diff options
Diffstat (limited to 'src/include/executor/tuptable.h')
| -rw-r--r-- | src/include/executor/tuptable.h | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h index b506651fbb..8531835134 100644 --- a/src/include/executor/tuptable.h +++ b/src/include/executor/tuptable.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/executor/tuptable.h,v 1.31 2006/06/16 18:42:23 tgl Exp $ + * $PostgreSQL: pgsql/src/include/executor/tuptable.h,v 1.32 2006/06/27 02:51:40 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -23,7 +23,8 @@ * independent TupleTableSlots. There are several cases we need to handle: * 1. physical tuple in a disk buffer page * 2. physical tuple constructed in palloc'ed memory - * 3. "virtual" tuple consisting of Datum/isnull arrays + * 3. "minimal" physical tuple constructed in palloc'ed memory + * 4. "virtual" tuple consisting of Datum/isnull arrays * * The first two cases are similar in that they both deal with "materialized" * tuples, but resource management is different. For a tuple in a disk page @@ -31,6 +32,11 @@ * to the tuple is dropped; while for a palloc'd tuple we usually want the * tuple pfree'd when the TupleTableSlot's reference is dropped. * + * A "minimal" tuple is handled similarly to a palloc'd regular tuple. + * At present, minimal tuples never are stored in buffers, so there is no + * parallel to case 1. Note that a minimal tuple has no "system columns". + * (Actually, it could have an OID, but we have no need to access the OID.) + * * A "virtual" tuple is an optimization used to minimize physical data * copying in a nest of plan nodes. Any pass-by-reference Datums in the * tuple point to storage that is not directly associated with the @@ -83,6 +89,15 @@ * tts_values/tts_isnull are allocated when a descriptor is assigned to the * slot; they are of length equal to the descriptor's natts. * + * tts_mintuple must always be NULL if the slot does not hold a "minimal" + * tuple. When it does, tts_mintuple points to the actual MinimalTupleData + * object (the thing to be pfree'd if tts_shouldFree is true). In this case + * tts_tuple points at tts_minhdr and the fields of that are set correctly + * for access to the minimal tuple; in particular, tts_minhdr.t_data points + * MINIMAL_TUPLE_OFFSET bytes before tts_mintuple. (tts_mintuple is therefore + * redundant, but for code simplicity we store it explicitly anyway.) This + * case otherwise behaves identically to the regular-physical-tuple case. + * * tts_slow/tts_off are saved state for slot_deform_tuple, and should not * be touched by any other code. *---------- @@ -100,6 +115,8 @@ typedef struct TupleTableSlot int tts_nvalid; /* # of valid values in tts_values */ Datum *tts_values; /* current per-attribute values */ bool *tts_isnull; /* current per-attribute isnull flags */ + MinimalTuple tts_mintuple; /* set if it's a minimal tuple, else NULL */ + HeapTupleData tts_minhdr; /* workspace if it's a minimal tuple */ long tts_off; /* saved state for slot_deform_tuple */ } TupleTableSlot; @@ -133,10 +150,14 @@ extern TupleTableSlot *ExecStoreTuple(HeapTuple tuple, TupleTableSlot *slot, Buffer buffer, bool shouldFree); +extern TupleTableSlot *ExecStoreMinimalTuple(MinimalTuple mtup, + TupleTableSlot *slot, + bool shouldFree); extern TupleTableSlot *ExecClearTuple(TupleTableSlot *slot); extern TupleTableSlot *ExecStoreVirtualTuple(TupleTableSlot *slot); extern TupleTableSlot *ExecStoreAllNullTuple(TupleTableSlot *slot); extern HeapTuple ExecCopySlotTuple(TupleTableSlot *slot); +extern MinimalTuple ExecCopySlotMinimalTuple(TupleTableSlot *slot); extern HeapTuple ExecFetchSlotTuple(TupleTableSlot *slot); extern HeapTuple ExecMaterializeSlot(TupleTableSlot *slot); extern TupleTableSlot *ExecCopySlot(TupleTableSlot *dstslot, |