/// <summary>Does the actual (time-consuming) work of the merge,
/// but without holding synchronized lock on IndexWriter
/// instance
/// </summary>
private int MergeMiddle(MergePolicy.OneMerge merge)
{
merge.CheckAborted(directory);
System.String mergedName = merge.info.name;
SegmentMerger merger = null;
int mergedDocCount = 0;
SegmentInfos sourceSegments = merge.segments;
int numSegments = sourceSegments.Count;
if (infoStream != null)
Message("merging " + merge.SegString(directory));
merger = new SegmentMerger(this, mergedName, merge);
merge.readers = new SegmentReader[numSegments];
merge.readersClone = new SegmentReader[numSegments];
bool mergeDocStores = false;
System.Collections.Hashtable dss = new System.Collections.Hashtable();
String currentDocStoreSegment;
lock(this) {
currentDocStoreSegment = docWriter.GetDocStoreSegment();
}
bool currentDSSMerged = false;
// This is try/finally to make sure merger's readers are
// closed:
bool success = false;
try
{
int totDocCount = 0;
for (int i = 0; i < numSegments; i++)
{
SegmentInfo info = sourceSegments.Info(i);
// Hold onto the "live" reader; we will use this to
// commit merged deletes
SegmentReader reader = merge.readers[i] = readerPool.Get(info, merge.mergeDocStores, MERGE_READ_BUFFER_SIZE, -1);
// We clone the segment readers because other
// deletes may come in while we're merging so we
// need readers that will not change
SegmentReader clone = merge.readersClone[i] = (SegmentReader)reader.Clone(true);
merger.Add(clone);
if (clone.HasDeletions())
{
mergeDocStores = true;
}
if (info.GetDocStoreOffset() != -1 && currentDocStoreSegment != null)
{
currentDSSMerged |= currentDocStoreSegment.Equals(info.GetDocStoreSegment());
}
totDocCount += clone.NumDocs();
}
if (infoStream != null)
{
Message("merge: total " + totDocCount + " docs");
}
merge.CheckAborted(directory);
// If deletions have arrived and it has now become
// necessary to merge doc stores, go and open them:
if (mergeDocStores && !merge.mergeDocStores)
{
merge.mergeDocStores = true;
lock (this)
{
if (currentDSSMerged)
{
if (infoStream != null)
{
Message("now flush at mergeMiddle");
}
DoFlush(true, false);
}
}
for (int i = 0; i < numSegments; i++)
{
merge.readersClone[i].OpenDocStores();
}
// Clear DSS
merge.info.SetDocStore(-1, null, false);
}
// This is where all the work happens:
mergedDocCount = merge.info.docCount = merger.Merge(merge.mergeDocStores);
System.Diagnostics.Debug.Assert(mergedDocCount == totDocCount);
if (merge.useCompoundFile)
{
success = false;
string compoundFileName = IndexFileNames.SegmentFileName(mergedName, IndexFileNames.COMPOUND_FILE_EXTENSION);
try
{
if (infoStream != null)
{
Message("create compound file " + compoundFileName);
}
merger.CreateCompoundFile(compoundFileName);
success = true;
}
catch (System.IO.IOException ioe)
{
lock (this)
{
if (merge.IsAborted())
{
// This can happen if rollback or close(false)
// is called -- fall through to logic below to
// remove the partially created CFS:
}
else
{
HandleMergeException(ioe, merge);
}
}
}
catch (Exception t)
{
HandleMergeException(t, merge);
}
finally
{
if (!success)
{
if (infoStream != null)
{
Message("hit exception creating compound file during merge");
}
lock (this)
{
deleter.DeleteFile(compoundFileName);
deleter.DeleteNewFiles(merger.GetMergedFiles());
}
}
}
success = false;
lock (this)
{
// delete new non cfs files directly: they were never
// registered with IFD
deleter.DeleteNewFiles(merger.GetMergedFiles());
if (merge.IsAborted())
{
if (infoStream != null)
{
Message("abort merge after building CFS");
}
deleter.DeleteFile(compoundFileName);
return 0;
}
}
merge.info.SetUseCompoundFile(true);
}
int termsIndexDivisor;
bool loadDocStores;
// if the merged segment warmer was not installed when
// this merge was started, causing us to not force
// the docStores to close, we can't warm it now
bool canWarm = merge.info.GetDocStoreSegment() == null || currentDocStoreSegment == null || !merge.info.GetDocStoreSegment().Equals(currentDocStoreSegment);
if (poolReaders && mergedSegmentWarmer != null && canWarm)
{
// Load terms index & doc stores so the segment
// warmer can run searches, load documents/term
// vectors
termsIndexDivisor = readerTermsIndexDivisor;
loadDocStores = true;
}
else
{
termsIndexDivisor = -1;
loadDocStores = false;
}
// TODO: in the non-realtime case, we may want to only
// keep deletes (it's costly to open entire reader
// when we just need deletes)
SegmentReader mergedReader = readerPool.Get(merge.info, loadDocStores, BufferedIndexInput.BUFFER_SIZE, termsIndexDivisor);
try
{
if (poolReaders && mergedSegmentWarmer != null)
{
mergedSegmentWarmer.Warm(mergedReader);
}
if (!CommitMerge(merge, merger, mergedDocCount, mergedReader))
{
// commitMerge will return false if this merge was aborted
return 0;
}
}
finally
{
lock (this)
{
readerPool.Release(mergedReader);
}
}
success = true;
}
finally
{
// Readers are already closed in commitMerge if we didn't hit
// an exc:
if (!success)
{
CloseMergeReaders(merge, true);
}
}
merge.mergeDone = true;
lock (mergeScheduler)
{
System.Threading.Monitor.PulseAll(mergeScheduler);
}
// Force a sync after commiting the merge. Once this
// sync completes then all index files referenced by the
// current segmentInfos are on stable storage so if the
// OS/machine crashes, or power cord is yanked, the
// index will be intact. Note that this is just one
// (somewhat arbitrary) policy; we could try other
// policies like only sync if it's been > X minutes or
// more than Y bytes have been written, etc.
if (autoCommit)
{
long size;
lock (this)
{
size = merge.info.SizeInBytes();
}
Commit(size);
}
return mergedDocCount;
}