Ensure that values stored within arrays are not toasted, per

discussion on pghackers a few days ago.

diff --git a/src/backend/utils/adt/arrayfuncs.c b/src/backend/utils/adt/arrayfuncs.c
index d9a210592c51dbe4cfa17a19cb2854af5175c3a0..b0855b7740a372b90b966295d925c97352d1ac4c 100644 (file)
--- a/src/backend/utils/adt/arrayfuncs.c
+++ b/src/backend/utils/adt/arrayfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.63 2000/07/23 01:35:58 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.64 2000/07/27 03:50:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,6 +33,12 @@
  *       <dim_lower>   - lower boundary of each dimension
  *       <actual data> - whatever is the stored data
  * The actual data starts on a MAXALIGN boundary.
+ *
+ * NOTE: it is important that array elements of toastable datatypes NOT be
+ * toasted, since the tupletoaster won't know they are there.  (We could
+ * support compressed toasted items; only out-of-line items are dangerous.
+ * However, it seems preferable to store such items uncompressed and allow
+ * the toaster to compress the whole array as one input.)
  */
 
 
@@ -459,6 +465,8 @@ ReadArrayStr(char *arrayStr,
                {
                        if (values[i] != (Datum) 0)
                        {
+                               /* let's just make sure data is not toasted */
+                               values[i] = PointerGetDatum(PG_DETOAST_DATUM(values[i]));
                                if (typalign == 'd')
                                        *nbytes += MAXALIGN(VARSIZE(DatumGetPointer(values[i])));
                                else
@@ -485,6 +493,10 @@ ReadArrayStr(char *arrayStr,
  * typbyval, typlen, typalign: info about element datatype
  * freedata: if TRUE and element type is pass-by-ref, pfree data values
  * referenced by Datums after copying them.
+ *
+ * If the input data is of varlena type, the caller must have ensured that
+ * the values are not toasted.  (Doing it here doesn't work since the 
+ * caller has already allocated space for the array...)
  *----------
  */
 static void
@@ -961,6 +973,10 @@ array_set(ArrayType *array,
                return newarray;
        }
 
+       /* make sure item to be inserted is not toasted */
+       if (elmlen < 0)
+               dataValue = PointerGetDatum(PG_DETOAST_DATUM(dataValue));
+
        /* detoast input if necessary */
        array = DatumGetArrayTypeP(PointerGetDatum(array));
 
@@ -1120,6 +1136,8 @@ array_set_slice(ArrayType *array,
        array = DatumGetArrayTypeP(PointerGetDatum(array));
        srcArray = DatumGetArrayTypeP(PointerGetDatum(srcArray));
 
+       /* note: we assume srcArray contains no toasted elements */
+
        ndim = ARR_NDIM(array);
        if (ndim != nSubscripts || ndim <= 0 || ndim > MAXDIM)
                elog(ERROR, "Invalid array subscripts");
@@ -1368,12 +1386,14 @@ array_map(FunctionCallInfo fcinfo, Oid inpType, Oid retType)
                if (fcinfo->isnull)
                        elog(ERROR, "array_map: cannot handle NULL in array");
 
-               /* Update total result size */
-               if (typbyval)
+               /* Ensure data is not toasted, and update total result size */
+               if (typbyval || typlen > 0)
                        nbytes += typlen;
                else
-                       nbytes += ((typlen > 0) ? typlen :
-                                          INTALIGN(VARSIZE(DatumGetPointer(values[i]))));
+               {
+                       values[i] = PointerGetDatum(PG_DETOAST_DATUM(values[i]));
+                       nbytes += INTALIGN(VARSIZE(DatumGetPointer(values[i])));
+               }
        }
 
        /* Allocate and initialize the result array */
@@ -1420,10 +1440,13 @@ construct_array(Datum *elems, int nelems,
        }
        else
        {
-               /* varlena type */
+               /* varlena type ... make sure it is untoasted */
                nbytes = 0;
                for (i = 0; i < nelems; i++)
+               {
+                       elems[i] = PointerGetDatum(PG_DETOAST_DATUM(elems[i]));
                        nbytes += INTALIGN(VARSIZE(DatumGetPointer(elems[i])));
+               }
        }
 
        /* Allocate and initialize 1-D result array */