diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 3c23f43a59f19bfb70bf75e9c104f1ee51933669..8a624614e8d196b0dc9730c9fa31f35c3f8ccfe8 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.211 2004/06/25 17:20:21 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.212 2004/07/02 18:59:20 joe Exp $
 PostgreSQL documentation
 -->
 
@@ -7232,6 +7232,10 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
     <primary>pg_get_serial_sequence</primary>
    </indexterm>
 
+   <indexterm zone="functions-misc">
+    <primary>pg_tablespace_databases</primary>
+   </indexterm>
+
   <para>
    <xref linkend="functions-misc-catalog-table"> lists functions that
    extract information from the system catalogs.
@@ -7325,6 +7329,11 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        <entry>get name of the sequence that a serial or bigserial column
        uses</entry>
       </row>
+      <row>
+       <entry><literal><function>pg_tablespace_databases</function>(<parameter>tablespace_oid</parameter>)</literal></entry>
+       <entry><type>setof oid</type></entry>
+       <entry>get set of database oids that have objects in the tablespace</entry>
+      </row>
      </tbody>
     </tgroup>
    </table>
@@ -7362,6 +7371,16 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
    NULL is returned if the column does not have a sequence attached.
   </para>
 
+  <para>
+  <function>pg_tablespace_databases</function> allows usage examination of a
+  tablespace. It will return a set of database oids, that have objects
+  stored in the tablespace. If this function returns any row, the
+  tablespace is assumed not to be empty and cannot be dropped. To
+  display the actual objects populating the tablespace, you will need
+  to connect to the databases returned by 
+  <function>pg_tablespace_databases</function> to query pg_class.
+  </para>
+
    <indexterm zone="functions-misc">
     <primary>obj_description</primary>
    </indexterm>
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 847985456f7007ea2f91064646c3318fefeafd7e..875fb1cae8a8a57dc0fcad827cc9f187b9c5ba52 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -45,7 +45,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.4 2004/06/25 21:55:53 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.5 2004/07/02 18:59:22 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -315,7 +315,7 @@ CreateTableSpace(CreateTableSpaceStmt *stmt)
 	/*
 	 * All seems well, create the symlink
 	 */
-	linkloc = (char *) palloc(strlen(DataDir) + 16 + 10 + 1);
+	linkloc = (char *) palloc(strlen(DataDir) + 11 + 10 + 1);
 	sprintf(linkloc, "%s/pg_tblspc/%u", DataDir, tablespaceoid);
 
 	if (symlink(location, linkloc) < 0)
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 8ab6953cb02c151148a9fabc449b0b9c157128b9..0cc315c6205e2d8717c93716e702146e65646ecc 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.34 2004/06/02 21:29:29 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.35 2004/07/02 18:59:22 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,11 +16,16 @@
 
 #include <sys/file.h>
 #include <signal.h>
+#include <dirent.h>
 
 #include "commands/dbcommands.h"
 #include "miscadmin.h"
 #include "storage/sinval.h"
+#include "storage/fd.h"
 #include "utils/builtins.h"
+#include "funcapi.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_tablespace.h"
 
