First phase of plan-invalidation project: create a plan cache management

module and teach PREPARE and protocol-level prepared statements to use it.
In service of this, rearrange utility-statement processing so that parse
analysis does not assume table schemas can't change before execution for
utility statements (necessary because we don't attempt to re-acquire locks
for utility statements when reusing a stored plan).  This requires some
refactoring of the ProcessUtility API, but it ends up cleaner anyway,
for instance we can get rid of the QueryContext global.

Still to do: fix up SPI and related code to use the plan cache; I'm tempted to
try to make SQL functions use it too.  Also, there are at least some aspects
of system state that we want to ensure remain the same during a replan as in
the original processing; search_path certainly ought to behave that way for
instance, and perhaps there are others.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
index fd304b66ad5..f046f397e8c 100644
--- a/src/include/utils/memutils.h
+++ b/src/include/utils/memutils.h
@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/memutils.h,v 1.61 2007/01/05 22:19:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/memutils.h,v 1.62 2007/03/13 00:33:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -75,8 +75,7 @@ extern DLLIMPORT MemoryContext MessageContext;
 extern DLLIMPORT MemoryContext TopTransactionContext;
 extern DLLIMPORT MemoryContext CurTransactionContext;
 
-/* These two are transient links to contexts owned by other objects: */
-extern DLLIMPORT MemoryContext QueryContext;
+/* This is a transient link to the active portal's memory context: */
 extern DLLIMPORT MemoryContext PortalContext;