From 77acab75dfe2e4741c25c0cf550266caef1eebd2 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 28 Apr 2010 16:54:16 +0000
Subject: Modify ShmemInitStruct and ShmemInitHash to throw errors internally,
 rather than returning NULL for some-but-not-all failures as they used to.
 Remove now-redundant tests for NULL from call sites.

We had to do something about this because many call sites were failing to
check for NULL; and changing it like this seems a lot more useful and
mistake-proof than adding checks to the call sites without them.
---
 src/backend/replication/walreceiverfuncs.c | 20 ++++++++------------
 src/backend/replication/walsender.c        | 27 +++++++++++----------------
 2 files changed, 19 insertions(+), 28 deletions(-)

(limited to 'src/backend/replication')

diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index be305790fd..78ee7fb9f7 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/replication/walreceiverfuncs.c,v 1.4 2010/02/26 02:00:57 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/replication/walreceiverfuncs.c,v 1.5 2010/04/28 16:54:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,17 +58,13 @@ WalRcvShmemInit(void)
 	WalRcv = (WalRcvData *)
 		ShmemInitStruct("Wal Receiver Ctl", WalRcvShmemSize(), &found);
 
-	if (WalRcv == NULL)
-		ereport(FATAL,
-				(errcode(ERRCODE_OUT_OF_MEMORY),
-				 errmsg("not enough shared memory for walreceiver")));
-	if (found)
-		return;					/* already initialized */
-
-	/* Initialize the data structures */
-	MemSet(WalRcv, 0, WalRcvShmemSize());
-	WalRcv->walRcvState = WALRCV_STOPPED;
-	SpinLockInit(&WalRcv->mutex);
+	if (!found)
+	{
+		/* First time through, so initialize */
+		MemSet(WalRcv, 0, WalRcvShmemSize());
+		WalRcv->walRcvState = WALRCV_STOPPED;
+		SpinLockInit(&WalRcv->mutex);
+	}
 }
 
 /* Is walreceiver in progress (or starting up)? */
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 6c41844b5f..07f2b23c91 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -30,7 +30,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.18 2010/04/28 16:10:42 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/replication/walsender.c,v 1.19 2010/04/28 16:54:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -268,8 +268,7 @@ WalSndHandshake(void)
 						if (wal_level == WAL_LEVEL_MINIMAL)
 							ereport(FATAL,
 									(errcode(ERRCODE_CANNOT_CONNECT_NOW),
-									 errmsg("standby connections not allowed because wal_level='minimal'")));
-
+									 errmsg("standby connections not allowed because wal_level=\"minimal\"")));
 
 						/* Send a CopyOutResponse message, and start streaming */
 						pq_beginmessage(&buf, 'H');
@@ -838,21 +837,17 @@ WalSndShmemInit(void)
 	WalSndCtl = (WalSndCtlData *)
 		ShmemInitStruct("Wal Sender Ctl", WalSndShmemSize(), &found);
 
-	if (WalSndCtl == NULL)
-		ereport(FATAL,
-				(errcode(ERRCODE_OUT_OF_MEMORY),
-				 errmsg("not enough shared memory for walsender")));
-	if (found)
-		return;					/* already initialized */
-
-	/* Initialize the data structures */
-	MemSet(WalSndCtl, 0, WalSndShmemSize());
-
-	for (i = 0; i < max_wal_senders; i++)
+	if (!found)
 	{
-		WalSnd	   *walsnd = &WalSndCtl->walsnds[i];
+		/* First time through, so initialize */
+		MemSet(WalSndCtl, 0, WalSndShmemSize());
+
+		for (i = 0; i < max_wal_senders; i++)
+		{
+			WalSnd	   *walsnd = &WalSndCtl->walsnds[i];
 
-		SpinLockInit(&walsnd->mutex);
+			SpinLockInit(&walsnd->mutex);
+		}
 	}
 }
 
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