granicus.if.org Git - postgresql/blob - src/include/access/relscan.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * relscan.h--
   4  *    POSTGRES internal relation scan descriptor definitions.
   5  *
   6  *
   7  * Copyright (c) 1994, Regents of the University of California
   8  *
   9  * $Id: relscan.h,v 1.4 1996/11/03 08:17:22 scrappy Exp $
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13 #ifndef RELSCAN_H
  14 #define RELSCAN_H
  15
  16 #include "utils/rel.h"
  17 #include "utils/tqual.h"
  18 #include "storage/buf.h"
  19
  20 typedef ItemPointerData MarkData;
  21
  22 typedef struct HeapScanDescData {
  23         Relation        rs_rd;          /* pointer to relation descriptor */
  24         HeapTuple       rs_ptup;        /* previous tuple in scan */
  25         HeapTuple       rs_ctup;        /* current tuple in scan */
  26         HeapTuple       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         bool            rs_atend;       /* restart scan at end? */
  35         TimeQual        rs_tr;          /* time qualification */
  36         uint16          rs_cdelta;      /* current delta in chain */
  37         uint16          rs_nkeys;       /* number of attributes in keys */
  38         ScanKey         rs_key;         /* key descriptors */
  39 } HeapScanDescData;
  40
  41 typedef HeapScanDescData *HeapScanDesc;
  42
  43 typedef struct IndexScanDescData {
  44         Relation        relation;               /* relation descriptor */
  45         void            *opaque;                /* am-specific slot */
  46         ItemPointerData previousItemData;       /* previous index pointer */
  47         ItemPointerData currentItemData;        /* current index pointer */
  48         ItemPointerData nextItemData;           /* next index pointer */
  49         MarkData        previousMarkData;       /* marked previous pointer */
  50         MarkData        currentMarkData;        /* marked current  pointer */
  51         MarkData        nextMarkData;           /* marked next pointer */
  52         uint8           flags;                  /* scan position flags */
  53         bool            scanFromEnd;            /* restart scan at end? */
  54         uint16          numberOfKeys;           /* number of key attributes */
  55         ScanKey         keyData;                /* key descriptor */
  56 } IndexScanDescData;
  57
  58 typedef IndexScanDescData       *IndexScanDesc;
  59
  60 /* ----------------
  61  *      IndexScanDescPtr is used in the executor where we have to
  62  *      keep track of several index scans when using several indices
  63  *      - cim 9/10/89
  64  * ----------------
  65  */
  66 typedef IndexScanDesc           *IndexScanDescPtr;
  67
  68 /*
  69  * HeapScanIsValid --
  70  *      True iff the heap scan is valid.
  71  */
  72 #define HeapScanIsValid(scan) PointerIsValid(scan)
  73
  74 /*
  75  * IndexScanIsValid --
  76  *      True iff the index scan is valid.
  77  */
  78 #define IndexScanIsValid(scan) PointerIsValid(scan)
  79
  80 #endif  /* RELSCAN_H */