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Posted to commits@cassandra.apache.org by jb...@apache.org on 2012/04/19 01:14:20 UTC
[5/6] git commit: average a reduced liveRatio estimate with the
previous one patch by Daniel Doubleday; reviewed by jbellis for CASSANDRA-4065
average a reduced liveRatio estimate with the previous one
patch by Daniel Doubleday; reviewed by jbellis for CASSANDRA-4065
Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/43a472e1
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/43a472e1
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/43a472e1
Branch: refs/heads/cassandra-1.1.0
Commit: 43a472e13a38e4cd0420d7fb668a70464fa31ada
Parents: df7776b
Author: Jonathan Ellis <jb...@apache.org>
Authored: Wed Apr 18 18:13:48 2012 -0500
Committer: Jonathan Ellis <jb...@apache.org>
Committed: Wed Apr 18 18:13:48 2012 -0500
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CHANGES.txt | 1 +
src/java/org/apache/cassandra/db/Memtable.java | 12 +++++++++---
2 files changed, 10 insertions(+), 3 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/cassandra/blob/43a472e1/CHANGES.txt
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diff --git a/CHANGES.txt b/CHANGES.txt
index b8de41f..c6fa3d3 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
1.1-dev
+ * average a reduced liveRatio estimate with the previous one (CASSANDRA-4065)
* Allow KS and CF names up to 48 characters (CASSANDRA-4157)
* Add support for CL.TWO and CL.THREE in CQL (CASSANDRA-4156)
Merged from 1.0:
http://git-wip-us.apache.org/repos/asf/cassandra/blob/43a472e1/src/java/org/apache/cassandra/db/Memtable.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/db/Memtable.java b/src/java/org/apache/cassandra/db/Memtable.java
index d9e9570..1eddf15 100644
--- a/src/java/org/apache/cassandra/db/Memtable.java
+++ b/src/java/org/apache/cassandra/db/Memtable.java
@@ -194,15 +194,21 @@ public class Memtable
if (newRatio < MIN_SANE_LIVE_RATIO)
{
- logger.warn("setting live ratio to minimum of 1.0 instead of {}", newRatio);
+ logger.warn("setting live ratio to minimum of {} instead of {}", MIN_SANE_LIVE_RATIO, newRatio);
newRatio = MIN_SANE_LIVE_RATIO;
}
if (newRatio > MAX_SANE_LIVE_RATIO)
{
- logger.warn("setting live ratio to maximum of 64 instead of {}", newRatio);
+ logger.warn("setting live ratio to maximum of {} instead of {}", MAX_SANE_LIVE_RATIO, newRatio);
newRatio = MAX_SANE_LIVE_RATIO;
}
- cfs.liveRatio = Math.max(cfs.liveRatio, newRatio);
+
+ // we want to be very conservative about our estimate, since the penalty for guessing low is OOM
+ // death. thus, higher estimates are believed immediately; lower ones are averaged w/ the old
+ if (newRatio > cfs.liveRatio)
+ cfs.liveRatio = newRatio;
+ else
+ cfs.liveRatio = (cfs.liveRatio + newRatio) / 2.0;
logger.info("{} liveRatio is {} (just-counted was {}). calculation took {}ms for {} columns",
new Object[]{ cfs, cfs.liveRatio, newRatio, System.currentTimeMillis() - start, objects });