// ***************************************************************************
// Initialize the hash of tables in the descriptor.
// For every table in the JBBC list of the Hub as well as the extraHub,
// insert an entry into the hash table, using the table's name as the hash key.
// ***************************************************************************
void MVDetails::initTables(const QRJBBPtr jbb, CollHeap* heap)
{
// Map all the table names
// Start with the Hub tables.
const ElementPtrList& hubTables = jbb->getHub()->getJbbcList()->getList();
for (CollIndex i=0; i<hubTables.entries(); i++)
{
QRElementPtr element = hubTables[i];
// Ignore JBBCs that are not tables - they must be child-JBB references,
// so we will get to them when looping over the JBB list.
if (element->getElementType() == ET_Table)
{
const QRTablePtr table = element->downCastToQRTable();
const NAString& name = table->getTableName();
tableByNameHash_.insert(&name, table);
}
}
// Continue with the extra-hub tables.
const QRExtraHubPtr extraHub = jbb->getExtraHub();
if (extraHub != NULL)
{
QRTableListPtr extraHubTables = extraHub->getTableList();
if (extraHubTables != NULL)
{
for (CollIndex j=0; j<extraHubTables->entries(); j++)
{
QRTablePtr table = (*extraHubTables)[j];
const NAString& name = table->getTableName();
tableByNameHash_.insert(&name, table);
}
}
}
}
// ***************************************************************************
// ***************************************************************************
void MVDetails::addEqualitySet(QRJoinPredPtr joinPredElement,
NABoolean isFromExpr,
QROutputPtr output,
CollHeap* heap)
{
const ElementPtrList& equalitySet = joinPredElement->getEqualityList();
for (CollIndex i=0; i<equalitySet.entries(); i++)
{
const QRElementPtr halfPred = equalitySet[i];
// Now lets look at the equality set members
// Ignore members that are not simple columns.
if (halfPred->getElementType() != ET_Column)
continue;
const QRColumnPtr eqSetColumn = halfPred->getReferencedElement()->downCastToQRColumn();
// If this JoinPred element is a column of an LOJ table,
// skip it because it is not really equal to the others.
const QRElementPtr tableElem = getElementForID(eqSetColumn->getTableID());
if (tableElem->downCastToQRTable()->hasLOJParent())
continue;
// Compute the "ID Qualified" column name as the key.
const NAString* idQualifiedColName =
calcIDQualifiedColumnName(eqSetColumn->getTableID(), eqSetColumn->getColumnName(), heap);
// Insert into the hash table.
if (isFromExpr)
outputByInputColumns_.insert(idQualifiedColName, output);
else
outputByColumnName_.insert(idQualifiedColName, output);
}
} // MVDetails::addEqualitySet
// ***************************************************************************
// Get the table element (from the JBBC list) with this name (or NULL if not found).
// This method must NOT be used to find a specific table instance, because
// with self-joins, multiple tables have the same name.
// Use MVCandidate::getMvTableForQueryID() instead.
// ***************************************************************************
const QRTablePtr MVDetails::getTableFromName(const NAString& name)
{
QRElementPtr table = tableByNameHash_.getFirstValue(&name);
if (table == NULL)
return NULL;
return table->downCastToQRTable();
}
// ***************************************************************************
// Is this column from a table that has an LOJ parent?
// ***************************************************************************
NABoolean DescriptorDetails::isColumnFromLojTable(const QRColumnPtr col)
{
const NAString& tableID = col->getTableID();
const QRElementPtr tableElem = getElementForID(tableID);
assertLogAndThrow(CAT_MATCHTST_MVDETAILS, LL_MVQR_FAIL,
tableElem, QRLogicException,
"Table not found in JBB.");
const QRTablePtr table = tableElem->downCastToQRTable();
return table->hasLOJParent();
}
// ***************************************************************************
// ***************************************************************************
const NAString& DescriptorDetails::getTableNameFromColumn(QRColumnPtr colElem)
{
static const NAString empty("");
const NAString& tableID = colElem->getReferencedElement()->downCastToQRColumn()->getTableID();
const QRElementPtr tableElem = getElementForID(tableID);
if (tableElem==NULL)
{
// This table is in a JBB that was ommitted from the query descriptor.
// Return an empty table name.
return empty;
}
const QRTablePtr table = tableElem->downCastToQRTable();
return table->getTableName();
}
// ***************************************************************************
// ***************************************************************************
void JBBDetails::initBaseTables(CollHeap* heap)
{
// Create BaseTableDetails objects for the JBB hub tables.
const ElementPtrList& hubTables = jbbDesc_->getHub()->getJbbcList()->getList();
for (CollIndex i=0; i<hubTables.entries(); i++)
{
const QRElementPtr jbbc = hubTables[i];
if (jbbc->getElementType() != ET_Table)
continue; // Skip reference to other JBBs.
const QRTablePtr table = jbbc->downCastToQRTable();
if (table->hasLOJParent())
hasLOJs_ = TRUE;
// Rest of the stuff only needed for MVs.
if (!isAnMV_)
continue;
BaseTableDetailsPtr tableDetails = new(heap)
BaseTableDetails(table, TRUE, ADD_MEMCHECK_ARGS(heap));
baseTablesByID_.insert(&tableDetails->getID(), tableDetails);
}
// Now do the same for the extra-hub tables.
const QRTableListPtr extraHubTables = jbbDesc_->getExtraHub()->getTableList();
if (extraHubTables != NULL)
{
for (CollIndex j=0; j<extraHubTables->entries(); j++)
{
const QRTablePtr table = (*extraHubTables)[j];
if (table->hasLOJParent())
hasLOJs_ = TRUE;
// Rest of the stuff only needed for MVs.
if (!isAnMV_)
continue;
BaseTableDetailsPtr tableDetails = new(heap)
BaseTableDetails(table, FALSE, ADD_MEMCHECK_ARGS(heap));
baseTablesByID_.insert(&tableDetails->getID(), tableDetails);
}
}
}
// ***************************************************************************
// Initialize the several hash tables that map output list elements:
// outputByIDHash_ - Using the ID of the output item as the key.
