/// <summary>Checks if any merges are now necessary and returns a
/// {@link MergePolicy.MergeSpecification} if so. A merge
/// is necessary when there are more than {@link
/// #setMergeFactor} segments at a given level. When
/// multiple levels have too many segments, this method
/// will return multiple merges, allowing the {@link
/// MergeScheduler} to use concurrency.
/// </summary>
public override MergeSpecification FindMerges(SegmentInfos infos)
{
int numSegments = infos.Count;
if (Verbose())
{
Message("findMerges: " + numSegments + " segments");
}
// Compute levels, which is just log (base mergeFactor)
// of the size of each segment
float[] levels = new float[numSegments];
float norm = (float)System.Math.Log(mergeFactor);
for (int i = 0; i < numSegments; i++)
{
SegmentInfo info = infos.Info(i);
long size = Size(info);
// Floor tiny segments
if (size < 1)
{
size = 1;
}
levels[i] = (float)System.Math.Log(size) / norm;
}
float levelFloor;
if (minMergeSize <= 0)
{
levelFloor = (float)0.0;
}
else
{
levelFloor = (float)(System.Math.Log(minMergeSize) / norm);
}
// Now, we quantize the log values into levels. The
// first level is any segment whose log size is within
// LEVEL_LOG_SPAN of the max size, or, who has such as
// segment "to the right". Then, we find the max of all
// other segments and use that to define the next level
// segment, etc.
MergeSpecification spec = null;
int start = 0;
while (start < numSegments)
{
// Find max level of all segments not already
// quantized.
float maxLevel = levels[start];
for (int i = 1 + start; i < numSegments; i++)
{
float level = levels[i];
if (level > maxLevel)
{
maxLevel = level;
}
}
// Now search backwards for the rightmost segment that
// falls into this level:
float levelBottom;
if (maxLevel < levelFloor)
{
// All remaining segments fall into the min level
levelBottom = -1.0F;
}
else
{
levelBottom = (float)(maxLevel - LEVEL_LOG_SPAN);
// Force a boundary at the level floor
if (levelBottom < levelFloor && maxLevel >= levelFloor)
{
levelBottom = levelFloor;
}
}
int upto = numSegments - 1;
while (upto >= start)
{
if (levels[upto] >= levelBottom)
{
break;
}
upto--;
}
if (Verbose())
{
Message(" level " + levelBottom + " to " + maxLevel + ": " + (1 + upto - start) + " segments");
}
// Finally, record all merges that are viable at this level:
int end = start + mergeFactor;
while (end <= 1 + upto)
{
bool anyTooLarge = false;
for (int i = start; i < end; i++)
{
SegmentInfo info = infos.Info(i);
anyTooLarge |= (Size(info) >= maxMergeSize || SizeDocs(info) >= maxMergeDocs);
}
if (!anyTooLarge)
{
if (spec == null)
{
spec = new MergeSpecification();
}
if (Verbose())
{
Message(" " + start + " to " + end + ": add this merge");
}
spec.Add(new OneMerge(infos.Range(start, end), useCompoundFile));
}
else if (Verbose())
{
Message(" " + start + " to " + end + ": contains segment over maxMergeSize or maxMergeDocs; skipping");
}
start = end;
end = start + mergeFactor;
}
start = 1 + upto;
}
return(spec);
}
/// <summary> Finds merges necessary to expunge all deletes from the
/// index. We simply merge adjacent segments that have
/// deletes, up to mergeFactor at a time.
