/ Check-in [9bbca48b]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Fix a problem in calculating the costs of "OR" scans.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:9bbca48b42e4fe16f2188e18dc736da30a96435c
User & Date: dan 2014-04-30 18:11:55
Context
2014-05-01
10:19
Update a test case in wal2.test that explicitly corrupts a checksum in the wal file to account for the fact that the first byte of said checksum may initially be 0xFF. check-in: 2b935bde user: dan tags: trunk
2014-04-30
20:32
Merge in all recent changes and enhancements from trunk. check-in: 84243f84 user: drh tags: win32-none
18:11
Fix a problem in calculating the costs of "OR" scans. check-in: 9bbca48b user: dan tags: trunk
15:22
Modify the way the costs of various query plans are estimated. If the user supplies a likelihood() value (or equivalent) on an indexed WHERE constraint, use it to estimate the number of index rows visited. check-in: 90e36676 user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/where.c.

4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
....
4790
4791
4792
4793
4794
4795
4796

4797
4798
4799
4800
4801
4802
4803
....
4808
4809
4810
4811
4812
4813
4814












4815
4816
4817
4818
4819
4820
4821
4822
  WhereClause *pWC;
  WhereLoop *pNew;
  WhereTerm *pTerm, *pWCEnd;
  int rc = SQLITE_OK;
  int iCur;
  WhereClause tempWC;
  WhereLoopBuilder sSubBuild;
  WhereOrSet sSum, sCur, sPrev;
  struct SrcList_item *pItem;
  
  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));
................................................................................
        if( sCur.n==0 ){
          sSum.n = 0;
          break;
        }else if( once ){
          whereOrMove(&sSum, &sCur);
          once = 0;
        }else{

          whereOrMove(&sPrev, &sSum);
          sSum.n = 0;
          for(i=0; i<sPrev.n; i++){
            for(j=0; j<sCur.n; j++){
              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
                            sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
                            sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
................................................................................
      pNew->nLTerm = 1;
      pNew->aLTerm[0] = pTerm;
      pNew->wsFlags = WHERE_MULTI_OR;
      pNew->rSetup = 0;
      pNew->iSortIdx = 0;
      memset(&pNew->u, 0, sizeof(pNew->u));
      for(i=0; rc==SQLITE_OK && i<sSum.n; i++){












        pNew->rRun = sSum.a[i].rRun;
        pNew->nOut = sSum.a[i].nOut;
        pNew->prereq = sSum.a[i].prereq;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
  return rc;







|







 







>







 







>
>
>
>
>
>
>
>
>
>
>
>
|







4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
....
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
....
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
  WhereClause *pWC;
  WhereLoop *pNew;
  WhereTerm *pTerm, *pWCEnd;
  int rc = SQLITE_OK;
  int iCur;
  WhereClause tempWC;
  WhereLoopBuilder sSubBuild;
  WhereOrSet sSum, sCur;
  struct SrcList_item *pItem;
  
  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));
................................................................................
        if( sCur.n==0 ){
          sSum.n = 0;
          break;
        }else if( once ){
          whereOrMove(&sSum, &sCur);
          once = 0;
        }else{
          WhereOrSet sPrev;
          whereOrMove(&sPrev, &sSum);
          sSum.n = 0;
          for(i=0; i<sPrev.n; i++){
            for(j=0; j<sCur.n; j++){
              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
                            sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
                            sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
................................................................................
      pNew->nLTerm = 1;
      pNew->aLTerm[0] = pTerm;
      pNew->wsFlags = WHERE_MULTI_OR;
      pNew->rSetup = 0;
      pNew->iSortIdx = 0;
      memset(&pNew->u, 0, sizeof(pNew->u));
      for(i=0; rc==SQLITE_OK && i<sSum.n; i++){
        /* TUNING: Currently sSum.a[i].rRun is set to the sum of the costs
        ** of all sub-scans required by the OR-scan. However, due to rounding
        ** errors, it may be that the cost of the OR-scan is equal to its
        ** most expensive sub-scan. Add the smallest possible penalty 
        ** (equivalent to multiplying the cost by 1.07) to ensure that 
        ** this does not happen. Otherwise, for WHERE clauses such as the
        ** following where there is an index on "y":
        **
        **     WHERE likelihood(x=?, 0.99) OR y=?
        **
        ** the planner may elect to "OR" together a full-table scan and an
        ** index lookup. And other similarly odd results.  */
        pNew->rRun = sSum.a[i].rRun + 1;
        pNew->nOut = sSum.a[i].nOut;
        pNew->prereq = sSum.a[i].prereq;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
  return rc;

Changes to test/cost.test.

146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161






162
163
164
165
166
167
168
  ORDER BY a
} {
  0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b>? AND b<?)} 
  0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

#set sqlite_where_trace 0xfff
do_eqp_test 7.3 {
  SELECT rowid FROM t1
  WHERE (+b IS NULL AND c NOT NULL AND d NOT NULL)
        OR (b NOT NULL AND c IS NULL AND d NOT NULL)
        OR (b NOT NULL AND c NOT NULL AND d IS NULL)
} {
  0 0 0 {SCAN TABLE t1}
}







#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 8.1 {
  CREATE TABLE composer(
    cid INTEGER PRIMARY KEY,







<








>
>
>
>
>
>







146
147
148
149
150
151
152

153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
  ORDER BY a
} {
  0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b>? AND b<?)} 
  0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}


do_eqp_test 7.3 {
  SELECT rowid FROM t1
  WHERE (+b IS NULL AND c NOT NULL AND d NOT NULL)
        OR (b NOT NULL AND c IS NULL AND d NOT NULL)
        OR (b NOT NULL AND c NOT NULL AND d IS NULL)
} {
  0 0 0 {SCAN TABLE t1}
}

do_eqp_test 7.4 {
  SELECT rowid FROM t1 WHERE (+b IS NULL AND c NOT NULL) OR c IS NULL
} {
  0 0 0 {SCAN TABLE t1}
}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 8.1 {
  CREATE TABLE composer(
    cid INTEGER PRIMARY KEY,