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Remove partial, broken support for NULL pointers when fetching attributes.
Previously, fastgetattr() and heap_getattr() tested their fourth argument against a null pointer, but any attempt to use them with a literal-NULL fourth argument evaluated to *(void *)0, resulting in a compiler error. Remove these NULL tests to avoid leading future readers of this code to believe that this has a chance of working. Also clean up related legacy code in nocachegetattr(), heap_getsysattr(), and nocache_index_getattr(). The new coding standard is that any code which calls a getattr-type function or macro which takes an isnull argument MUST pass a valid boolean pointer. Per discussion with Bruce Momjian, Tom Lane, Alvaro Herrera.
This commit is contained in:
Robert Haas
@ -50,7 +50,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.129 2010/01/02 16:57:33 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.130 2010/01/10 04:26:36 rhaas Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -323,8 +323,7 @@ heap_attisnull(HeapTuple tup, int attnum)
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Datum
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nocachegetattr(HeapTuple tuple,
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int attnum,
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TupleDesc tupleDesc,
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bool *isnull)
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TupleDesc tupleDesc)
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{
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HeapTupleHeader tup = tuple->t_data;
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Form_pg_attribute *att = tupleDesc->attrs;
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@ -333,8 +332,6 @@ nocachegetattr(HeapTuple tuple,
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bool slow = false; /* do we have to walk attrs? */
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int off; /* current offset within data */
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(void) isnull; /* not used */
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/* ----------------
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* Three cases:
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*
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@ -344,68 +341,32 @@ nocachegetattr(HeapTuple tuple,
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* ----------------
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*/
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#ifdef IN_MACRO
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/* This is handled in the macro */
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Assert(attnum > 0);
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if (isnull)
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*isnull = false;
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#endif
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attnum--;
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if (HeapTupleNoNulls(tuple))
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{
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#ifdef IN_MACRO
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/* This is handled in the macro */
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if (att[attnum]->attcacheoff >= 0)
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{
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return fetchatt(att[attnum],
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(char *) tup + tup->t_hoff +
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att[attnum]->attcacheoff);
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}
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#endif
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}
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else
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if (!HeapTupleNoNulls(tuple))
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{
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/*
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* there's a null somewhere in the tuple
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*
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* check to see if desired att is null
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* check to see if any preceding bits are null...
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*/
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int byte = attnum >> 3;
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int finalbit = attnum & 0x07;
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#ifdef IN_MACRO
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/* This is handled in the macro */
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if (att_isnull(attnum, bp))
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/* check for nulls "before" final bit of last byte */
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if ((~bp[byte]) & ((1 << finalbit) - 1))
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slow = true;
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else
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{
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if (isnull)
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*isnull = true;
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return (Datum) NULL;
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}
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#endif
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/* check for nulls in any "earlier" bytes */
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int i;
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/*
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* Now check to see if any preceding bits are null...
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*/
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{
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int byte = attnum >> 3;
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int finalbit = attnum & 0x07;
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/* check for nulls "before" final bit of last byte */
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if ((~bp[byte]) & ((1 << finalbit) - 1))
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slow = true;
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else
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for (i = 0; i < byte; i++)
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{
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/* check for nulls in any "earlier" bytes */
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int i;
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for (i = 0; i < byte; i++)
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if (bp[i] != 0xFF)
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{
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if (bp[i] != 0xFF)
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{
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slow = true;
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break;
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}
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slow = true;
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break;
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}
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}
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}
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@ -567,8 +528,7 @@ heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
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Assert(tup);
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/* Currently, no sys attribute ever reads as NULL. */
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if (isnull)
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*isnull = false;
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*isnull = false;
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switch (attnum)
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{
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/common/indextuple.c,v 1.90 2010/01/02 16:57:33 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/access/common/indextuple.c,v 1.91 2010/01/10 04:26:36 rhaas Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -200,8 +200,7 @@ index_form_tuple(TupleDesc tupleDescriptor,
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Datum
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nocache_index_getattr(IndexTuple tup,
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int attnum,
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TupleDesc tupleDesc,
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bool *isnull)
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TupleDesc tupleDesc)
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{
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Form_pg_attribute *att = tupleDesc->attrs;
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char *tp; /* ptr to data part of tuple */
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@ -210,8 +209,6 @@ nocache_index_getattr(IndexTuple tup,
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int data_off; /* tuple data offset */
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int off; /* current offset within data */
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(void) isnull; /* not used */
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/* ----------------
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* Three cases:
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*
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@ -221,31 +218,11 @@ nocache_index_getattr(IndexTuple tup,
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* ----------------
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*/
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#ifdef IN_MACRO
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/* This is handled in the macro */
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Assert(PointerIsValid(isnull));
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Assert(attnum > 0);
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*isnull = false;
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#endif
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data_off = IndexInfoFindDataOffset(tup->t_info);
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attnum--;
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if (!IndexTupleHasNulls(tup))
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{
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#ifdef IN_MACRO
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/* This is handled in the macro */
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if (att[attnum]->attcacheoff >= 0)
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{
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return fetchatt(att[attnum],
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(char *) tup + data_off +
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att[attnum]->attcacheoff);
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}
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#endif
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}
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else
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if (IndexTupleHasNulls(tup))
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{
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/*
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* there's a null somewhere in the tuple
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@ -256,16 +233,6 @@ nocache_index_getattr(IndexTuple tup,
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/* XXX "knows" t_bits are just after fixed tuple header! */
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bp = (bits8 *) ((char *) tup + sizeof(IndexTupleData));
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#ifdef IN_MACRO
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/* This is handled in the macro */
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if (att_isnull(attnum, bp))
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{
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*isnull = true;
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return (Datum) NULL;
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}
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#endif
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/*
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* Now check to see if any preceding bits are null...
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*/
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.280 2010/01/02 16:57:34 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.281 2010/01/10 04:26:36 rhaas Exp $
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*
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*
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* INTERFACE ROUTINES
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@ -834,7 +834,7 @@ fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
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return (
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(attnum) > 0 ?
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(
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((isnull) ? (*(isnull) = false) : (dummyret) NULL),
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(*(isnull) = false),
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HeapTupleNoNulls(tup) ?
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(
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(tupleDesc)->attrs[(attnum) - 1]->attcacheoff >= 0 ?
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@ -844,18 +844,18 @@ fastgetattr(HeapTuple tup, int attnum, TupleDesc tupleDesc,
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(tupleDesc)->attrs[(attnum) - 1]->attcacheoff)
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)
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:
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nocachegetattr((tup), (attnum), (tupleDesc), (isnull))
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nocachegetattr((tup), (attnum), (tupleDesc))
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)
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:
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(
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att_isnull((attnum) - 1, (tup)->t_data->t_bits) ?
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(
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((isnull) ? (*(isnull) = true) : (dummyret) NULL),
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(*(isnull) = true),
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(Datum) NULL
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)
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:
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(
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nocachegetattr((tup), (attnum), (tupleDesc), (isnull))
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nocachegetattr((tup), (attnum), (tupleDesc))
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)
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)
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)
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