Tablespaces. Alternate database locations are dead, long live tablespaces.

There are various things left to do: contrib dbsize and oid2name modules
need work, and so does the documentation.  Also someone should think about
COMMENT ON TABLESPACE and maybe RENAME TABLESPACE.  Also initlocation is
dead, it just doesn't know it yet.

Gavin Sherry and Tom Lane.

1 files changed, 18 insertions, 20 deletions

diff --git a/src/backend/utils/misc/database.c b/src/backend/utils/misc/database.c
index 37844a03a94..1eeb5357040 100644
--- a/src/backend/utils/misc/database.c
+++ b/src/backend/utils/misc/database.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/database.c,v 1.60 2004/01/22 20:57:39 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/database.c,v 1.61 2004/06/18 06:13:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,6 +21,7 @@
 #include "catalog/catname.h"
 #include "catalog/catalog.h"
 #include "catalog/pg_database.h"
+#include "catalog/pg_tablespace.h"
 #include "miscadmin.h"
 #include "utils/syscache.h"
 
@@ -29,12 +30,13 @@ static bool PhonyHeapTupleSatisfiesNow(HeapTupleHeader tuple);
 
 
 /* --------------------------------
- *	GetRawDatabaseInfo() -- Find the OID and path of the database.
+ *	GetRawDatabaseInfo() -- Find the OID and tablespace of the database.
  *
- *		The database's oid forms half of the unique key for the system
- *		caches and lock tables.  We therefore want it initialized before
- *		we open any relations, since opening relations puts things in the
- *		cache.	To get around this problem, this code opens and scans the
+ *		We need both the OID and the default tablespace in order to find
+ *		the database's system catalogs.  Moreover the database's OID forms
+ *		half of the unique key for the system caches and lock tables, so
+ *		we must have it before we can use any of the cache mechanisms.
+ *		To get around these problems, this code opens and scans the
  *		pg_database relation by hand.
  *
  *		This code knows way more than it should about the layout of
@@ -43,19 +45,21 @@ static bool PhonyHeapTupleSatisfiesNow(HeapTupleHeader tuple);
  * --------------------------------
  */
 void
-GetRawDatabaseInfo(const char *name, Oid *db_id, char *path)
+GetRawDatabaseInfo(const char *name, Oid *db_id, Oid *db_tablespace)
 {
 	int			dbfd;
 	int			nbytes;
-	int			pathlen;
 	HeapTupleData tup;
+	Form_pg_database tup_db;
 	Page		pg;
 	char	   *dbfname;
-	Form_pg_database tup_db;
 	RelFileNode rnode;
 
-	rnode.tblNode = 0;
+	/* hard-wired path to pg_database */
+	rnode.spcNode = GLOBALTABLESPACE_OID;
+	rnode.dbNode = 0;
 	rnode.relNode = RelOid_pg_database;
+
 	dbfname = relpath(rnode);
 
 	if ((dbfd = open(dbfname, O_RDONLY | PG_BINARY, 0)) < 0)
@@ -121,7 +125,7 @@ GetRawDatabaseInfo(const char *name, Oid *db_id, char *path)
 			 * committed and dead tuples to be marked with correct states.
 			 *
 			 * XXX wouldn't it be better to let new backends read the
-			 * database OID from a flat file, handled the same way we
+			 * database info from a flat file, handled the same way we
 			 * handle the password relation?
 			 */
 			if (!PhonyHeapTupleSatisfiesNow(tup.t_data))
@@ -134,15 +138,9 @@ GetRawDatabaseInfo(const char *name, Oid *db_id, char *path)
 
 			if (strcmp(name, NameStr(tup_db->datname)) == 0)
 			{
-				/* Found it; extract the OID and the database path. */
+				/* Found it; extract the db's OID and tablespace. */
 				*db_id = HeapTupleGetOid(&tup);
-				pathlen = VARSIZE(&(tup_db->datpath)) - VARHDRSZ;
-				if (pathlen < 0)
-					pathlen = 0;	/* pure paranoia */
-				if (pathlen >= MAXPGPATH)
-					pathlen = MAXPGPATH - 1;	/* more paranoia */
-				strncpy(path, VARDATA(&(tup_db->datpath)), pathlen);
-				path[pathlen] = '\0';
+				*db_tablespace = tup_db->dattablespace;
 				goto done;
 			}
 		}
@@ -150,7 +148,7 @@ GetRawDatabaseInfo(const char *name, Oid *db_id, char *path)
 
 	/* failed to find it... */
 	*db_id = InvalidOid;
-	*path = '\0';
+	*db_tablespace = InvalidOid;
 
 done:
 	close(dbfd);