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Overview
Comment:Performance optimization the Vdbe allocator.
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SHA1: e2c4995bf1099cc02bcb1dc4a4631f06a870d171
User & Date: drh 2016-04-12 00:26:59.031
Context
2016-04-12
11:58
Update the header comment on the memjournal.c file. No code changes. (check-in: 07f10deabb user: drh tags: trunk)
00:26
Performance optimization the Vdbe allocator. (check-in: e2c4995bf1 user: drh tags: trunk)
00:16
Avoid unnecessary calls to object destructors for a small performance gain. (check-in: aec94b6ee6 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/select.c.
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  return pTab;
}

/*
** Get a VDBE for the given parser context.  Create a new one if necessary.
** If an error occurs, return NULL and leave a message in pParse.
*/
Vdbe *sqlite3GetVdbe(Parse *pParse){
  Vdbe *v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqlite3VdbeCreate(pParse);
    if( v ) sqlite3VdbeAddOp0(v, OP_Init);
    if( pParse->pToplevel==0
     && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst)
    ){
      pParse->okConstFactor = 1;
    }

  }


  return v;
}


/*
** Compute the iLimit and iOffset fields of the SELECT based on the
** pLimit and pOffset expressions.  pLimit and pOffset hold the expressions
** that appear in the original SQL statement after the LIMIT and OFFSET








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  return pTab;
}

/*
** Get a VDBE for the given parser context.  Create a new one if necessary.
** If an error occurs, return NULL and leave a message in pParse.
*/
static SQLITE_NOINLINE Vdbe *allocVdbe(Parse *pParse){


  Vdbe *v = pParse->pVdbe = sqlite3VdbeCreate(pParse);
  if( v ) sqlite3VdbeAddOp0(v, OP_Init);
  if( pParse->pToplevel==0
   && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst)
  ){
    pParse->okConstFactor = 1;
  }
  return v;
}
Vdbe *sqlite3GetVdbe(Parse *pParse){
  Vdbe *v = pParse->pVdbe;
  return v ? v : allocVdbe(pParse);
}


/*
** Compute the iLimit and iOffset fields of the SELECT based on the
** pLimit and pOffset expressions.  pLimit and pOffset hold the expressions
** that appear in the original SQL statement after the LIMIT and OFFSET
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