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stack commented on HBASE-7336: ------------------------------ +1 on committing this for now. On Reader per long-running scanner, it will complicate the swapping in of new files on compaction but probably worth figuring out. Lets file issues for further improvement. Good stuff Lars. > HFileBlock.readAtOffset does not work well with multiple threads > ---------------------------------------------------------------- > > Key: HBASE-7336 > URL: https://issues.apache.org/jira/browse/HBASE-7336 > Project: HBase > Issue Type: Sub-task > Reporter: Lars Hofhansl > Assignee: Lars Hofhansl > Priority: Critical > Fix For: 0.96.0, 0.94.4 > > Attachments: 7336-0.94.txt, 7336-0.96.txt > > > HBase grinds to a halt when many threads scan along the same set of blocks > and neither read short circuit is nor block caching is enabled for the dfs > client ... disabling the block cache makes sense on very large scans. > It turns out that synchronizing in istream in HFileBlock.readAtOffset is the > culprit. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira