private void INTERNAL_segmentWalkForNextKey(
IComparable<RecordKey> startkeytest,
bool direction_is_forward,
ISortedSegment curseg_raw,
RangeKey curseg_rangekey,
IScannableDictionary<RecordKey, RecordData> handledIndexRecords,
int maxgen,
IScannableDictionary<RecordKey, RecordData> recordsBeingAssembled,
bool equal_ok,
SegmentWalkStats stats)
{
// TODO: convert all ISortedSegments to be IScannable
IScannable<RecordKey, RecordUpdate> curseg = (IScannable<RecordKey, RecordUpdate>)curseg_raw;
stats.segmentWalkInvocations++;
// first look in this segment for a next-key **IF** it may contain one
if (curseg_rangekey.directlyContainsKey(startkeytest)) {
// we need to keep looking until we find a live record, as we need all the deletion tombstones
// between startkey and the next live record.
IEnumerable<KeyValuePair<RecordKey, RecordUpdate>> seg_scanner;
if (direction_is_forward) {
seg_scanner = curseg.scanForward(
new ScanRange<RecordKey>(
startkeytest,
new ScanRange<RecordKey>.maxKey(),
null));
} else {
seg_scanner = curseg.scanBackward(
new ScanRange<RecordKey>(
new ScanRange<RecordKey>.minKey(),
startkeytest,
null));
}
foreach (var kvp in seg_scanner) {
if (!equal_ok) { // have ">" test vs ">="
if (startkeytest.CompareTo(kvp.Key) == 0) {
continue;
}
}
RecordData partial_record;
stats.rowAccumulate_TryGet++;
if (!recordsBeingAssembled.TryGetValue(kvp.Key, out partial_record)) {
partial_record = new RecordData(RecordDataState.NOT_PROVIDED, kvp.Key);
recordsBeingAssembled[kvp.Key] = partial_record;
} else {
stats.rowDuplicatesAppeared++;
}
partial_record.applyUpdate(kvp.Value);
stats.rowUpdatesApplied++;
#if DEBUG_SEGMENT_ACCUMULATION
for (int depth = 10; depth > maxgen; depth--) { Console.Write(" "); }
Console.WriteLine("accumulated update: {0}", kvp);
#endif
if (partial_record.State != RecordDataState.DELETED) {
// we accumulated to at least one live record, so stop adding potential records
break;
}
}
}
// find all generation range references that are relevant for this key
// .. make a note of which ones are "current"
if (curseg_rangekey.directlyContainsKey(GEN_KEY_PREFIX)) {
BDSkipList<RecordKey, RecordUpdate> todo_list = new BDSkipList<RecordKey, RecordUpdate>();
for (int i = maxgen - 1; i >= 0; i--) {
stats.segmentRangeRowScansPerformed++;
foreach (KeyValuePair<RecordKey, RecordUpdate> rangerow in RangeKey.findAllEligibleRangeRows(curseg, startkeytest, i, stats)) {
// see if it is new for our handledIndexRecords dataset
RecordData partial_rangedata;
stats.segmentAccumulate_TryGet++;
if (!handledIndexRecords.TryGetValue(rangerow.Key, out partial_rangedata)) {
partial_rangedata = new RecordData(RecordDataState.NOT_PROVIDED, rangerow.Key);
handledIndexRecords[rangerow.Key] = partial_rangedata;
}
if ((partial_rangedata.State == RecordDataState.INCOMPLETE) ||
(partial_rangedata.State == RecordDataState.NOT_PROVIDED)) {
// we're suppilying new data for this index record
partial_rangedata.applyUpdate(rangerow.Value);
stats.segmentUpdatesApplied++;
// because we're suppilying new data, we should add this to our
// private TODO list if it is a FULL update, NOT a tombstone
if (rangerow.Value.type == RecordUpdateTypes.FULL) {
#if DEBUG_SEGMENT_RANGE_WALK
for (int depth = 10; depth > maxgen; depth--) { Console.Write(" "); }
Console.WriteLine("adding SegmentRangeRow: {0}", rangerow);
#endif
todo_list.Add(rangerow);
}
}
}
}
// now repeat the walk through our todo list:
foreach (KeyValuePair<RecordKey, RecordUpdate> rangepointer in todo_list.scanBackward(null)) {
if (rangepointer.Value.type == RecordUpdateTypes.DELETION_TOMBSTONE) {
// skip deletion tombstones
stats.segmentDeletionTombstonesSkipped++;
continue;
}
SegmentReader next_seg = segmentReaderFromRow(rangepointer);
RangeKey next_seg_rangekey = RangeKey.decodeFromRecordKey(rangepointer.Key);
