Method TestBlock

storage/connect/tabdos.cpp:1625–1663

/ Block optimization: evaluate the block index filter against */ the min and max values of this block and return: */ RC_OK: if some records in the block can meet filter criteria. */ RC_NF: if no record in the block can meet filter criteria. */ RC_EF: if no record in the remaining file can meet filter criteria.*/ In addition, temporarily suppress filtering if a

/*  the block meet filter criteria.                                    */
/***********************************************************************/
int TDBDOS::TestBlock(PGLOBAL g)
  {
  int rc = RC_OK;

  if (To_BlkFil && Beval != 2) {
    // Check for block filtering evaluation
    if (Beval == 1) {
      // Filter was removed for last block, restore it
      To_Filter = SavFil;
      SavFil = NULL;
      } // endif Beval

    // Check for valid records in new block
    switch (Beval = To_BlkFil->BlockEval(g)) {
      case -2:            // No more valid values in file
        rc = RC_EF;
        break;
      case -1:            // No valid values in block
        rc = RC_NF;
        break;
      case 1:             // All block values are valid
      case 2:             // All subsequent file values are Ok
        // Before suppressing the filter for the block(s) it is
        // necessary to reset the filtered columns to NOT_READ
        // so their new values are retrieved by the SELECT list.
        if (To_Filter) // Can be NULL when externally called (XDB)
          To_Filter->Reset();

        SavFil = To_Filter;
        To_Filter = NULL; // So remove filter
      } // endswitch Beval

    if (trace(1))
      htrc("BF Eval Beval=%d\n", Beval);

    } // endif To_BlkFil

  return rc;
  } // end of TestBlock

/***********************************************************************/
/*  Check whether we have to create/update permanent indexes.          */