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Overview
Comment:Disable the flattening optimization if the sub-query is a recursive CTE.
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Timelines: family | ancestors | descendants | both | common-table-expr
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SHA1: 9472f6d820a7fb233936d9b8f7a39c9d4c4d6d73
User & Date: dan 2014-01-15 14:17:31
Context
2014-01-15
14:40
Don't try to verify the schema of transient table (such as generated inside a WITH clause) when generating code for "IN table" operators. check-in: 860aa936 user: drh tags: common-table-expr
14:17
Disable the flattening optimization if the sub-query is a recursive CTE. check-in: 9472f6d8 user: dan tags: common-table-expr
02:40
Use the user-supplied table name in WITH RECURSIVE tables as the internal name of the table and the name of the table in VDBE comments. check-in: a2933023 user: drh tags: common-table-expr
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/expr.c.

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      }

    }
  }
  return pNew;
}






With *withDup(sqlite3 *db, With *p){
  With *pRet = 0;
  if( p ){
    int nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
    pRet = sqlite3DbMallocZero(db, nByte);
    if( pRet ){
      int i;
      pRet->nCte = p->nCte;
................................................................................
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->pRightmost = 0;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->pWith = withDup(db, p->pWith);

  pNew->pRecurse = p->pRecurse;
  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
  return 0;
}







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      }

    }
  }
  return pNew;
}

/*
** Create and return a deep copy of the object passed as the second 
** argument. If an OOM condition is encountered, NULL is returned
** and the db->mallocFailed flag set.
*/
static With *withDup(sqlite3 *db, With *p){
  With *pRet = 0;
  if( p ){
    int nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
    pRet = sqlite3DbMallocZero(db, nByte);
    if( pRet ){
      int i;
      pRet->nCte = p->nCte;
................................................................................
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->pRightmost = 0;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->pWith = withDup(db, p->pWith);
  assert( p->pRecurse==0 );
  pNew->pRecurse = 0;
  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
  return 0;
}

Changes to src/parse.y.

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where_opt(A) ::= .                    {A = 0;}
where_opt(A) ::= WHERE expr(X).       {A = X.pExpr;}

////////////////////////// The UPDATE command ////////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
        where_opt(W) orderby_opt(O) limit_opt(L).  {

  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3ExprListCheckLength(pParse,Y,"set list"); 
  W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "UPDATE");
  sqlite3Update(pParse,X,Y,W,R);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT







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where_opt(A) ::= .                    {A = 0;}
where_opt(A) ::= WHERE expr(X).       {A = X.pExpr;}

////////////////////////// The UPDATE command ////////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= with(C) UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y)
        where_opt(W) orderby_opt(O) limit_opt(L).  {
  sqlite3WithPush(pParse, C);
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3ExprListCheckLength(pParse,Y,"set list"); 
  W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "UPDATE");
  sqlite3Update(pParse,X,Y,W,R);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT

Changes to src/select.c.

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**
** The code generated for this simpification gives the same result
** but only has to scan the data once.  And because indices might 
** exist on the table t1, a complete scan of the data might be
** avoided.
**
** Flattening is only attempted if all of the following are true:


**
**   (1)  The subquery and the outer query do not both use aggregates.
**
**   (2)  The subquery is not an aggregate or the outer query is not a join.
**
**   (3)  The subquery is not the right operand of a left outer join
**        (Originally ticket #306.  Strengthened by ticket #3300)
................................................................................
  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
  pSubitem = &pSrc->a[iFrom];
  iParent = pSubitem->iCursor;
  pSub = pSubitem->pSelect;
  assert( pSub!=0 );

  if( isAgg && subqueryIsAgg ) return 0;                 /* Restriction (1)  */
  if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;          /* Restriction (2)  */
  pSubSrc = pSub->pSrc;
  assert( pSubSrc );
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET







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**
** The code generated for this simpification gives the same result
** but only has to scan the data once.  And because indices might 
** exist on the table t1, a complete scan of the data might be
** avoided.
**
** Flattening is only attempted if all of the following are true:
**
**   (0)  The subquery is not a recursive CTE.
**
**   (1)  The subquery and the outer query do not both use aggregates.
**
**   (2)  The subquery is not an aggregate or the outer query is not a join.
**
**   (3)  The subquery is not the right operand of a left outer join
**        (Originally ticket #306.  Strengthened by ticket #3300)
................................................................................
  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
  pSubitem = &pSrc->a[iFrom];
  iParent = pSubitem->iCursor;
  pSub = pSubitem->pSelect;
  assert( pSub!=0 );
  if( pSub->pRecurse ) return 0;                         /* Restriction (0)  */
  if( isAgg && subqueryIsAgg ) return 0;                 /* Restriction (1)  */
  if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;          /* Restriction (2)  */
  pSubSrc = pSub->pSrc;
  assert( pSubSrc );
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET

Changes to test/with1.test.

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  SELECT x FROM i LIMIT 20;
} {1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0}

do_execsql_test 5.5 {
  WITH i(x) AS ( VALUES(1) UNION SELECT (x+1)%10 FROM i)
  SELECT x FROM i LIMIT 20;
} {1 2 3 4 5 6 7 8 9 0}













































finish_test











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  SELECT x FROM i LIMIT 20;
} {1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0}

do_execsql_test 5.5 {
  WITH i(x) AS ( VALUES(1) UNION SELECT (x+1)%10 FROM i)
  SELECT x FROM i LIMIT 20;
} {1 2 3 4 5 6 7 8 9 0}

#-------------------------------------------------------------------------
#
do_execsql_test 6.1 {
  CREATE TABLE f(
      id INTEGER PRIMARY KEY, parentid REFERENCES f, name TEXT
  );

  INSERT INTO f VALUES(0, NULL, '');
  INSERT INTO f VALUES(1, 0, 'bin');
    INSERT INTO f VALUES(2, 1, 'true');
    INSERT INTO f VALUES(3, 1, 'false');
    INSERT INTO f VALUES(4, 1, 'ls');
    INSERT INTO f VALUES(5, 1, 'grep');
  INSERT INTO f VALUES(6, 0, 'etc');
    INSERT INTO f VALUES(7, 6, 'rc.d');
      INSERT INTO f VALUES(8, 7, 'rc.apache');
      INSERT INTO f VALUES(9, 7, 'rc.samba');
  INSERT INTO f VALUES(10, 0, 'home');
    INSERT INTO f VALUES(11, 10, 'dan');
      INSERT INTO f VALUES(12, 11, 'public_html');
        INSERT INTO f VALUES(13, 12, 'index.html');
          INSERT INTO f VALUES(14, 13, 'logo.gif');
}

do_execsql_test 6.2 {
  WITH flat(fid, fpath) AS (
    SELECT id, '' FROM f WHERE parentid IS NULL
    UNION ALL
    SELECT id, fpath || '/' || name FROM f, flat WHERE +parentid=+fid
  )
  SELECT fpath FROM flat WHERE fpath!='' ORDER BY 1;
} {
  /bin 
  /bin/false /bin/grep /bin/ls /bin/true 
  /etc 
  /etc/rc.d 
  /etc/rc.d/rc.apache /etc/rc.d/rc.samba 
  /home 
  /home/dan 
  /home/dan/public_html 
  /home/dan/public_html/index.html 
  /home/dan/public_html/index.html/logo.gif
}

finish_test