[ https://issues.apache.org/jira/browse/HBASE-1177?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack updated HBASE-1177: ------------------------- Tags: noob Labels: noob (was: ) Any new dev want to take on proving this phenomeon is because of Nagles? The 40ms does seem to correlate strongly. > Delay when client is located on the same node as the regionserver > ----------------------------------------------------------------- > > Key: HBASE-1177 > URL: https://issues.apache.org/jira/browse/HBASE-1177 > Project: HBase > Issue Type: Bug > Components: performance > Affects Versions: 0.19.0 > Environment: Linux 2.6.25 x86_64 > Reporter: Jonathan Gray > Labels: noob > Attachments: Contribution of getClosest to getRow time.jpg, > Contribution of next to getRow time.jpg, Contribution of seekTo to getClosest > time.jpg, Elapsed time of RowResults.readFields.jpg, ReadDelayTest.java, > RowResults.readFields zoomed.jpg, getRow + round-trip vs # columns.jpg, > getRow times.jpg, screenshot-1.jpg, screenshot-2.jpg, screenshot-3.jpg, > screenshot-4.jpg, zoom of columns vs round-trip blowup.jpg > > > During testing of HBASE-80, we uncovered a strange 40ms delay for random > reads. We ran a series of tests and found that it only happens when the > client is on the same node as the RS and for a certain range of payloads (not > specifically related to number of columns or size of them, only total > payload). It appears to be precisely 40ms every time. > Unsure if this is particular to our architecture, but it does happen on all > nodes we've tried. Issue completely goes away with very large payloads or > moving the client. > Will post a test program tomorrow if anyone can test on a different > architecture. > Making a blocker for 0.20. Since this happens when you have an MR task > running local to the RS, and this is what we try to do, might also consider > making this a blocker for 0.19.1. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira