Arrange for the postmaster (and standalone backends, initdb, etc) to

chdir into PGDATA and subsequently use relative paths instead of absolute
paths to access all files under PGDATA.  This seems to give a small
performance improvement, and it should make the system more robust
against naive DBAs doing things like moving a database directory that
has a live postmaster in it.  Per recent discussion.

1 files changed, 13 insertions, 7 deletions

diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 1c9725d6298..a4fb354a4c9 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/init/globals.c,v 1.95 2004/12/31 22:01:40 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/init/globals.c,v 1.96 2005/07/04 04:51:50 tgl Exp $
  *
  * NOTES
  *	  Globals used all over the place should be declared here and not
@@ -36,13 +36,14 @@ int			MyProcPid;
 struct Port *MyProcPort;
 long		MyCancelKey;
 
+/*
+ * DataDir is the absolute path to the top level of the PGDATA directory tree.
+ * Except during early startup, this is also the server's working directory;
+ * most code therefore can simply use relative paths and not reference DataDir
+ * explicitly.
+ */
 char	   *DataDir = NULL;
 
- /*
-  * The PGDATA directory user says to use, or defaults to via environment
-  * variable.  NULL if no option given and no environment variable set
-  */
-
 char		OutputFileName[MAXPGPATH];	/* debugging output file */
 
 char		my_exec_path[MAXPGPATH];	/* full path to my executable */
@@ -56,11 +57,16 @@ char		postgres_exec_path[MAXPGPATH];		/* full path to backend */
 
 BackendId	MyBackendId = InvalidBackendId;
 
-char	   *DatabasePath = NULL;
 Oid			MyDatabaseId = InvalidOid;
 
 Oid			MyDatabaseTableSpace = InvalidOid;
 
+/*
+ * DatabasePath is the path (relative to DataDir) of my database's
+ * primary directory, ie, its directory in the default tablespace.
+ */
+char	   *DatabasePath = NULL;
+
 pid_t		PostmasterPid = 0;
 
 /*