[ https://issues.apache.org/jira/browse/HBASE-15158?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack updated HBASE-15158: -------------------------- Attachment: 15158.patch This patch is a carry-over from HBASE-15082 with some small changes to address test failures reported by hadoopqa. I don't have all issues squashed and I think I can break this patch up into smaller pieces still, but I want to get an overnight hadoopqa run in... so posting what I have. > Change order in which we do write pipeline operations; do all under row locks! > ------------------------------------------------------------------------------ > > Key: HBASE-15158 > URL: https://issues.apache.org/jira/browse/HBASE-15158 > Project: HBase > Issue Type: Sub-task > Components: Performance > Reporter: stack > Assignee: stack > Fix For: 2.0.0 > > Attachments: 15158.patch > > > Change how we do our write pipeline. I want to do all write pipeline ops > under row lock so I lean on this fact fixing performance regression in > check-and-set type operations like increment, append, and checkAnd* (see > sibling issue HBASE-15082). > To be specific, we write like this now: > {code} > # take rowlock > # start mvcc > # append to WAL > # add to memstore > # let go of rowlock > # sync WAL > # in case of error: rollback memstore > {code} > Instead, write like this: > {code} > # take rowlock > # start mvcc > # append to WAL > # sync WAL > # add to memstore > # let go of rowlock > ... no need to do rollback. > {code} > The old ordering was put in place because it got better performance in a time > when WAL was different and before row locks were read/write (HBASE-12751). > Testing in branch-1 shows that a reordering and skipping mvcc waits gets us > back to the performance we had before we unified mvcc and sequenceid > (HBASE-8763). Tests in HBASE-15046 show that at the macro level using our > usual perf tools, reordering pipeline seems to cause no slowdown (see > HBASE-15046). A rough compare of increments with reordered write pipeline > seems to have us getting back a bunch of our performance (see tail of > https://issues.apache.org/jira/browse/HBASE-15082?focusedCommentId=15111703&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15111703 > and subsequent comment). -- This message was sent by Atlassian JIRA (v6.3.4#6332)