktable *) main_arg;
+	int			index = DatumGetInt32(main_arg);
+	worktable  *table;
 	StringInfoData buf;
+	char		name[20];
+
+	table = palloc(sizeof(worktable));
+	sprintf(name, "schema%d", index);
+	table->schema = pstrdup(name);
+	table->name = pstrdup("counted");
 
 	/* Establish signal handlers before unblocking signals. */
 	pqsignal(SIGHUP, worker_spi_sighup);
@@ -296,9 +303,7 @@ void
 _PG_init(void)
 {
 	BackgroundWorker worker;
-	worktable  *table;
 	unsigned int i;
-	char		name[20];
 
 	/* get the configuration */
 	DefineCustomIntVariable("worker_spi.naptime",
@@ -338,14 +343,8 @@ _PG_init(void)
 	 */
 	for (i = 1; i <= worker_spi_total_workers; i++)
 	{
-		sprintf(name, "worker %d", i);
-		worker.bgw_name = pstrdup(name);
-
-		table = palloc(sizeof(worktable));
-		sprintf(name, "schema%d", i);
-		table->schema = pstrdup(name);
-		table->name = pstrdup("counted");
-		worker.bgw_main_arg = (void *) table;
+		snprintf(worker.bgw_name, BGW_MAXLEN, "worker %d", i);
+		worker.bgw_main_arg = Int32GetDatum(i);
 
 		RegisterBackgroundWorker(&worker);
 	}
diff --git a/doc/src/sgml/bgworker.sgml b/doc/src/sgml/bgworker.sgml
@@ -40,12 +40,12 @@
 typedef void (*bgworker_main_type)(void *main_arg);
 typedef struct BackgroundWorker
 {
-    char       *bgw_name;
+    char        bgw_name[BGW_MAXLEN];
     int         bgw_flags;
     BgWorkerStartTime bgw_start_time;
     int         bgw_restart_time;       /* in seconds, or BGW_NEVER_RESTART */
-    bgworker_main_type  bgw_main;
-    void       *bgw_main_arg;
+    bgworker_main_type bgw_main;
+    Datum       bgw_main_arg;
 } BackgroundWorker;
 </programlisting>
   </para>
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
@@ -5247,9 +5247,6 @@ RegisterBackgroundWorker(BackgroundWorker *worker)
 	}
 
 	rw->rw_worker = *worker;
-	rw->rw_worker.bgw_name = ((char *) rw) + sizeof(RegisteredBgWorker);
-	strlcpy(rw->rw_worker.bgw_name, worker->bgw_name, namelen + 1);
-
 	rw->rw_backend = NULL;
 	rw->rw_pid = 0;
 	rw->rw_child_slot = 0;
diff --git a/src/include/postmaster/bgworker.h b/src/include/postmaster/bgworker.h
@@ -52,7 +52,7 @@
 #define BGWORKER_BACKEND_DATABASE_CONNECTION		0x0002
 
 
-typedef void (*bgworker_main_type) (void *main_arg);
+typedef void (*bgworker_main_type) (Datum main_arg);
 
 /*
  * Points in time at which a bgworker can request to be started
@@ -66,15 +66,16 @@ typedef enum
 
 #define BGW_DEFAULT_RESTART_INTERVAL	60
 #define BGW_NEVER_RESTART				-1
+#define BGW_MAXLEN						64
 
 typedef struct BackgroundWorker
 {
-	char	   *bgw_name;
+	char	    bgw_name[BGW_MAXLEN];
 	int			bgw_flags;
 	BgWorkerStartTime bgw_start_time;
 	int			bgw_restart_time;		/* in seconds, or BGW_NEVER_RESTART */
 	bgworker_main_type bgw_main;
-	void	   *bgw_main_arg;
+	Datum		bgw_main_arg;
 } BackgroundWorker;
 
 /* Register a new bgworker */

Original file line number	Diff line number	Diff line change
`@@ -5247,9 +5247,6 @@ RegisterBackgroundWorker(BackgroundWorker *worker)`
`5247`	`5247`	`}`
`5248`	`5248`
`5249`	`5249`	`rw->rw_worker = *worker;`
`5250`		`- rw->rw_worker.bgw_name = ((char *) rw) + sizeof(RegisteredBgWorker);`
`5251`		`- strlcpy(rw->rw_worker.bgw_name, worker->bgw_name, namelen + 1);`
`5252`		`-`
`5253`	`5250`	`rw->rw_backend = NULL;`
`5254`	`5251`	`rw->rw_pid = 0;`
`5255`	`5252`	`rw->rw_child_slot = 0;`