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Posted to commits@cassandra.apache.org by jb...@apache.org on 2012/12/27 16:11:15 UTC
[6/13] git commit: Improve handling a changing target throttle rate
mid-compaction patch by J.B. Langston; reviewed by jbellis for CASSANDRA-5087
Improve handling a changing target throttle rate mid-compaction
patch by J.B. Langston; reviewed by jbellis for CASSANDRA-5087
Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/3d01ec7e
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/3d01ec7e
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/3d01ec7e
Branch: refs/heads/cassandra-1.2
Commit: 3d01ec7e752ec31761ec45637258bc57c6d0f4cc
Parents: 6018709
Author: Jonathan Ellis <jb...@apache.org>
Authored: Thu Dec 27 09:32:38 2012 -0500
Committer: Jonathan Ellis <jb...@apache.org>
Committed: Thu Dec 27 10:09:45 2012 -0500
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CHANGES.txt | 1 +
src/java/org/apache/cassandra/utils/Throttle.java | 14 +++++++++++---
2 files changed, 12 insertions(+), 3 deletions(-)
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http://git-wip-us.apache.org/repos/asf/cassandra/blob/3d01ec7e/CHANGES.txt
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diff --git a/CHANGES.txt b/CHANGES.txt
index a36ccd2..55a6bb5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
1.1.9
+ * Improve handling a changing target throttle rate mid-compaction (CASSANDRA-5087)
* fix multithreaded compaction deadlock (CASSANDRA-4492)
* fix specifying and altering crc_check_chance (CASSANDRA-5053)
* Don't expire columns sooner than they should in 2ndary indexes (CASSANDRA-5079)
http://git-wip-us.apache.org/repos/asf/cassandra/blob/3d01ec7e/src/java/org/apache/cassandra/utils/Throttle.java
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diff --git a/src/java/org/apache/cassandra/utils/Throttle.java b/src/java/org/apache/cassandra/utils/Throttle.java
index c5f7632..83cd007 100644
--- a/src/java/org/apache/cassandra/utils/Throttle.java
+++ b/src/java/org/apache/cassandra/utils/Throttle.java
@@ -52,7 +52,7 @@ public class Throttle
throttleDelta(currentBytes - bytesAtLastDelay);
}
- /** @param bytesDelta Bytes of throughput since the last call to throttle*(). */
+ /** @param bytesDelta Bytes of throughput since the last call to throttle*() */
public void throttleDelta(long bytesDelta)
{
int newTargetBytesPerMS = fun.targetThroughput();
@@ -60,10 +60,18 @@ public class Throttle
// throttling disabled
return;
- // if the target changed, log
if (newTargetBytesPerMS != targetBytesPerMS)
+ {
+ // restart throttling based on the new target to avoid getting bogus answers based on comparing
+ // the rate under the old throttle, with the desired rate under the new. (If the new rate is higher
+ // than the old, it doesn't much matter, but if the new rate is lower, it would result in a long
+ // sleep to bring the average down. See CASSANDRA-5087.)
logger.debug("{} target throughput now {} bytes/ms.", this, newTargetBytesPerMS);
- targetBytesPerMS = newTargetBytesPerMS;
+ targetBytesPerMS = newTargetBytesPerMS;
+ bytesAtLastDelay += bytesDelta;
+ timeAtLastDelay = System.currentTimeMillis();
+ return;
+ }
// time passed since last delay
long msSinceLast = System.currentTimeMillis() - timeAtLastDelay;