Change on-disk representation of NUMERIC datatype so that the sign_dscale

word comes before the weight instead of after.  This will allow future
binary-compatible extension of the representation to support compact formats,
as discussed on pgsql-hackers around 2007/06/18.  The reason to do it now is
that we've already pretty well broken any chance of simple in-place upgrade
from 8.2 to 8.3, but it's possible that 8.3 to 8.4 (or whenever we get around
to squeezing NUMERIC) could otherwise be data-compatible.

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index d00770a..9776bc1 100644 (file)
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.428 2007/09/25 20:03:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.429 2007/09/25 22:21:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*                                                     yyyymmddN */
-#define CATALOG_VERSION_NO     200709241
+#define CATALOG_VERSION_NO     200709251
 
 #endif

diff --git a/src/include/utils/numeric.h b/src/include/utils/numeric.h
index cffba1e..e142515 100644 (file)
--- a/src/include/utils/numeric.h
+++ b/src/include/utils/numeric.h
@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1998-2007, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/include/utils/numeric.h,v 1.24 2007/02/27 23:48:10 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/numeric.h,v 1.25 2007/09/25 22:21:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,14 +63,14 @@
 typedef struct NumericData
 {
        int32           vl_len_;                /* varlena header (do not touch directly!) */
-       int16           n_weight;               /* Weight of 1st digit  */
        uint16          n_sign_dscale;  /* Sign + display scale */
+       int16           n_weight;               /* Weight of 1st digit  */
        char            n_data[1];              /* Digits (really array of NumericDigit) */
 } NumericData;
 
 typedef NumericData *Numeric;
 
-#define NUMERIC_HDRSZ  (VARHDRSZ + sizeof(int16) + sizeof(uint16))
+#define NUMERIC_HDRSZ  (VARHDRSZ + sizeof(uint16) + sizeof(int16))
 
 
 /*