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.

4 files changed, 7 insertions, 13 deletions

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 6e6436d1528..7b684291a33 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: miscadmin.h,v 1.69 2000/11/04 12:43:24 petere Exp $
+ * $Id: miscadmin.h,v 1.70 2000/11/12 20:51:52 tgl Exp $
  *
  * NOTES
  *	  some of the information in this file will be moved to
@@ -55,7 +55,6 @@ extern char OutputFileName[];
  * done in storage/backendid.h for now.
  *
  * extern BackendId    MyBackendId;
- * extern BackendTag   MyBackendTag;
  */
 extern bool MyDatabaseIdIsInitialized;
 extern Oid	MyDatabaseId;
diff --git a/src/include/storage/backendid.h b/src/include/storage/backendid.h
index ad7b1f079f5..22c52012f07 100644
--- a/src/include/storage/backendid.h
+++ b/src/include/storage/backendid.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: backendid.h,v 1.7 2000/01/26 05:58:32 momjian Exp $
+ * $Id: backendid.h,v 1.8 2000/11/12 20:51:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,16 +18,11 @@
  *		-cim 8/17/90
  * ----------------
  */
-typedef int16 BackendId;		/* unique currently active backend
+typedef int BackendId;			/* unique currently active backend
 								 * identifier */
 
 #define InvalidBackendId		(-1)
 
-typedef int32 BackendTag;		/* unique backend identifier */
-
-#define InvalidBackendTag		(-1)
-
 extern BackendId MyBackendId;	/* backend id of this backend */
-extern BackendTag MyBackendTag; /* backend tag of this backend */
 
 #endif	 /* BACKENDID_H */
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h
index 32b51b5f43b..4c80f760faa 100644
--- a/src/include/storage/sinval.h
+++ b/src/include/storage/sinval.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: sinval.h,v 1.14 2000/01/26 05:58:33 momjian Exp $
+ * $Id: sinval.h,v 1.15 2000/11/12 20:51:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,7 +27,7 @@ extern void RegisterSharedInvalid(int cacheId, Index hashIndex,
 extern void InvalidateSharedInvalid(void (*invalFunction) (),
 												void (*resetFunction) ());
 
-extern bool DatabaseHasActiveBackends(Oid databaseId);
+extern bool DatabaseHasActiveBackends(Oid databaseId, bool ignoreMyself);
 extern bool TransactionIdIsInProgress(TransactionId xid);
 extern void GetXmaxRecent(TransactionId *XmaxRecent);
 
diff --git a/src/include/storage/sinvaladt.h b/src/include/storage/sinvaladt.h
index 30fe1e06daf..b9704d34e4d 100644
--- a/src/include/storage/sinvaladt.h
+++ b/src/include/storage/sinvaladt.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: sinvaladt.h,v 1.22 2000/06/15 03:33:00 momjian Exp $
+ * $Id: sinvaladt.h,v 1.23 2000/11/12 20:51:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -77,7 +77,6 @@ typedef struct ProcState
 	/* nextMsgNum is -1 in an inactive ProcState array entry. */
 	int			nextMsgNum;		/* next message number to read, or -1 */
 	bool		resetState;		/* true, if backend has to reset its state */
-	int			tag;			/* backend tag received from postmaster */
 	SHMEM_OFFSET procStruct;	/* location of backend's PROC struct */
 } ProcState;
 
@@ -90,6 +89,7 @@ typedef struct SISeg
 	 */
 	int			minMsgNum;		/* oldest message still needed */
 	int			maxMsgNum;		/* next message number to be assigned */
+	int			lastBackend;	/* index of last active procState entry, +1 */
 	int			maxBackends;	/* size of procState array */
 
 	/*