#if DEBUG_SEGMENT_WALK
for (int depth = 10; depth > maxgen; depth--) { Console.Write(" "); }
Console.WriteLine("..WalkForNextKey descending to: {0}", rangepointer);
#endif
// RECURSE
INTERNAL_segmentWalkForNextKey(
startkeytest,
direction_is_forward,
next_seg,
next_seg_rangekey,
handledIndexRecords,
maxgen - 1,
recordsBeingAssembled,
equal_ok,
stats);
}
// now repeat the walk of range references in this segment, this time actually descending
}
}
private void INTERNAL_segmentWalkCursorSetupForNextKey(
IComparable<RecordKey> startkeytest,
bool direction_is_forward,
ISortedSegment curseg_raw,
RangeKey curseg_rangekey,
IScannableDictionary<RecordKey, RecordData> handledIndexRecords,
int maxgen,
IScannableDictionary<RangeKey, IScannable<RecordKey, RecordUpdate>> segmentsWithRecords,
bool equal_ok,
SegmentWalkStats stats)
{
// TODO: convert all ISortedSegments to be IScannable
IScannable<RecordKey, RecordUpdate> curseg = (IScannable<RecordKey, RecordUpdate>)curseg_raw;
stats.segmentWalkInvocations++;
// first look in this segment for a next-key **IF** it may contain one
if (curseg_rangekey.directlyContainsKey(startkeytest)) {
// add the current segment to the list of segments with records.
segmentsWithRecords.Add(curseg_rangekey,curseg);
}
// find all generation range references that are relevant for this key
// .. make a note of which ones are "current"
if (curseg_rangekey.directlyContainsKey(GEN_KEY_PREFIX)) {
BDSkipList<RecordKey, RecordUpdate> todo_list = new BDSkipList<RecordKey, RecordUpdate>();
if (curseg_rangekey.generation > stats.handlingGeneration) {
throw new Exception("cursor segup generation priority inversion");
}
stats.handlingGeneration = curseg_rangekey.generation;
for (int i = maxgen - 1; i >= 0; i--) {
stats.segmentRangeRowScansPerformed++;
foreach (KeyValuePair<RecordKey, RecordUpdate> rangerow in RangeKey.findAllEligibleRangeRows(curseg, startkeytest, i, stats)) {
// see if it is new for our handledIndexRecords dataset
RecordData partial_rangedata;
stats.segmentAccumulate_TryGet++;
if (!handledIndexRecords.TryGetValue(rangerow.Key, out partial_rangedata)) {
partial_rangedata = new RecordData(RecordDataState.NOT_PROVIDED, rangerow.Key);
handledIndexRecords[rangerow.Key] = partial_rangedata;
}
if ((partial_rangedata.State == RecordDataState.INCOMPLETE) ||
(partial_rangedata.State == RecordDataState.NOT_PROVIDED)) {
// we're suppilying new data for this index record
partial_rangedata.applyUpdate(rangerow.Value);
stats.segmentUpdatesApplied++;
// because we're suppilying new data, we should add this to our
// private TODO list if it is a FULL update, NOT a tombstone
if (rangerow.Value.type == RecordUpdateTypes.FULL) {
#if DEBUG_SEGMENT_RANGE_WALK
for (int depth = 10; depth > maxgen; depth--) { Console.Write(" "); }
Console.WriteLine("adding SegmentRangeRow: {0}", rangerow);
#endif
todo_list.Add(rangerow);
}
}
}
}
// now repeat the walk through our todo list:
foreach (KeyValuePair<RecordKey, RecordUpdate> rangepointer in todo_list.scanBackward(null)) {
if (rangepointer.Value.type == RecordUpdateTypes.DELETION_TOMBSTONE) {
// skip deletion tombstones
stats.segmentDeletionTombstonesSkipped++;
continue;
}
SegmentReader next_seg = segmentReaderFromRow(rangepointer);
RangeKey next_seg_rangekey = RangeKey.decodeFromRecordKey(rangepointer.Key);
#if DEBUG_SEGMENT_WALK
for (int depth = 10; depth > maxgen; depth--) { Console.Write(" "); }
Console.WriteLine("..WalkForNextKey descending to: {0}", rangepointer);
#endif
// RECURSE
INTERNAL_segmentWalkCursorSetupForNextKey(
startkeytest,
direction_is_forward,
next_seg,
next_seg_rangekey,
handledIndexRecords,
maxgen - 1,
segmentsWithRecords,
equal_ok,
stats);
}
// now repeat the walk of range references in this segment, this time actually descending
}
}