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  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  * $Id: relscan.h,v 1.20 2001/01/24 19:43:19 momjian Exp $
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #ifndef RELSCAN_H
  15 #define RELSCAN_H
  16
  17 #include "utils/tqual.h"
  18
  19 typedef ItemPointerData MarkData;
  20
  21 typedef struct HeapScanDescData
  22 {
  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 */
  39 } HeapScanDescData;
  40
  41 typedef HeapScanDescData *HeapScanDesc;
  42
  43 typedef struct IndexScanDescData
  44 {
  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 */
  58 } IndexScanDescData;
  59
  60 typedef IndexScanDescData *IndexScanDesc;
  61
  62 /* ----------------
  63  *              IndexScanDescPtr is used in the executor where we have to
  64  *              keep track of several index scans when using several indices
  65  *              - cim 9/10/89
  66  * ----------------
  67  */
  68 typedef IndexScanDesc *IndexScanDescPtr;
  69
  70 /*
  71  * HeapScanIsValid
  72  *              True iff the heap scan is valid.
  73  */
  74 #define HeapScanIsValid(scan) PointerIsValid(scan)
  75
  76 /*
  77  * IndexScanIsValid
  78  *              True iff the index scan is valid.
  79  */
  80 #define IndexScanIsValid(scan) PointerIsValid(scan)
  81
  82 #endif   /* RELSCAN_H */