1 /*-------------------------------------------------------------------------
4 * POSTGRES internal relation scan descriptor definitions.
7 * Copyright (c) 1994, Regents of the University of California
9 * $Id: relscan.h,v 1.10 1997/11/24 05:09:39 momjian Exp $
11 *-------------------------------------------------------------------------
16 #include <storage/buf.h>
17 #include <utils/rel.h>
18 #include <access/htup.h>
20 typedef ItemPointerData MarkData;
22 typedef struct HeapScanDescData
24 Relation rs_rd; /* pointer to relation descriptor */
25 HeapTuple rs_ptup; /* previous tuple in scan */
26 HeapTuple rs_ctup; /* current tuple in scan */
27 HeapTuple rs_ntup; /* next tuple in scan */
28 Buffer rs_pbuf; /* previous buffer in scan */
29 Buffer rs_cbuf; /* current buffer in scan */
30 Buffer rs_nbuf; /* next buffer in scan */
31 ItemPointerData rs_mptid; /* marked previous tid */
32 ItemPointerData rs_mctid; /* marked current tid */
33 ItemPointerData rs_mntid; /* marked next tid */
34 ItemPointerData rs_mcd; /* marked current delta XXX ??? */
35 bool rs_atend; /* restart scan at end? */
36 bool rs_seeself; /* see self or not */
37 uint16 rs_cdelta; /* current delta in chain */
38 uint16 rs_nkeys; /* number of attributes in keys */
39 ScanKey rs_key; /* key descriptors */
42 typedef HeapScanDescData *HeapScanDesc;
44 typedef struct IndexScanDescData
46 Relation relation; /* relation descriptor */
47 void *opaque; /* am-specific slot */
48 ItemPointerData previousItemData; /* previous index pointer */
49 ItemPointerData currentItemData; /* current index pointer */
50 ItemPointerData nextItemData; /* next index pointer */
51 MarkData previousMarkData; /* marked previous pointer */
52 MarkData currentMarkData;/* marked current pointer */
53 MarkData nextMarkData; /* marked next pointer */
54 uint8 flags; /* scan position flags */
55 bool scanFromEnd; /* restart scan at end? */
56 uint16 numberOfKeys; /* number of key attributes */
57 ScanKey keyData; /* key descriptor */
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 */