Todd Lipcon has posted comments on this change. ( http://gerrit.cloudera.org:8080/7221 )
Change subject: Simplify OpId/Timestamp assignment and make it atomic ...................................................................... Patch Set 21: (2 comments) Just looked at TransactionDriver first since David asked for a quick review of that part http://gerrit.cloudera.org:8080/#/c/7221/21/src/kudu/tablet/transactions/transaction_driver.cc File src/kudu/tablet/transactions/transaction_driver.cc: http://gerrit.cloudera.org:8080/#/c/7221/21/src/kudu/tablet/transactions/transaction_driver.cc@324 PS21, Line 324: std::lock_guard<simple_spinlock> lock(lock_); would it be correct here to add a DCHECK_EQ(transaction_->type(), consensus::LEADER)? I think so. Maybe would be good doc value. http://gerrit.cloudera.org:8080/#/c/7221/21/src/kudu/tablet/transactions/transaction_driver.cc@341 PS21, Line 341: MvccManager::ScopedCleanTimeAdvancePin pin(replica->tablet()->mvcc_manager(), : replica->clock()->Now()) I'm surprised that the clock()->Now() call doesn't need to be made inside of the MVCC lock. Otherwise isn't it racey? T1: call clock->Now() T2: advance clean time to a higher value T1: call Pin(older timestamp than current clean time) .. or are we relying on the fact that there can be no T2 starting a transaction at a higher 'Now' because the only thread that starts transactions is the prepare thread? Maybe needs some comment on that if it's the case. -- To view, visit http://gerrit.cloudera.org:8080/7221 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I2bedcc5c3708d06f48131f34ea14c835867b4800 Gerrit-Change-Number: 7221 Gerrit-PatchSet: 21 Gerrit-Owner: David Ribeiro Alves <davidral...@gmail.com> Gerrit-Reviewer: Alexey Serbin <aser...@cloudera.com> Gerrit-Reviewer: David Ribeiro Alves <davidral...@gmail.com> Gerrit-Reviewer: Kudu Jenkins Gerrit-Reviewer: Mike Percy <mpe...@apache.org> Gerrit-Reviewer: Tidy Bot Gerrit-Reviewer: Todd Lipcon <t...@apache.org> Gerrit-Comment-Date: Wed, 21 Mar 2018 19:53:16 +0000 Gerrit-HasComments: Yes