/// </summary>
public override MergeSpecification FindMergesToExpungeDeletes(SegmentInfos segmentInfos)
{
int numSegments = segmentInfos.Count;
if (Verbose())
{
Message("findMergesToExpungeDeletes: " + numSegments + " segments");
}
MergeSpecification spec = new MergeSpecification();
int firstSegmentWithDeletions = -1;
for (int i = 0; i < numSegments; i++)
{
SegmentInfo info = segmentInfos.Info(i);
int delCount = writer.NumDeletedDocs(info);
if (delCount > 0)
{
if (Verbose())
{
Message(" segment " + info.name + " has deletions");
}
if (firstSegmentWithDeletions == -1)
{
firstSegmentWithDeletions = i;
}
else if (i - firstSegmentWithDeletions == mergeFactor)
{
// We've seen mergeFactor segments in a row with
// deletions, so force a merge now:
if (Verbose())
{
Message(" add merge " + firstSegmentWithDeletions + " to " + (i - 1) + " inclusive");
}
spec.Add(new OneMerge(segmentInfos.Range(firstSegmentWithDeletions, i), useCompoundFile));
firstSegmentWithDeletions = i;
}
}
else if (firstSegmentWithDeletions != -1)
{
// End of a sequence of segments with deletions, so,
// merge those past segments even if it's fewer than
// mergeFactor segments
if (Verbose())
{
Message(" add merge " + firstSegmentWithDeletions + " to " + (i - 1) + " inclusive");
}
spec.Add(new OneMerge(segmentInfos.Range(firstSegmentWithDeletions, i), useCompoundFile));
firstSegmentWithDeletions = -1;
}
}
if (firstSegmentWithDeletions != -1)
{
if (Verbose())
{
Message(" add merge " + firstSegmentWithDeletions + " to " + (numSegments - 1) + " inclusive");
}
spec.Add(new OneMerge(segmentInfos.Range(firstSegmentWithDeletions, numSegments), useCompoundFile));
}
return(spec);
}
/// <summary>Returns the merges necessary to optimize the index.
/// This merge policy defines "optimized" to mean only one
/// segment in the index, where that segment has no
/// deletions pending nor separate norms, and it is in
/// compound file format if the current useCompoundFile
/// setting is true. This method returns multiple merges
/// (mergeFactor at a time) so the {@link MergeScheduler}
/// in use may make use of concurrency.
/// </summary>
public override MergeSpecification FindMergesForOptimize(SegmentInfos infos, int maxNumSegments, System.Collections.Hashtable segmentsToOptimize)
{
MergeSpecification spec;
System.Diagnostics.Debug.Assert(maxNumSegments > 0);
if (!IsOptimized(infos, maxNumSegments, segmentsToOptimize))
{
// Find the newest (rightmost) segment that needs to
// be optimized (other segments may have been flushed
// since optimize started):
int last = infos.Count;
while (last > 0)
{
SegmentInfo info = infos.Info(--last);
if (segmentsToOptimize.Contains(info))
{
last++;
break;
}
}
if (last > 0)
{
spec = new MergeSpecification();
// First, enroll all "full" merges (size
// mergeFactor) to potentially be run concurrently:
while (last - maxNumSegments + 1 >= mergeFactor)
{
spec.Add(new OneMerge(infos.Range(last - mergeFactor, last), useCompoundFile));
last -= mergeFactor;
}
// Only if there are no full merges pending do we
// add a final partial (< mergeFactor segments) merge:
if (0 == spec.merges.Count)
{
if (maxNumSegments == 1)
{
// Since we must optimize down to 1 segment, the
// choice is simple:
if (last > 1 || !IsOptimized(infos.Info(0)))
{
spec.Add(new OneMerge(infos.Range(0, last), useCompoundFile));
}
}
else if (last > maxNumSegments)
{
// Take care to pick a partial merge that is
// least cost, but does not make the index too
// lopsided. If we always just picked the
// partial tail then we could produce a highly
// lopsided index over time:
// We must merge this many segments to leave
// maxNumSegments in the index (from when
// optimize was first kicked off):
int finalMergeSize = last - maxNumSegments + 1;
// Consider all possible starting points:
long bestSize = 0;
int bestStart = 0;
for (int i = 0; i < last - finalMergeSize + 1; i++)
{
long sumSize = 0;
for (int j = 0; j < finalMergeSize; j++)
{
sumSize += Size(infos.Info(j + i));
}
if (i == 0 || (sumSize < 2 * Size(infos.Info(i - 1)) && sumSize < bestSize))
{
bestStart = i;
bestSize = sumSize;
}
}
spec.Add(new OneMerge(infos.Range(bestStart, bestStart + finalMergeSize), useCompoundFile));
}
}
}
else
{
spec = null;
}
}
else
{
spec = null;
}
return(spec);
}
/// <summary>Checks if any merges are now necessary and returns a
/// <see cref="MergePolicy.MergeSpecification" /> if so. A merge
/// is necessary when there are more than <see cref="MergeFactor" />
/// segments at a given level. When
/// multiple levels have too many segments, this method
/// will return multiple merges, allowing the <see cref="MergeScheduler" />
/// to use concurrency.
