// computeHistoryBuffer
//
// Helper function that traverses the set of root sequence functions
// supplied by the compiler and dynamically determines the size
// of the history buffer.
//
void PhysSequence::computeHistoryRows(const ValueIdSet &sequenceFunctions,//historyIds
Lng32 &computedHistoryRows,
Lng32 &unableToCalculate,
NABoolean &unboundedFollowing,
Lng32 &minFollowingRows,
const ValueIdSet &outputFromChild)
{
ValueIdSet children;
ValueIdSet historyAttributes;
Lng32 value = 0;
for(ValueId valId = sequenceFunctions.init();
sequenceFunctions.next(valId);
sequenceFunctions.advance(valId))
{
if(valId.getItemExpr()->isASequenceFunction())
{
ItemExpr *itmExpr = valId.getItemExpr();
switch(itmExpr->getOperatorType())
{
// THIS and NOT THIS are not dynamically computed
//
case ITM_THIS:
case ITM_NOT_THIS:
break;
// The RUNNING functions and LastNotNull all need to go back just one row.
//
case ITM_RUNNING_SUM:
case ITM_RUNNING_COUNT:
case ITM_RUNNING_MIN:
case ITM_RUNNING_MAX:
case ITM_RUNNING_CHANGE:
case ITM_LAST_NOT_NULL:
computedHistoryRows = MAXOF(computedHistoryRows, 2);
break;
///set to unable to compute for now-- will change later to compte values from frameStart_ and frameEnd_
case ITM_OLAP_SUM:
case ITM_OLAP_COUNT:
case ITM_OLAP_MIN:
case ITM_OLAP_MAX:
case ITM_OLAP_RANK:
case ITM_OLAP_DRANK:
{
if ( !outputFromChild.contains(itmExpr->getValueId()))
{
ItmSeqOlapFunction * olap = (ItmSeqOlapFunction*)itmExpr;
if (olap->isFrameStartUnboundedPreceding()) //(olap->getframeStart() == - INT_MAX)
{
computedHistoryRows = MAXOF(computedHistoryRows, 2);
}
else
{
computedHistoryRows = MAXOF(computedHistoryRows, ABS(olap->getframeStart()) + 2);
}
if (!olap->isFrameEndUnboundedFollowing()) //(olap->getframeEnd() != INT_MAX)
{
computedHistoryRows = MAXOF(computedHistoryRows, ABS(olap->getframeEnd()) + 1);
}
if (olap->isFrameEndUnboundedFollowing()) //(olap->getframeEnd() == INT_MAX)
{
unboundedFollowing = TRUE;
if (olap->getframeStart() > 0)
{
minFollowingRows = ((minFollowingRows > olap->getframeStart()) ?
minFollowingRows : olap->getframeStart());
}
} else if (olap->getframeEnd() > 0)
{
minFollowingRows = ((minFollowingRows > olap->getframeEnd()) ?
minFollowingRows : olap->getframeEnd());
}
}
}
break;
// If 'rows since', we cannot determine how much history is needed.
case ITM_ROWS_SINCE:
unableToCalculate = 1;
break;
// The MOVING and OFFSET functions need to go back as far as the value
// of their second child.
//
// The second argument can be:
// Constant: for these, we can use the constant value to set the upper bound
// for the history buffer.
// ItmScalarMinMax(child0, child1) (with operType = ITM_SCALAR_MIN)
// - if child0 or child1 is a constant, then we can use either one
// to set the upper bound.
case ITM_MOVING_MIN:
case ITM_MOVING_MAX:
case ITM_OFFSET:
for(Lng32 i = 1; i < itmExpr->getArity(); i++)
{
if (itmExpr->child(i)->getOperatorType() != ITM_NOTCOVERED)
{
ItemExpr * exprPtr = itmExpr->child(i);
NABoolean negate;
ConstValue *cv = exprPtr->castToConstValue(negate);
if (cv AND cv->canGetExactNumericValue())
{
Lng32 scale;
Int64 value64 = cv->getExactNumericValue(scale);
if(scale == 0 && value64 >= 0 && value64 < INT_MAX)
{
value64 = (negate ? -value64 : value64);
value = MAXOF((Lng32)value64, value);
}
}
else
{
if (exprPtr->getOperatorType() == ITM_SCALAR_MIN)
{
for(Lng32 j = 0; j < exprPtr->getArity(); j++)
{
if (exprPtr->child(j)->getOperatorType()
!= ITM_NOTCOVERED)
{
ItemExpr * exprPtr1 = exprPtr->child(j);
NABoolean negate1;
ConstValue *cv1 = exprPtr1->castToConstValue(negate1);
if (cv1 AND cv1->canGetExactNumericValue())
{
Lng32 scale1;
Int64 value64_1 = cv1->getExactNumericValue(scale1);
if(scale1 == 0 && value64_1 >= 0 && value64_1 < INT_MAX)
{
value64_1 = (negate1 ? -value64_1 : value64_1);
value = MAXOF((Lng32)value64_1, value);
}
}
}
}
}
} // end of inner else
}// end of if
}// end of for
// Check if the value is greater than zero.
// If it is, then save the value, but first
// increment the returned ConstValue by one.
// Otherwise, the offset or moving value was unable
// to be calculated.
if (value > 0)
{
value++;
computedHistoryRows = MAXOF(computedHistoryRows, value);
value = 0;
}
else
unableToCalculate = 1;
break;
default:
CMPASSERT(0);
}
}
// Gather all the children, and if not empty, recurse down to the
// next level of the tree.
//
for(Lng32 i = 0; i < valId.getItemExpr()->getArity(); i++) {
if (//valId.getItemExpr()->child(i)->getOperatorType() != ITM_NOTCOVERED //old stuff
!outputFromChild.contains(valId.getItemExpr()->child(i)->getValueId()))
{
children += valId.getItemExpr()->child(i)->getValueId();
}
}
}
if (NOT children.isEmpty())
{
computeHistoryRows(children,
computedHistoryRows,
unableToCalculate,
unboundedFollowing,
minFollowingRows,
outputFromChild);
}
} // PhysSequence::computeHistoryRows