 
 /*
@@ -103,3 +108,97 @@ pg_cancel_backend(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGINT));
 }
+
+
+typedef struct 
+{
+	char *location;
+	DIR *dirdesc;
+} ts_db_fctx;
+
+Datum pg_tablespace_databases(PG_FUNCTION_ARGS)
+{
+	FuncCallContext *funcctx;
+	struct dirent *de;
+	ts_db_fctx *fctx;
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		MemoryContext oldcontext;
+		Oid tablespaceOid=PG_GETARG_OID(0);
+
+		funcctx=SRF_FIRSTCALL_INIT();
+		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+		fctx = palloc(sizeof(ts_db_fctx));
+
+		/*
+		 * size = path length + tablespace dirname length
+		 *        + 2 dir sep chars + oid + terminator
+		 */
+		fctx->location = (char*) palloc(strlen(DataDir) + 11 + 10 + 1);
+		if (tablespaceOid == GLOBALTABLESPACE_OID)
+		{
+			fctx->dirdesc = NULL;
+			ereport(NOTICE,
+					(errcode(ERRCODE_WARNING),
+					 errmsg("global tablespace never has databases.")));
+		}
+		else
+		{
+			if (tablespaceOid == DEFAULTTABLESPACE_OID)
+				sprintf(fctx->location, "%s/base", DataDir);
+			else
+				sprintf(fctx->location, "%s/pg_tblspc/%u", DataDir,
+														   tablespaceOid);
+		
+			fctx->dirdesc = AllocateDir(fctx->location);
+
+			if (!fctx->dirdesc)  /* not a tablespace */
+				ereport(NOTICE,
+						(errcode(ERRCODE_WARNING),
+						 errmsg("%d is no tablespace oid.", tablespaceOid)));
+		}
+		funcctx->user_fctx = fctx;
+		MemoryContextSwitchTo(oldcontext);
+	}
+
+	funcctx=SRF_PERCALL_SETUP();
+	fctx = (ts_db_fctx*) funcctx->user_fctx;
+
+	if (!fctx->dirdesc)  /* not a tablespace */
+		SRF_RETURN_DONE(funcctx);
+
+	while ((de = readdir(fctx->dirdesc)) != NULL)
+	{
+		char *subdir;
+		DIR *dirdesc;
+
+		Oid datOid = atol(de->d_name);
+		if (!datOid)
+			continue;
+
+		/* size = path length + dir sep char + file name + terminator */
+		subdir = palloc(strlen(fctx->location) + 1 + strlen(de->d_name) + 1);
+		sprintf(subdir, "%s/%s", fctx->location, de->d_name);
+		dirdesc = AllocateDir(subdir);
+		if (dirdesc)
+		{
+			while ((de = readdir(dirdesc)) != 0)
+			{
+				if (strcmp(de->d_name, ".") && strcmp(de->d_name, ".."))
+					break;
+			}
+			pfree(subdir);
+			FreeDir(dirdesc);
+
+			if (!de)   /* database subdir is empty; don't report tablespace as used */
+				continue;
+		}
+
+		SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(datOid));
+	}
+
+	FreeDir(fctx->dirdesc);
+	SRF_RETURN_DONE(funcctx);
+}
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index b6f98778628edc1fb971e5533fa89d2ba78b65d9..98e554e759992b7892526c4cc9c7c60cb7939a02 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.241 2004/07/01 00:51:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.242 2004/07/02 18:59:24 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200406261
+#define CATALOG_VERSION_NO	200407021
 
 #endif
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 489fa9ca9baa5a5c250c65b681bab154364fb4bc..8d2485c168d5393379ae9f3c8bf283b5cea38f30 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.339 2004/06/25 17:20:28 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.340 2004/07/02 18:59:24 joe Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -3595,6 +3595,9 @@ DESCR("bitwise-and bit aggregate");
 DATA(insert OID = 2243 ( bit_or						   PGNSP PGUID 12 t f f f i 1 1560 "1560" _null_ aggregate_dummy - _null_));
 DESCR("bitwise-or bit aggregate");
 
+DATA(insert OID = 2554(  pg_tablespace_databases       PGNSP PGUID 12 f f t t s 1 26 "26" _null_ pg_tablespace_databases - _null_));
+DESCR("returns database oids in a tablespace");
+
 /*
  * Symbolic values for provolatile column: these indicate whether the result
  * of a function is dependent *only* on the values of its explicit arguments,
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 99974cdec126497952244e71e125c0b3f720576d..c18ad551e485a988f883aa52f583196a6b586493 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.244 2004/06/25 17:20:29 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.245 2004/07/02 18:59:25 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -356,6 +356,7 @@ extern Datum nonnullvalue(PG_FUNCTION_ARGS);
 extern Datum current_database(PG_FUNCTION_ARGS);
 extern Datum pg_terminate_backend(PG_FUNCTION_ARGS);
 extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);
+extern Datum pg_tablespace_databases(PG_FUNCTION_ARGS);
 
 /* not_in.c */
 extern Datum int4notin(PG_FUNCTION_ARGS);