/// </summary>
public override MergeSpecification FindMerges(SegmentInfos infos)
{
int numSegments = infos.Count;
if (Verbose())
Message("findMerges: " + numSegments + " segments");
// Compute levels, which is just log (base mergeFactor)
// of the size of each segment
float[] levels = new float[numSegments];
float norm = (float) System.Math.Log(mergeFactor);
for (int i = 0; i < numSegments; i++)
{
SegmentInfo info = infos.Info(i);
long size = Size(info);
// Floor tiny segments
if (size < 1)
size = 1;
levels[i] = (float) System.Math.Log(size) / norm;
}
float levelFloor;
if (minMergeSize <= 0)
levelFloor = (float) 0.0;
else
{
levelFloor = (float) (System.Math.Log(minMergeSize) / norm);
}
// Now, we quantize the log values into levels. The
// first level is any segment whose log size is within
// LEVEL_LOG_SPAN of the max size, or, who has such as
// segment "to the right". Then, we find the max of all
// other segments and use that to define the next level
// segment, etc.
MergeSpecification spec = null;
int start = 0;
while (start < numSegments)
{
// Find max level of all segments not already
// quantized.
float maxLevel = levels[start];
for (int i = 1 + start; i < numSegments; i++)
{
float level = levels[i];
if (level > maxLevel)
maxLevel = level;
}
// Now search backwards for the rightmost segment that
// falls into this level:
float levelBottom;
if (maxLevel < levelFloor)
// All remaining segments fall into the min level
levelBottom = - 1.0F;
else
{
levelBottom = (float) (maxLevel - LEVEL_LOG_SPAN);
// Force a boundary at the level floor
if (levelBottom < levelFloor && maxLevel >= levelFloor)
levelBottom = levelFloor;
}
int upto = numSegments - 1;
while (upto >= start)
{
if (levels[upto] >= levelBottom)
{
break;
}
upto--;
}
if (Verbose())
Message(" level " + levelBottom + " to " + maxLevel + ": " + (1 + upto - start) + " segments");
// Finally, record all merges that are viable at this level:
int end = start + mergeFactor;
while (end <= 1 + upto)
{
bool anyTooLarge = false;
for (int i = start; i < end; i++)
{
SegmentInfo info = infos.Info(i);
anyTooLarge |= (Size(info) >= maxMergeSize || SizeDocs(info) >= maxMergeDocs);
}
if (!anyTooLarge)
{
if (spec == null)
spec = new MergeSpecification();
if (Verbose())
Message(" " + start + " to " + end + ": add this merge");
spec.Add(MakeOneMerge(infos, infos.Range(start, end)));
}
else if (Verbose())
Message(" " + start + " to " + end + ": contains segment over maxMergeSize or maxMergeDocs; skipping");
start = end;
end = start + mergeFactor;
}
start = 1 + upto;
}
return spec;
}
/// <summary> Finds merges necessary to expunge all deletes from the
/// index. We simply merge adjacent segments that have
/// deletes, up to mergeFactor at a time.
