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Overview
Comment:Code simplification in sqlite3ColumnsFromExprList(). Update the %z format code so that it works with buffers obtained from sqlite3DbMalloc(). Add a testcase for the slow column name uniquifier.
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SHA1: 9272426057b6cb2d913519ff4c97aa6e211f7d51
User & Date: drh 2015-11-14 22:04:22.826
Context
2015-11-15
11:13
Fix the column name uniquifier so that it works with zero-length column names. (check-in: 791761ebac user: drh tags: trunk)
2015-11-14
22:04
Code simplification in sqlite3ColumnsFromExprList(). Update the %z format code so that it works with buffers obtained from sqlite3DbMalloc(). Add a testcase for the slow column name uniquifier. (check-in: 9272426057 user: drh tags: trunk)
20:52
Use a hash table to improve the preformance of column name uniqueness checking. (check-in: 5b08f29f45 user: drh tags: trunk)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/printf.c.
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    */
    width -= length;
    if( width>0 && !flag_leftjustify ) sqlite3AppendChar(pAccum, width, ' ');
    sqlite3StrAccumAppend(pAccum, bufpt, length);
    if( width>0 && flag_leftjustify ) sqlite3AppendChar(pAccum, width, ' ');

    if( zExtra ){
      sqlite3_free(zExtra);
      sqlite3DbFree(pAccum->db, zExtra);
      zExtra = 0;
    }
  }/* End for loop over the format string */
} /* End of function */

/*
** Enlarge the memory allocation on a StrAccum object so that it is
︙
Changes to src/select.c.
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  for(i=0, pCol=aCol; i<nCol && !db->mallocFailed; i++, pCol++){
    /* Get an appropriate name for the column
    */
    p = sqlite3ExprSkipCollate(pEList->a[i].pExpr);
    if( (zName = pEList->a[i].zName)!=0 ){
      /* If the column contains an "AS <name>" phrase, use <name> as the name */
      zName = sqlite3DbStrDup(db, zName);
    }else{
      Expr *pColExpr = p;  /* The expression that is the result column name */
      Table *pTab;         /* Table associated with this expression */
      while( pColExpr->op==TK_DOT ){
        pColExpr = pColExpr->pRight;
        assert( pColExpr!=0 );
      }
      if( pColExpr->op==TK_COLUMN && ALWAYS(pColExpr->pTab!=0) ){
        /* For columns use the column name name */
        int iCol = pColExpr->iColumn;
        pTab = pColExpr->pTab;
        if( iCol<0 ) iCol = pTab->iPKey;
        zName = sqlite3MPrintf(db, "%s",
                 iCol>=0 ? pTab->aCol[iCol].zName : "rowid");
        zName = iCol>=0 ? pTab->aCol[iCol].zName : "rowid";
      }else if( pColExpr->op==TK_ID ){
        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
        zName = sqlite3MPrintf(db, "%s", pColExpr->u.zToken);
        zName = pColExpr->u.zToken;
      }else{
        /* Use the original text of the column expression as its name */
        zName = sqlite3MPrintf(db, "%s", pEList->a[i].zSpan);
        zName = pEList->a[i].zSpan;
      }
    }
    zName = sqlite3MPrintf(db, "%s", zName);

    /* Make sure the column name is unique.  If the name is not unique,
    ** append an integer to the name so that it becomes unique.
    */
    cnt = 0;
    while( zName && sqlite3HashFind(&ht, zName)!=0 ){
      char *zNewName;
      nName = sqlite3Strlen30(zName);
      for(j=nName-1; j>0 && sqlite3Isdigit(zName[j]); j--){}
      if( zName[j]==':' ) nName = j;
      zName[nName] = 0;
      zNewName = sqlite3MPrintf(db, "%s:%u", zName, ++cnt);
      zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt);
      sqlite3DbFree(db, zName);
      zName = zNewName;
      if( cnt>3 ) sqlite3_randomness(sizeof(cnt), &cnt);
    }
    pCol->zName = zName;
    if( zName && sqlite3HashInsert(&ht, zName, pCol)==pCol ){
      db->mallocFailed = 1;
    }
  }
︙
Changes to test/misc1.test.
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# At one point, running this would read one byte passed the end of a 
# buffer, upsetting valgrind.
#
do_test misc1-24.0 {
  list [catch { sqlite3_prepare_v2 db ! -1 dummy } msg] $msg
} {1 {(1) unrecognized token: "!}}

# The following query (provided by Kostya Serebryany) used to take 25
# minutes to prepare.  This has been speeded up to about 250 milliseconds.
#
do_catchsql_test misc1-25.0 {
SELECT-1 UNION  SELECT 5 UNION SELECT 0 UNION SElECT*from(SELECT-5) UNION SELECT*from(SELECT-0) UNION  SELECT:SELECT-0 UNION SELECT-1 UNION SELECT 1 UNION SELECT 1 ORDER BY S  in(WITH K AS(WITH K AS(select'CREINDERcharREADEVIRTUL5TABLECONFLICT !1 USIN'' MFtOR(b38q,eWITH K AS(selectCREATe TABLE t0(a,b,c,d,e, PRIMARY KEY(a,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,b,c,d,c,a,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d'CEIl,k'',ab, g, a,b,o11b, i'nEX/charREDE IVT LR!VABLt5SG',N  ,N in rement,l_vacuum,M&U,'te3(''5l' a,bB,b,l*e)SELECT:SELECT, *,*,*from(( SELECT
$group,:conc ap0,1)fro,(select"",:PBAG,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,c,d,c,c,a,a,b,d,d,c,a,b,b,c,d,c,a,b,e,e,d,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d, foreign_keysc,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,a,b,d,d,c,a,b,b,c,d,c,a,b,e,e,d,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,c,d,c,a,b,d,d,c,a,a,b,d,d,c,a,b,b,c,d,c,a,b,e,e,d,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,a,b,d,d,c,a,b,b,c,d,c,a,b,e,e,d,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,c,a,b,b,c,d,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,d,c,e,d,d,c,a,b,b,c,c,a,b,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,bb,b,E,d,c,d,c,b,c,d,c,d,c,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,a,b,c,e,d,d,c,a,b,b,c,d,d,c,a,b,c,e,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,c,d,c,a,b,d,d,c,a,a,b,d,d,c,a,b,b,c,d,c,a,b,e,e,d,b,c,d,c,a,b,b,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,c,a,b,c,e,d,d,c,a,b,b,c,d,c,d,c,a,b,c,e,c,d,c,a,b,b,c,d,MAato_aecSELEC,+?b," "O,"i","a",""b  ,5 ))KEY)SELECT*FROM((k()reaC,k,K) eA,k '' )t ,K  M);
} {1 {too many columns in result set}}


finish_test