// outputByColumnName_ - Using the "ID Qualified" column name as the key.
// outputByExprText_ - Using the expression text as the key.
// outputByInputColumns_ - Using the name of expression input column as the key.
// ***************************************************************************
void MVDetails::initOutputs(const QRJBBPtr jbb, CollHeap* heap)
{
// Match the output elements with their names.
const QROutputListPtr outputList = jbb->getOutputList();
assertLogAndThrow(CAT_MATCHTST_MVDETAILS, LL_MVQR_FAIL,
outputList != NULL, QRLogicException,
"Output list is null.");
// For each output list element
for (CollIndex i=0; i<outputList->entries(); i++)
{
QROutputPtr output = (*outputList)[i];
// Set the ordinal number of the output element.
output->setColPos(i+1);
// Get the output item (column or expression).
QRElementPtr outputItem = output->getOutputItem()->getReferencedElement();
const NAString& id = outputItem->getID();
// Insert the ID of the output item (whatever it is) into the ID hash.
outputByIDHash_.insert(&id, output);
// OK, now lets check what type of output item it is.
switch (outputItem->getElementType())
{
case ET_Column:
{
// If its an output column, add it to the output column by name hash.
const QRColumnPtr col = outputItem->downCastToQRColumn();
const QRElementPtr tableElem = getElementForID(col->getTableID());
NABoolean hasLOJParent = tableElem->downCastToQRTable()->hasLOJParent();
if (!isFromJoin(col) || hasLOJParent)
{
// Compute the "ID Qualified" column name as the key.
const NAString* idQualifiedColName =
calcIDQualifiedColumnName(col->getTableID(), col->getColumnName(), heap);
// Insert into the hash table.
outputByColumnName_.insert(idQualifiedColName, output);
}
else
{
// If its an equality set, insert all the participating columns
// as pointing to the same MV output column.
const QRJoinPredPtr jp = getJoinPred(col);
const QRJoinPredPtr joinPredElement = jp->downCastToQRJoinPred();
addEqualitySet(joinPredElement, FALSE, output, heap);
}
break;
}
case ET_JoinPred:
{
assertLogAndThrow(CAT_MATCHTST_MVDETAILS, LL_MVQR_FAIL,
(outputItem->getElementType() == ET_JoinPred), QRLogicException,
"Unexpected JoinPred element.");
// If its an equality set, insert all the participating columns
// as pointing to the same MV output column.
const QRJoinPredPtr joinPredElement = outputItem->downCastToQRJoinPred();
addEqualitySet(joinPredElement, FALSE, output, heap);
break;
}
case ET_Expr:
{
// This is an expression. Insert the expression text into the expression hash.
const QRExprPtr expr = outputItem->downCastToQRExpr();
const NAString& exprText = expr->getExprText();
outputByExprText_.insert(&exprText, output);
QRLogger::log(CAT_MATCHTST_MVDETAILS, LL_DEBUG,
"Adding output expression: %s.", exprText.data());
// Also map the expressions's input columns to it.
// This call to getInitColumns() also inits the input list using the
// right heap.
const ElementPtrList& inputs = expr->getInputColumns(heap);
if (inputs.entries() > 0)
{
for (CollIndex j=0; j<inputs.entries(); j++)
{
QRElementPtr inputElem = inputs[j]->getReferencedElement();
if (inputElem->getElementType() == ET_Column)
{
QRColumnPtr inputCol = inputElem->downCastToQRColumn();
// Compute the "ID Qualified" column name as the key.
const NAString* idQualifiedColName =
calcIDQualifiedColumnName(inputCol->getTableID(), inputCol->getColumnName(), heap);
outputByInputColumns_.insert(idQualifiedColName, output);
}
else
{
QRJoinPredPtr inputJoinPred = inputElem->downCastToQRJoinPred();
addEqualitySet(inputJoinPred, TRUE, output, heap);
}
}
}
// Check if this is the COUNT(*) function.
QRExplicitExprPtr rootExpr = expr->getExprRoot();
if (rootExpr->getElementType() == ET_Function)
{
QRFunctionPtr func = rootExpr->downCastToQRFunction();
if (func->getAggregateFunc() == QRFunction::AFT_COUNTSTAR)
{
// Found it, now remember it for later use.
// If a COUNT(*) equivalent function has already been found
// (see below) - overwrite it.
countStar_ = output;
}
else if (countStar_ == NULL &&
func->isCountStarEquivalent(heap) )
{
// Well, we didn't find a COUNT(*) yet, but we found a COUNT(a)
// and the input column is NOT NOLL, we can use it as a COUNT(*) column.
countStar_ = output;
}
}
} // end of case ET_Expr
break;
} // switch on element type
} // for on output list elements
} // MVDetails::initOutputs()
