1 /*-------------------------------------------------------------------------
4 * POSTGRES internal relation scan descriptor definitions.
7 * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
8 * Portions Copyright (c) 1994, Regents of the University of California
10 * $Id: relscan.h,v 1.19 2000/03/14 23:52:00 tgl Exp $
12 *-------------------------------------------------------------------------
17 #include "utils/tqual.h"
19 typedef ItemPointerData MarkData;
21 typedef struct HeapScanDescData
23 Relation rs_rd; /* pointer to relation descriptor */
24 HeapTupleData rs_ptup; /* previous tuple in scan */
25 HeapTupleData rs_ctup; /* current tuple in scan */
26 HeapTupleData rs_ntup; /* next tuple in scan */
27 Buffer rs_pbuf; /* previous buffer in scan */
28 Buffer rs_cbuf; /* current buffer in scan */
29 Buffer rs_nbuf; /* next buffer in scan */
30 ItemPointerData rs_mptid; /* marked previous tid */
31 ItemPointerData rs_mctid; /* marked current tid */
32 ItemPointerData rs_mntid; /* marked next tid */
33 ItemPointerData rs_mcd; /* marked current delta XXX ??? */
34 Snapshot rs_snapshot; /* snapshot to see */
35 bool rs_atend; /* restart scan at end? */
36 uint16 rs_cdelta; /* current delta in chain */
37 uint16 rs_nkeys; /* number of attributes in keys */
38 ScanKey rs_key; /* key descriptors */
41 typedef HeapScanDescData *HeapScanDesc;
43 typedef struct IndexScanDescData
45 Relation relation; /* relation descriptor */
46 void *opaque; /* am-specific slot */
47 ItemPointerData previousItemData; /* previous index pointer */
48 ItemPointerData currentItemData; /* current index pointer */
49 ItemPointerData nextItemData; /* next index pointer */
50 MarkData previousMarkData; /* marked previous pointer */
51 MarkData currentMarkData;/* marked current pointer */
52 MarkData nextMarkData; /* marked next pointer */
53 uint8 flags; /* scan position flags */
54 bool scanFromEnd; /* restart scan at end? */
55 uint16 numberOfKeys; /* number of key attributes */
56 ScanKey keyData; /* key descriptor */
57 FmgrInfo fn_getnext; /* cached lookup info for am's getnext fn */
60 typedef IndexScanDescData *IndexScanDesc;
63 * IndexScanDescPtr is used in the executor where we have to
64 * keep track of several index scans when using several indices
68 typedef IndexScanDesc *IndexScanDescPtr;
72 * True iff the heap scan is valid.
74 #define HeapScanIsValid(scan) PointerIsValid(scan)
78 * True iff the index scan is valid.
80 #define IndexScanIsValid(scan) PointerIsValid(scan)
82 #endif /* RELSCAN_H */