Keep track of the last active slot in the shared ProcState array, so

that search loops only have to scan that far and not through all maxBackends
entries.  This eliminates a performance penalty for setting maxBackends
much higher than the average number of active backends.  Also, eliminate
no-longer-used 'backend tag' concept.  Remove setting of environment
variables at backend start (except for CYR_RECODE), since none of them
are being examined by the backend any longer.

1 files changed, 69 insertions, 115 deletions

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index e2a1dec6fb8..e50c0ee4d0e 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.181 2000/11/09 11:25:59 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.182 2000/11/12 20:51:51 tgl Exp $
  *
  * NOTES
  *
@@ -107,55 +107,45 @@ typedef struct bkend
 Port	   *MyBackendPort = NULL;
 
 /* list of active backends.  For garbage collection only now. */
-
 static Dllist *BackendList;
 
 /* list of ports associated with still open, but incomplete connections */
 static Dllist *PortList;
 
+/* The socket number we are listening for connections on */
 int PostPortName;
 
- /*
-  * This is a boolean indicating that there is at least one backend that
-  * is accessing the current shared memory and semaphores. Between the
-  * time that we start up, or throw away shared memory segments and start
-  * over, and the time we generate the next backend (because we received a
-  * connection request), it is false. Other times, it is true.
-  */
+/*
+ * This is a sequence number that indicates how many times we've had to
+ * throw away the shared memory and start over because we doubted its
+ * integrity.	It starts off at zero and is incremented every time we
+ * start over.  We use this to ensure that we use a new IPC shared memory
+ * key for the new shared memory segment in case the old segment isn't
+ * entirely gone yet.
+ *
+ * The sequence actually cycles back to 0 after 9, so pathologically there
+ * could be an IPC failure if 10 sets of backends are all stuck and won't
+ * release IPC resources.
+ */
 static short shmem_seq = 0;
 
- /*
-  * This is a sequence number that indicates how many times we've had to
-  * throw away the shared memory and start over because we doubted its
-  * integrity.	It starts off at zero and is incremented every time we
-  * start over.  We use this to ensure that we use a new IPC shared memory
-  * key for the new shared memory segment in case the old segment isn't
-  * entirely gone yet.
-  *
-  * The sequence actually cycles back to 0 after 9, so pathologically there
-  * could be an IPC failure if 10 sets of backends are all stuck and won't
-  * release IPC resources.
-  */
-
+/*
+ * This is the base IPC shared memory key.  Other keys are generated by
+ * adding to this.
+ */
 static IpcMemoryKey ipc_key;
 
- /*
-  * This is the base IPC shared memory key.  Other keys are generated by
-  * adding to this.
-  */
-
+/*
+ * MaxBackends is the actual limit on the number of backends we will
+ * start. The default is established by configure, but it can be
+ * readjusted from 1..MAXBACKENDS with the postmaster -N switch. Note
+ * that a larger MaxBackends value will increase the size of the shared
+ * memory area as well as cause the postmaster to grab more kernel
+ * semaphores, even if you never actually use that many backends.
+ */
 int	MaxBackends = DEF_MAXBACKENDS;
 
- /*
-  * MaxBackends is the actual limit on the number of backends we will
-  * start. The default is established by configure, but it can be
-  * readjusted from 1..MAXBACKENDS with the postmaster -N switch. Note
-  * that a larger MaxBackends value will increase the size of the shared
-  * memory area as well as cause the postmaster to grab more kernel
-  * semaphores, even if you never actually use that many backends.
-  */
 
-static int	NextBackendTag = INT_MAX;	/* XXX why count down not up? */
 static char *progname = (char *) NULL;
 static char **real_argv;
 static int	real_argc;
@@ -587,6 +577,22 @@ PostmasterMain(int argc, char *argv[])
 		exit(1);
 	}
 
+	if (DebugLvl > 2)
+	{
+		extern char **environ;
+		char	  **p;
+
+		fprintf(stderr, "%s: PostmasterMain: initial environ dump:\n",
+				progname);
+		fprintf(stderr, "-----------------------------------------\n");
+		for (p = environ; *p; ++p)
+			fprintf(stderr, "\t%s\n", *p);
+		fprintf(stderr, "-----------------------------------------\n");
+	}
+
+	/*
+	 * Establish input sockets.
+	 */
 #ifdef USE_SSL
 	if (EnableSSL && !NetServer)
 	{
@@ -600,7 +606,8 @@ PostmasterMain(int argc, char *argv[])
 
 	if (NetServer)
 	{
-		status = StreamServerPort(AF_INET, (unsigned short)PostPortName, &ServerSock_INET);
+		status = StreamServerPort(AF_INET, (unsigned short) PostPortName,
+								  &ServerSock_INET);
 		if (status != STATUS_OK)
 		{
 			fprintf(stderr, "%s: cannot create INET stream port\n",
@@ -610,7 +617,8 @@ PostmasterMain(int argc, char *argv[])
 	}
 
 #ifdef HAVE_UNIX_SOCKETS
-	status = StreamServerPort(AF_UNIX, (unsigned short)PostPortName, &ServerSock_UNIX);
+	status = StreamServerPort(AF_UNIX, (unsigned short) PostPortName,
+							  &ServerSock_UNIX);
 	if (status != STATUS_OK)
 	{
 		fprintf(stderr, "%s: cannot create UNIX stream port\n",
@@ -618,10 +626,11 @@ PostmasterMain(int argc, char *argv[])
 		ExitPostmaster(1);
 	}
 #endif
+
 	/* set up shared memory and semaphores */
 	reset_shared(PostPortName);
 
