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Overview
Comment:Make the implementation of the sqlite3_aggregate_context() interface faster for second an subsequent invocations. This helps all aggregate functions to perform better.
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SHA1: 802148f3110462eac939d53ce08eb9a2f6aac739
User & Date: drh 2014-08-23 18:17:19.059
Context
2014-08-23
19:04
Changes to sqlite3ScratchMalloc() that make the entire memory allocation interface a little faster and about 100 bytes smaller. (check-in: f83daa16f6 user: drh tags: trunk)
18:17
Make the implementation of the sqlite3_aggregate_context() interface faster for second an subsequent invocations. This helps all aggregate functions to perform better. (check-in: 802148f311 user: drh tags: trunk)
17:41
Improved performance in the type handling of arithmetic operators in the VDBE. (check-in: 0c0a603950 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/vdbeapi.c.
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  char *zErr;
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  zErr = sqlite3_mprintf(
      "unable to use function %s in the requested context", zName);
  sqlite3_result_error(context, zErr, -1);
  sqlite3_free(zErr);
}























/*
** Allocate or return the aggregate context for a user function.  A new
** context is allocated on the first call.  Subsequent calls return the
** same context that was returned on prior calls.
*/
void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
  Mem *pMem;
  assert( p && p->pFunc && p->pFunc->xStep );
  assert( sqlite3_mutex_held(p->s.db->mutex) );
  pMem = p->pMem;
  testcase( nByte<0 );
  if( (pMem->flags & MEM_Agg)==0 ){
    if( nByte<=0 ){
      sqlite3VdbeMemReleaseExternal(pMem);
      pMem->flags = MEM_Null;
      pMem->z = 0;
    }else{
      sqlite3VdbeMemGrow(pMem, nByte, 0);
      pMem->flags = MEM_Agg;
      pMem->u.pDef = p->pFunc;
      if( pMem->z ){
        memset(pMem->z, 0, nByte);
      }
    }
  }
  return (void*)pMem->z;
}

/*
** Return the auxilary data pointer, if any, for the iArg'th argument to
** the user-function defined by pCtx.
*/
void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){







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  char *zErr;
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  zErr = sqlite3_mprintf(
      "unable to use function %s in the requested context", zName);
  sqlite3_result_error(context, zErr, -1);
  sqlite3_free(zErr);
}

/*
** Create a new aggregate context for p and return a pointer to
** its pMem->z element.
*/
static SQLITE_NOINLINE void *createAggContext(sqlite3_context *p, int nByte){
  Mem *pMem = p->pMem;
  assert( (pMem->flags & MEM_Agg)==0 );
  if( nByte<=0 ){
    sqlite3VdbeMemReleaseExternal(pMem);
    pMem->flags = MEM_Null;
    pMem->z = 0;
  }else{
    sqlite3VdbeMemGrow(pMem, nByte, 0);
    pMem->flags = MEM_Agg;
    pMem->u.pDef = p->pFunc;
    if( pMem->z ){
      memset(pMem->z, 0, nByte);
    }
  }
  return (void*)pMem->z;
}

/*
** Allocate or return the aggregate context for a user function.  A new
** context is allocated on the first call.  Subsequent calls return the
** same context that was returned on prior calls.
*/
void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){

  assert( p && p->pFunc && p->pFunc->xStep );
  assert( sqlite3_mutex_held(p->s.db->mutex) );

  testcase( nByte<0 );
  if( (p->pMem->flags & MEM_Agg)==0 ){
    return createAggContext(p, nByte);



  }else{



    return (void*)p->pMem->z;

  }



}

/*
** Return the auxilary data pointer, if any, for the iArg'th argument to
** the user-function defined by pCtx.
*/
void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){