Back-port heap_deformtuple() into 7.4 branch; needed for planned fix for

CLUSTER failure after ALTER TABLE SET WITHOUT OIDS.

diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index dad99b0059d32656aeaaceb127b7fc8e0331f04d..cd4e853fa6468ca4e84291df93b6f666343b88af 100644 (file)
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.87 2003/09/25 06:57:56 petere Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.87.2.1 2005/02/06 20:15:32 tgl Exp $
  *
  * NOTES
  *       The old interface functions have been converted to macros
@@ -512,41 +512,6 @@ heap_copytuple_with_tuple(HeapTuple src, HeapTuple dest)
        memcpy((char *) dest->t_data, (char *) src->t_data, src->t_len);
 }
 
-#ifdef NOT_USED
-/* ----------------
- *             heap_deformtuple
- *
- *             the inverse of heap_formtuple (see below)
- * ----------------
- */
-void
-heap_deformtuple(HeapTuple tuple,
-                                TupleDesc tdesc,
-                                Datum *values,
-                                char *nulls)
-{
-       int                     i;
-       int                     natts;
-
-       Assert(HeapTupleIsValid(tuple));
-
-       natts = tuple->t_natts;
-       for (i = 0; i < natts; i++)
-       {
-               bool            isnull;
-
-               values[i] = heap_getattr(tuple,
-                                                                i + 1,
-                                                                tdesc,
-                                                                &isnull);
-               if (isnull)
-                       nulls[i] = 'n';
-               else
-                       nulls[i] = ' ';
-       }
-}
-#endif
-
 /* ----------------
  *             heap_formtuple
  *
@@ -712,6 +677,93 @@ heap_modifytuple(HeapTuple tuple,
        return newTuple;
 }
 
+/* ----------------
+ *             heap_deformtuple
+ *
+ *             Given a tuple, extract data into values/nulls arrays; this is
+ *             the inverse of heap_formtuple.
+ *
+ *             Storage for the values/nulls arrays is provided by the caller;
+ *             it should be sized according to tupleDesc->natts not tuple->t_natts.
+ *
+ *             Note that for pass-by-reference datatypes, the pointer placed
+ *             in the Datum will point into the given tuple.
+ *
+ *             When all or most of a tuple's fields need to be extracted,
+ *             this routine will be significantly quicker than a loop around
+ *             heap_getattr; the loop will become O(N^2) as soon as any
+ *             noncacheable attribute offsets are involved.
+ * ----------------
+ */
+void
+heap_deformtuple(HeapTuple tuple,
+                                TupleDesc tupleDesc,
+                                Datum *values,
+                                char *nulls)
+{
+       HeapTupleHeader tup = tuple->t_data;
+       Form_pg_attribute *att = tupleDesc->attrs;
+       int                     tdesc_natts = tupleDesc->natts;
+       int                     natts;                  /* number of atts to extract */
+       int                     attnum;
+       char       *tp;                         /* ptr to tuple data */
+       long            off;                    /* offset in tuple data */
+       bits8      *bp = tup->t_bits;           /* ptr to null bitmask in tuple */
+       bool            slow = false;   /* can we use/set attcacheoff? */
+
+       natts = tup->t_natts;
+
+       /*
+        * In inheritance situations, it is possible that the given tuple
+        * actually has more fields than the caller is expecting.  Don't run
+        * off the end of the caller's arrays.
+        */
+       natts = Min(natts, tdesc_natts);
+
+       tp = (char *) tup + tup->t_hoff;
+
+       off = 0;
+
+       for (attnum = 0; attnum < natts; attnum++)
+       {
+               if (!HeapTupleNoNulls(tuple) && att_isnull(attnum, bp))
+               {
+                       values[attnum] = (Datum) 0;
+                       nulls[attnum] = 'n';
+                       slow = true;            /* can't use attcacheoff anymore */
+                       continue;
+               }
+
+               nulls[attnum] = ' ';
+
+               if (!slow && att[attnum]->attcacheoff >= 0)
+                       off = att[attnum]->attcacheoff;
+               else
+               {
+                       off = att_align(off, att[attnum]->attalign);
+
+                       if (!slow)
+                               att[attnum]->attcacheoff = off;
+               }
+
+               values[attnum] = fetchatt(att[attnum], tp + off);
+
+               off = att_addlength(off, att[attnum]->attlen, tp + off);
+
+               if (att[attnum]->attlen <= 0)
+                       slow = true;            /* can't use attcacheoff anymore */
+       }
+
+       /*
+        * If tuple doesn't have all the atts indicated by tupleDesc, read the
+        * rest as null
+        */
+       for (; attnum < tdesc_natts; attnum++)
+       {
+               values[attnum] = (Datum) 0;
+               nulls[attnum] = 'n';
+       }
+}
 
 /* ----------------
  *             heap_freetuple

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index ed46894d3a59ce6c9254cd6a489d63cceb03b358..2df812ef0073743d1a0c876ff8762dc858d0dca8 100644 (file)
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: heapam.h,v 1.85 2003/10/01 21:30:52 tgl Exp $
+ * $Id: heapam.h,v 1.85.2.1 2005/02/06 20:15:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -192,6 +192,8 @@ extern HeapTuple heap_formtuple(TupleDesc tupleDescriptor,
                           Datum *value, char *nulls);
 extern HeapTuple heap_modifytuple(HeapTuple tuple,
                Relation relation, Datum *replValue, char *replNull, char *repl);
+extern void heap_deformtuple(HeapTuple tuple, TupleDesc tupleDesc,
+                                                        Datum *values, char *nulls);
 extern void heap_freetuple(HeapTuple tuple);
 extern HeapTuple heap_addheader(int natts, bool withoid, Size structlen, void *structure);