-	/* Init XLOG pathes */
+	/* Init XLOG paths */
 	snprintf(XLogDir, MAXPGPATH, "%s/pg_xlog", DataDir);
 	snprintf(ControlFilePath, MAXPGPATH, "%s/global/pg_control", DataDir);
 
@@ -1706,43 +1715,7 @@ static int
 BackendStartup(Port *port)
 {
 	Backend    *bn;				/* for backend cleanup */
-	int			pid,
-				i;
-
-#ifdef CYR_RECODE
-#define NR_ENVIRONMENT_VBL 5
-	char		ChTable[80];
-
-#else
-#define NR_ENVIRONMENT_VBL 4
-#endif
-
-	static char envEntry[NR_ENVIRONMENT_VBL][2 * ARGV_SIZE];
-
-	for (i = 0; i < NR_ENVIRONMENT_VBL; ++i)
-		MemSet(envEntry[i], 0, 2 * ARGV_SIZE);
-
-	/*
-	 * Set up the necessary environment variables for the backend This
-	 * should really be some sort of message....
-	 */
-	sprintf(envEntry[0], "POSTPORT=%d", PostPortName);
-	putenv(envEntry[0]);
-	sprintf(envEntry[1], "POSTID=%d", NextBackendTag);
-	putenv(envEntry[1]);
-	sprintf(envEntry[2], "PGDATA=%s", DataDir);
-	putenv(envEntry[2]);
-	sprintf(envEntry[3], "IPC_KEY=%d", ipc_key);
-	putenv(envEntry[3]);
-
-#ifdef CYR_RECODE
-	GetCharSetByHost(ChTable, port->raddr.in.sin_addr.s_addr, DataDir);
-	if (*ChTable != '\0')
-	{
-		sprintf(envEntry[4], "PG_RECODETABLE=%s", ChTable);
-		putenv(envEntry[4]);
-	}
-#endif
+	int			pid;
 
 	/*
 	 * Compute the cancel key that will be assigned to this backend. The
@@ -1751,19 +1724,6 @@ BackendStartup(Port *port)
 	 */
 	MyCancelKey = PostmasterRandom();
 
-	if (DebugLvl > 2)
-	{
-		char	  **p;
-		extern char **environ;
-
-		fprintf(stderr, "%s: BackendStartup: environ dump:\n",
-				progname);
-		fprintf(stderr, "-----------------------------------------\n");
-		for (p = environ; *p; ++p)
-			fprintf(stderr, "\t%s\n", *p);
-		fprintf(stderr, "-----------------------------------------\n");
-	}
-
 	/*
 	 * Flush stdio channels just before fork, to avoid double-output
 	 * problems. Ideally we'd use fflush(NULL) here, but there are still a
@@ -1779,12 +1739,30 @@ BackendStartup(Port *port)
 	/* Specific beos actions before backend startup */
 	beos_before_backend_startup();
 #endif
+
 	if ((pid = fork()) == 0)
 	{							/* child */
 #ifdef __BEOS__
-		/* Specific beos backend stratup actions */
+		/* Specific beos backend startup actions */
 		beos_backend_startup();
 #endif
+
+#ifdef CYR_RECODE
+		{
+			/* Save charset for this host while we still have client addr */
+			char		ChTable[80];
+			static char cyrEnvironment[100];
+
+			GetCharSetByHost(ChTable, port->raddr.in.sin_addr.s_addr, DataDir);
+			if (*ChTable != '\0')
+			{
+				snprintf(cyrEnvironment, sizeof(cyrEnvironment),
+						 "PG_RECODETABLE=%s", ChTable);
+				putenv(cyrEnvironment);
+			}
+		}
+#endif
+
 		if (DoBackend(port))
 		{
 			fprintf(stderr, "%s child[%d]: BackendStartup: backend startup failed\n",
@@ -1799,7 +1777,7 @@ BackendStartup(Port *port)
 	if (pid < 0)
 	{
 #ifdef __BEOS__
-		/* Specific beos backend stratup actions */
+		/* Specific beos backend startup actions */
 		beos_backend_startup_failed();
 #endif
 		fprintf(stderr, "%s: BackendStartup: fork failed: %s\n",
@@ -1812,14 +1790,6 @@ BackendStartup(Port *port)
 				progname, pid, port->user, port->database,
 				port->sock);
 
-	/* Generate a new backend tag for every backend we start */
-
-	/*
-	 * XXX theoretically this could wrap around, if you have the patience
-	 * to start 2^31 backends ...
-	 */
-	NextBackendTag -= 1;
-
 	/*
 	 * Everything's been successful, it's safe to add this backend to our
 	 * list of backends.
@@ -2179,21 +2149,7 @@ static pid_t
 SSDataBase(int xlop)
 {
 	pid_t		pid;
-	int			i;
 	Backend	   *bn;
-	static char ssEntry[4][2 * ARGV_SIZE];
-
-	for (i = 0; i < 4; ++i)
-		MemSet(ssEntry[i], 0, 2 * ARGV_SIZE);
-
-	sprintf(ssEntry[0], "POSTPORT=%d", PostPortName);
-	putenv(ssEntry[0]);
-	sprintf(ssEntry[1], "POSTID=%d", NextBackendTag);
-	putenv(ssEntry[1]);
-	sprintf(ssEntry[2], "PGDATA=%s", DataDir);
-	putenv(ssEntry[2]);
-	sprintf(ssEntry[3], "IPC_KEY=%d", ipc_key);
-	putenv(ssEntry[3]);
 
 	fflush(stdout);
 	fflush(stderr);
@@ -2258,8 +2214,6 @@ SSDataBase(int xlop)
 		ExitPostmaster(1);
 	}
 
-	NextBackendTag -= 1;
-
 	if (xlop != BS_XLOG_CHECKPOINT)
 		return(pid);