Updated Branches: refs/heads/trunk 4c28cfb57 -> e9c3ee979
comments and simplify comparator Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/e9c3ee97 Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/e9c3ee97 Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/e9c3ee97 Branch: refs/heads/trunk Commit: e9c3ee979f1f0dca49b002a2892bd23c6f69235c Parents: 4c28cfb Author: Jonathan Ellis <jbel...@apache.org> Authored: Wed Apr 3 11:39:13 2013 -0500 Committer: Jonathan Ellis <jbel...@apache.org> Committed: Wed Apr 3 11:39:21 2013 -0500 ---------------------------------------------------------------------- .../compaction/SizeTieredCompactionStrategy.java | 16 +++++--------- 1 files changed, 6 insertions(+), 10 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/cassandra/blob/e9c3ee97/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java ---------------------------------------------------------------------- diff --git a/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java b/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java index 8d990e5..6febc07 100644 --- a/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java +++ b/src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java @@ -19,8 +19,8 @@ package org.apache.cassandra.db.compaction; import java.util.*; import java.util.Map.Entry; -import java.util.concurrent.Callable; +import com.google.common.primitives.Longs; import org.slf4j.Logger; import org.slf4j.LoggerFactory; @@ -28,7 +28,6 @@ import org.apache.cassandra.cql3.CFPropDefs; import org.apache.cassandra.db.ColumnFamilyStore; import org.apache.cassandra.exceptions.ConfigurationException; import org.apache.cassandra.io.sstable.SSTableReader; -import org.apache.cassandra.utils.FBUtilities; import org.apache.cassandra.utils.Pair; public class SizeTieredCompactionStrategy extends AbstractCompactionStrategy @@ -75,6 +74,7 @@ public class SizeTieredCompactionStrategy extends AbstractCompactionStrategy logger.debug("Compaction buckets are {}", buckets); updateEstimatedCompactionsByTasks(buckets); + // skip buckets containing less than minThreshold sstables, and limit other buckets to maxThreshold entries List<List<SSTableReader>> prunedBuckets = new ArrayList<List<SSTableReader>>(); for (List<SSTableReader> bucket : buckets) { @@ -92,10 +92,10 @@ public class SizeTieredCompactionStrategy extends AbstractCompactionStrategy prunedBuckets.add(prunedBucket); } + // if there is no sstable to compact in standard way, try compacting single sstable whose droppable tombstone + // ratio is greater than threshold. if (prunedBuckets.isEmpty()) { - // if there is no sstable to compact in standard way, try compacting single sstable whose droppable tombstone - // ratio is greater than threshold. for (List<SSTableReader> bucket : buckets) { for (SSTableReader table : bucket) @@ -109,16 +109,12 @@ public class SizeTieredCompactionStrategy extends AbstractCompactionStrategy return Collections.emptyList(); } + // prefer compacting buckets with smallest average size; that will yield the fastest improvement for read performance return Collections.min(prunedBuckets, new Comparator<List<SSTableReader>>() { public int compare(List<SSTableReader> o1, List<SSTableReader> o2) { - long n = avgSize(o1) - avgSize(o2); - if (n < 0) - return -1; - if (n > 0) - return 1; - return 0; + return Longs.compare(avgSize(o1), avgSize(o2)); } private long avgSize(List<SSTableReader> sstables)
