src/include/utils/tqual.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * tqual.h--
   4  *        POSTGRES "time" qualification definitions.
   5  *
   6  *
   7  * Copyright (c) 1994, Regents of the University of California
   8  *
   9  * $Id: tqual.h,v 1.12 1998/04/24 14:43:33 momjian Exp $
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13 #ifndef TQUAL_H
  14 #define TQUAL_H
  15
  16 #include <access/htup.h>
  17
  18 extern TransactionId HeapSpecialTransactionId;
  19 extern CommandId HeapSpecialCommandId;
  20
  21 /*
  22  * HeapTupleSatisfiesVisibility --
  23  *              True iff heap tuple satsifies a time qual.
  24  *
  25  * Note:
  26  *              Assumes heap tuple is valid.
  27  */
  28 #define HeapTupleSatisfiesVisibility(tuple, seeself) \
  29 ( \
  30         TransactionIdEquals((tuple)->t_xmax, AmiTransactionId) ? \
  31                 false \
  32         : \
  33         ( \
  34                 ((seeself) == true || heapisoverride()) ? \
  35                         HeapTupleSatisfiesItself(tuple) \
  36                 : \
  37                         HeapTupleSatisfiesNow(tuple) \
  38         ) \
  39 )
  40
  41 #define heapisoverride() \
  42 ( \
  43         (!TransactionIdIsValid(HeapSpecialTransactionId)) ? \
  44                 false \
  45         : \
  46         ( \
  47                 (!TransactionIdEquals(GetCurrentTransactionId(), \
  48                                                          HeapSpecialTransactionId) || \
  49                  GetCurrentCommandId() != HeapSpecialCommandId) ? \
  50                 ( \
  51                         HeapSpecialTransactionId = InvalidTransactionId, \
  52                         false \
  53                 ) \
  54                 : \
  55                         true \
  56         ) \
  57 )
  58
  59 extern bool HeapTupleSatisfiesItself(HeapTuple tuple);
  60 extern bool HeapTupleSatisfiesNow(HeapTuple tuple);
  61
  62 extern void setheapoverride(bool on);
  63
  64
  65 #endif                                                  /* TQUAL_H */