[ https://issues.apache.org/jira/browse/HIVE-10128?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Sergey Shelukhin resolved HIVE-10128. ------------------------------------- Resolution: Duplicate > LLAP: BytesBytesMultiHashMap does not allow concurrent read-only access > ----------------------------------------------------------------------- > > Key: HIVE-10128 > URL: https://issues.apache.org/jira/browse/HIVE-10128 > Project: Hive > Issue Type: Sub-task > Reporter: Gopal V > Assignee: Sergey Shelukhin > Attachments: hashmap-sync-source.png, hashmap-sync.png > > > The multi-threaded performance takes a serious hit when LLAP shares > hashtables between the probe threads running in parallel. > !hashmap-sync.png! > This is an explicit synchronized block inside ReusableRowContainer which > triggers this particular pattern. > !hashmap-sync-source.png! > Looking deeper into the code, the synchronization seems to be caused due to > the fact that WriteBuffers.setReadPoint modifies the otherwise read-only > hashtable. > To generate this sort of result, run LLAP at a WARN log-level, to avoid all > the log synchronization that otherwise affects the thread sync. -- This message was sent by Atlassian JIRA (v6.3.4#6332)