SQLite

    int regRowset = 0;                        /* Register for RowSet object */
    int regRowid = 0;                         /* Register holding rowid */
    int iLoopBody = sqlite3VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
    Table *pTab = pTabItem->pTab;
   
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->eOperator & WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;

    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the 
    ** correct response for the end-of-loop code (the OP_Return) is to 
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      if( HasRowid(pTab) ){
        regRowset = ++pParse->nMem;

        sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
      }else{
        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
        regRowset = pParse->nTab++;
        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol);
        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
      }
      regRowid = ++pParse->nMem;
    }
    iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND z
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite3WhereBegin() below.

        assert( pSubWInfo || pParse->nErr || db->mallocFailed );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){

            int r;
            int addr;             /* Address just past Gosub coded below */
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            if( HasRowid(pTab) ){
              r = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, regRowid, 0);

              addr = sqlite3VdbeCurrentAddr(v)+2;
              sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, addr, r, iSet);

              VdbeCoverage(v);
            }else{
              Index *pPk = sqlite3PrimaryKeyIndex(pTab);
              int nPk = pPk->nKeyCol;
              int iPk;

              /* Read the PK into an array of temp registers. */
              r = sqlite3GetTempRange(pParse, nPk);
              for(iPk=0; iPk<nPk; iPk++){
                int iCol = pPk->aiColumn[iPk];
                sqlite3ExprCodeGetColumn(pParse, pTab, iCol, iCur, r+iPk, 0);
              }

              /* Check if the temp table already contains this key. If so,
              ** the row has already been included in the result set and
              ** can be ignored (by jumping past the Gosub below). Otherwise,
              ** insert the key into the temp table and proceed with processing
              ** the row.
              **
              ** Use some of the same optimizations as OP_RowSetTest: If iSet
              ** is zero, assume that the key cannot already be present in
              ** the temp table. And if iSet is -1, assume that there is no 
              ** need to insert the key into the temp table, as it will never 
              ** be tested for.  */ 
              if( iSet ){
                addr = sqlite3VdbeCurrentAddr(v) + 2 + ((iSet>0) ? 2 : 0);
                sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, addr, r, nPk);
              }
              if( iSet>=0 ){
                sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid);
                sqlite3VdbeAddOp3(v, OP_IdxInsert, regRowset, regRowid, 0);
                if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
              }

              /* Release the array of temp registers */
              sqlite3ReleaseTempRange(pParse, r, nPk);
            }
            assert( db->mallocFailed 
                 || iSet==0 || addr==(sqlite3VdbeCurrentAddr(v)+1) );
          }
          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.

  
  pWC = pBuilder->pWC;
  if( pWInfo->wctrlFlags & WHERE_AND_ONLY ) return SQLITE_OK;
  pWCEnd = pWC->a + pWC->nTerm;
  pNew = pBuilder->pNew;
  memset(&sSum, 0, sizeof(sSum));
  pItem = pWInfo->pTabList->a + pNew->iTab;

  iCur = pItem->iCursor;

  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
    if( (pTerm->eOperator & WO_OR)!=0
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;

# 2014-03-31
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# The focus of this file is testing the OR optimization on WITHOUT ROWID 
# tables.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix whereI

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c, PRIMARY KEY(a)) WITHOUT ROWID;
  INSERT INTO t1 VALUES(1, 'a', 'z');
  INSERT INTO t1 VALUES(2, 'b', 'y');
  INSERT INTO t1 VALUES(3, 'c', 'x');
  INSERT INTO t1 VALUES(4, 'd', 'w');
  CREATE INDEX i1 ON t1(b);
  CREATE INDEX i2 ON t1(c);
}

do_eqp_test 1.1 {
  SELECT a FROM t1 WHERE b='b' OR c='x'
} {
  0 0 0 {SEARCH TABLE t1 USING INDEX i1 (b=?)} 
  0 0 0 {SEARCH TABLE t1 USING INDEX i2 (c=?)}
}

do_execsql_test 1.2 {
  SELECT a FROM t1 WHERE b='b' OR c='x'
} {2 3}

do_execsql_test 1.3 {
  SELECT a FROM t1 WHERE b='a' OR c='z'
} {1}

#----------------------------------------------------------------------
# Try that again, this time with non integer PRIMARY KEY values.
#
do_execsql_test 2.0 {
  CREATE TABLE t2(a, b, c, PRIMARY KEY(a)) WITHOUT ROWID;
  INSERT INTO t2 VALUES('i', 'a', 'z');
  INSERT INTO t2 VALUES('ii', 'b', 'y');
  INSERT INTO t2 VALUES('iii', 'c', 'x');
  INSERT INTO t2 VALUES('iv', 'd', 'w');
  CREATE INDEX i3 ON t2(b);
  CREATE INDEX i4 ON t2(c);
}

do_eqp_test 2.1 {
  SELECT a FROM t2 WHERE b='b' OR c='x'
} {
  0 0 0 {SEARCH TABLE t2 USING INDEX i3 (b=?)} 
  0 0 0 {SEARCH TABLE t2 USING INDEX i4 (c=?)}
}

do_execsql_test 2.2 {
  SELECT a FROM t2 WHERE b='b' OR c='x'
} {ii iii}

do_execsql_test 2.3 {
  SELECT a FROM t2 WHERE b='a' OR c='z'
} {i}

finish_test