Tweak startup sequence so that running out of PROC array slots is

detected sooner in backend startup, and is treated as an expected error
(it gives 'Sorry, too many clients already' now).  This allows us not
to have to enforce the MaxBackends limit exactly in the postmaster.
Also, remove ProcRemove() and fold its functionality into ProcKill().
There's no good reason for a backend not to be responsible for removing
its PROC entry, and there are lots of good reasons for the postmaster
not to be touching shared-memory data structures.

1 files changed, 38 insertions, 30 deletions

diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index c3c3ad946ec..dedd9a8e765 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.86 2001/05/30 20:52:32 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.87 2001/06/16 22:58:16 tgl Exp $
  *
  *
  *-------------------------------------------------------------------------
@@ -148,13 +148,11 @@ ReverifyMyDatabase(const char *name)
 static void
 InitCommunication(void)
 {
-
 	/*
 	 * initialize shared memory and semaphores appropriately.
 	 */
 	if (!IsUnderPostmaster)		/* postmaster already did this */
 	{
-
 		/*
 		 * we're running a postgres backend by itself with no front end or
 		 * postmaster.	Create private "shmem" and semaphores.	Setting
@@ -168,11 +166,16 @@ InitCommunication(void)
 /*
  * Early initialization of a backend (either standalone or under postmaster).
  * This happens even before InitPostgres.
+ *
+ * If you're wondering why this is separate from InitPostgres at all:
+ * the critical distinction is that this stuff has to happen before we can
+ * run XLOG-related initialization, which is done before InitPostgres --- in
+ * fact, for cases such as checkpoint creation processes, InitPostgres may
+ * never be done at all.
  */
 void
 BaseInit(void)
 {
-
 	/*
 	 * Attach to shared memory and semaphores, and initialize our
 	 * input/output/debugging file descriptors.
@@ -184,8 +187,6 @@ BaseInit(void)
 	smgrinit();
 	InitBufferPoolAccess();
 	InitLocalBuffer();
-
-	EnablePortalManager();		/* memory for portal/transaction stuff */
 }
 
 
@@ -202,16 +203,18 @@ InitPostgres(const char *dbname, const char *username)
 {
 	bool		bootstrap = IsBootstrapProcessingMode();
 
-	SetDatabaseName(dbname);
-
 	/*
-	 * initialize the database id used for system caches and lock tables
+	 * Set up the global variables holding database name, id, and path.
+	 *
+	 * We take a shortcut in the bootstrap case, otherwise we have to look up
+	 * the db name in pg_database.
 	 */
+	SetDatabaseName(dbname);
+
 	if (bootstrap)
 	{
 		MyDatabaseId = TemplateDbOid;
 		SetDatabasePath(GetDatabasePath(MyDatabaseId));
-		LockDisable(true);
 	}
 	else
 	{
@@ -260,6 +263,28 @@ InitPostgres(const char *dbname, const char *username)
 	 */
 
 	/*
+	 * Set up my per-backend PROC struct in shared memory.  (We need to
+	 * know MyDatabaseId before we can do this, since it's entered into
+	 * the PROC struct.)
+	 */
+	InitProcess();
+
+	/*
+	 * Initialize my entry in the shared-invalidation manager's array of
+	 * per-backend data.  (Formerly this came before InitProcess, but now
+	 * it must happen after, because it uses MyProc.)  Once I have done
+	 * this, I am visible to other backends!
+	 *
+	 * Sets up MyBackendId, a unique backend identifier.
+	 */
+	MyBackendId = InvalidBackendId;
+
+	InitBackendSharedInvalidationState();
+
+	if (MyBackendId > MAXBACKENDS || MyBackendId <= 0)
+		elog(FATAL, "InitPostgres: bad backend id %d", MyBackendId);
+
+	/*
 	 * Initialize the transaction system and the relation descriptor
 	 * cache. Note we have to make certain the lock manager is off while
 	 * we do this.
@@ -282,26 +307,6 @@ InitPostgres(const char *dbname, const char *username)
 	LockDisable(false);
 
 	/*
-	 * Set up my per-backend PROC struct in shared memory.
-	 */
-	InitProcess();
-
-	/*
-	 * Initialize my entry in the shared-invalidation manager's array of
-	 * per-backend data.  (Formerly this came before InitProcess, but now
-	 * it must happen after, because it uses MyProc.)  Once I have done
-	 * this, I am visible to other backends!
-	 *
-	 * Sets up MyBackendId, a unique backend identifier.
-	 */
-	MyBackendId = InvalidBackendId;
-
-	InitBackendSharedInvalidationState();
-
-	if (MyBackendId > MAXBACKENDS || MyBackendId <= 0)
-		elog(FATAL, "cinit2: bad backend id %d", MyBackendId);
-
-	/*
 	 * Initialize the access methods. Does not touch files (?) - thomas
 	 * 1997-11-01
 	 */
@@ -315,6 +320,9 @@ InitPostgres(const char *dbname, const char *username)
 	 */
 	InitCatalogCache();
 
+	/* Initialize portal manager */
+	EnablePortalManager();
+
 	/*
 	 * Initialize the deferred trigger manager --- must happen before
 	 * first transaction start.