/// </summary>
public override MergeSpecification FindMergesToExpungeDeletes(SegmentInfos segmentInfos)
{
int numSegments = segmentInfos.Count;
if (Verbose())
Message("findMergesToExpungeDeletes: " + numSegments + " segments");
MergeSpecification spec = new MergeSpecification();
int firstSegmentWithDeletions = - 1;
for (int i = 0; i < numSegments; i++)
{
SegmentInfo info = segmentInfos.Info(i);
int delCount = writer.NumDeletedDocs(info);
if (delCount > 0)
{
if (Verbose())
Message(" segment " + info.name + " has deletions");
if (firstSegmentWithDeletions == - 1)
firstSegmentWithDeletions = i;
else if (i - firstSegmentWithDeletions == mergeFactor)
{
// We've seen mergeFactor segments in a row with
// deletions, so force a merge now:
if (Verbose())
Message(" add merge " + firstSegmentWithDeletions + " to " + (i - 1) + " inclusive");
spec.Add(MakeOneMerge(segmentInfos, segmentInfos.Range(firstSegmentWithDeletions, i)));
firstSegmentWithDeletions = i;
}
}
else if (firstSegmentWithDeletions != - 1)
{
// End of a sequence of segments with deletions, so,
// merge those past segments even if it's fewer than
// mergeFactor segments
if (Verbose())
Message(" add merge " + firstSegmentWithDeletions + " to " + (i - 1) + " inclusive");
spec.Add(MakeOneMerge(segmentInfos, segmentInfos.Range(firstSegmentWithDeletions, i)));
firstSegmentWithDeletions = - 1;
}
}
if (firstSegmentWithDeletions != - 1)
{
if (Verbose())
Message(" add merge " + firstSegmentWithDeletions + " to " + (numSegments - 1) + " inclusive");
spec.Add(MakeOneMerge(segmentInfos, segmentInfos.Range(firstSegmentWithDeletions, numSegments)));
}
return spec;
}
/// <summary>Returns the merges necessary to optimize the index.
/// This merge policy defines "optimized" to mean only one
/// segment in the index, where that segment has no
/// deletions pending nor separate norms, and it is in
/// compound file format if the current useCompoundFile
/// setting is true. This method returns multiple merges
/// (mergeFactor at a time) so the <see cref="MergeScheduler" />
/// in use may make use of concurrency.
/// </summary>
public override MergeSpecification FindMergesForOptimize(SegmentInfos infos, int maxNumSegments, ISet<SegmentInfo> segmentsToOptimize)
{
MergeSpecification spec;
System.Diagnostics.Debug.Assert(maxNumSegments > 0);
if (!IsOptimized(infos, maxNumSegments, segmentsToOptimize))
{
// Find the newest (rightmost) segment that needs to
// be optimized (other segments may have been flushed
// since optimize started):
int last = infos.Count;
while (last > 0)
{
SegmentInfo info = infos.Info(--last);
if (segmentsToOptimize.Contains(info))
{
last++;
break;
}
}
if (last > 0)
{
spec = new MergeSpecification();
// First, enroll all "full" merges (size
// mergeFactor) to potentially be run concurrently:
while (last - maxNumSegments + 1 >= mergeFactor)
{
spec.Add(MakeOneMerge(infos, infos.Range(last - mergeFactor, last)));
last -= mergeFactor;
}
// Only if there are no full merges pending do we
// add a final partial (< mergeFactor segments) merge:
if (0 == spec.merges.Count)
{
if (maxNumSegments == 1)
{
// Since we must optimize down to 1 segment, the
// choice is simple:
if (last > 1 || !IsOptimized(infos.Info(0)))
spec.Add(MakeOneMerge(infos, infos.Range(0, last)));
}
else if (last > maxNumSegments)
{
// Take care to pick a partial merge that is
// least cost, but does not make the index too
// lopsided. If we always just picked the
// partial tail then we could produce a highly
// lopsided index over time:
// We must merge this many segments to leave
// maxNumSegments in the index (from when
// optimize was first kicked off):
int finalMergeSize = last - maxNumSegments + 1;
// Consider all possible starting points:
long bestSize = 0;
int bestStart = 0;
for (int i = 0; i < last - finalMergeSize + 1; i++)
{
long sumSize = 0;
for (int j = 0; j < finalMergeSize; j++)
sumSize += Size(infos.Info(j + i));
if (i == 0 || (sumSize < 2 * Size(infos.Info(i - 1)) && sumSize < bestSize))
{
bestStart = i;
bestSize = sumSize;
}
}
spec.Add(MakeOneMerge(infos, infos.Range(bestStart, bestStart + finalMergeSize)));
}
}
}
else
spec = null;
}
else
spec = null;
return spec;
}