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Hudson commented on HDFS-9412: ------------------------------ FAILURE: Integrated in Hadoop-trunk-Commit #9625 (See [https://builds.apache.org/job/Hadoop-trunk-Commit/9625/]) HDFS-9412. getBlocks occupies FSLock and takes too long to complete. (waltersu4549: rev 67523ffcf491f4f2db5335899c00a174d0caaa9b) * hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java * hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestGetBlocks.java > getBlocks occupies FSLock and takes too long to complete > -------------------------------------------------------- > > Key: HDFS-9412 > URL: https://issues.apache.org/jira/browse/HDFS-9412 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: He Tianyi > Assignee: He Tianyi > Fix For: 2.8.0 > > Attachments: HDFS-9412.0000.patch, HDFS-9412.0001.patch, > HDFS-9412.0002.patch > > > {{getBlocks}} in {{NameNodeRpcServer}} acquires a read lock then may take a > long time to complete (probably several seconds, if number of blocks are too > much). > During this period, other threads attempting to acquire write lock will wait. > In an extreme case, RPC handlers are occupied by one reader thread calling > {{getBlocks}} and all other threads waiting for write lock, rpc server acts > like hung. Unfortunately, this tends to happen in heavy loaded cluster, since > read operations come and go fast (they do not need to wait), leaving write > operations waiting. > Looks like we can optimize this thing like DN block report did in past, by > splitting the operation into smaller sub operations, and let other threads do > their work between each sub operation. The whole result is returned at once, > though (one thing different from DN block report). > I am not sure whether this will work. Any better idea? -- This message was sent by Atlassian JIRA (v6.3.4#6332)