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Posted to mapreduce-issues@hadoop.apache.org by "zhaoyunjiong (JIRA)" <ji...@apache.org> on 2013/07/02 09:09:23 UTC
[jira] [Created] (MAPREDUCE-5368) Save memory by set capacity,
load factor and concurrency level for ConcurrentHashMap in TaskInProgress
zhaoyunjiong created MAPREDUCE-5368:
---------------------------------------
Summary: Save memory by set capacity, load factor and concurrency level for ConcurrentHashMap in TaskInProgress
Key: MAPREDUCE-5368
URL: https://issues.apache.org/jira/browse/MAPREDUCE-5368
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: mrv1
Affects Versions: 1.2.0
Reporter: zhaoyunjiong
Fix For: 1.2.1
Below is histo from our JobTracker:
num #instances #bytes class name
----------------------------------------------
1: 136048824 11347237456 [C
2: 124156992 5959535616 java.util.concurrent.locks.ReentrantLock$NonfairSync
3: 124156973 5959534704 java.util.concurrent.ConcurrentHashMap$Segment
4: 135887753 5435510120 java.lang.String
5: 124213692 3975044400 [Ljava.util.concurrent.ConcurrentHashMap$HashEntry;
6: 63777311 3061310928 java.util.HashMap$Entry
7: 35038252 2803060160 java.util.TreeMap
8: 16921110 2712480072 [Ljava.util.HashMap$Entry;
9: 4803617 2420449192 [Ljava.lang.Object;
10: 50392816 2015712640 org.apache.hadoop.mapred.Counters$Counter
11: 7775438 1181866576 [Ljava.util.concurrent.ConcurrentHashMap$Segment;
12: 3882847 1118259936 org.apache.hadoop.mapred.TaskInProgress
ConcurrentHashMap takes more than 14G(5959535616 + 5959534704 + 3975044400).
The trouble maker are below codes in TaskInProgress.java:
Map<TaskAttemptID, Locality> taskLocality =
new ConcurrentHashMap<TaskAttemptID, Locality>();
Map<TaskAttemptID, Avataar> taskAvataar =
new ConcurrentHashMap<TaskAttemptID, Avataar>();
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