public bool next(RecordIdentifier recordIdentifier,
OrcStruct prev)
{
bool keysSame = true;
while (keysSame && primary != null)
{
// The primary's nextRecord is the next value to return
OrcStruct current = primary.nextRecord;
recordIdentifier.set(primary.key);
// Advance the primary reader to the next record
primary.next(extraValue);
// Save the current record as the new extraValue for next time so that
// we minimize allocations
extraValue = current;
// now that the primary reader has advanced, we need to see if we
// continue to read it or move to the secondary.
if (primary.nextRecord == null ||
primary.key.compareTo(secondaryKey) > 0)
{
// if the primary isn't done, push it back into the readers
if (primary.nextRecord != null)
{
readers.put(primary.key, primary);
}
// update primary and secondaryKey
Map.Entry <ReaderKey, ReaderPair> entry = readers.pollFirstEntry();
if (entry != null)
{
primary = entry.getValue();
if (readers.isEmpty())
{
secondaryKey = null;
}
else
{
secondaryKey = readers.firstKey();
}
}
else
{
primary = null;
}
}
// if this transaction isn't ok, skip over it
if (!validTxnList.isTxnValid(
((ReaderKey)recordIdentifier).getCurrentTransactionId()))
{
continue;
}
/*for multi-statement txns, you may have multiple events for the same
* row in the same (current) transaction. We want to collapse these to just the last one
* regardless whether we are minor compacting. Consider INSERT/UPDATE/UPDATE of the
* same row in the same txn. There is no benefit passing along anything except the last
* event. If we did want to pass it along, we'd have to include statementId in the row
* returned so that compaction could write it out or make minor minor compaction understand
* how to write out delta files in delta_xxx_yyy_stid format. There doesn't seem to be any
* value in this.*/
bool isSameRow = prevKey.isSameRow((ReaderKey)recordIdentifier);
// if we are collapsing, figure out if this is a new row
if (collapse || isSameRow)
{
keysSame = (collapse && prevKey.compareRow(recordIdentifier) == 0) || (isSameRow);
if (!keysSame)
{
prevKey.set(recordIdentifier);
}
}
else
{
keysSame = false;
}
// set the output record by fiddling with the pointers so that we can
// avoid a copy.
prev.linkFields(current);
}
return(!keysSame);
}
