Andrew Wong has posted comments on this change. ( http://gerrit.cloudera.org:8080/16569 )
Change subject: KUDU-2612: persist commit MVCC op timestamp in txn metadata ...................................................................... Patch Set 1: (1 comment) http://gerrit.cloudera.org:8080/#/c/16569/1/src/kudu/tablet/tablet_metadata.cc File src/kudu/tablet/tablet_metadata.cc: http://gerrit.cloudera.org:8080/#/c/16569/1/src/kudu/tablet/tablet_metadata.cc@817 PS1, Line 817: if we are bootstrapping > Wondering In which cases the mvcc op for a txn can be already persisted but This happens when we are bootstrapping and replay a BEGIN_COMMIT op, since we have to replay WAL ops to rebuild in-memory state. Take this example: BEGIN_TXN 1 (txn metadata is added in tablet metadata) BEGIN_COMMIT 1 (op timestamp is updated in txn metadata) FLUSH (txn metadata is persisted) RESTART In this scenario, after restarting, we see that we have an in-flight (not finalized or aborted) txn 1 persisted in metadata, so we create a new Txn object to indicate that there is an on-going Txn. Then we replay all ops for it, including the BEGIN_COMMIT op to get the participant's state to kCommitInProgress. But we don't need to anchor the WAL for this metadata flush because the metadata has already been persisted. -- To view, visit http://gerrit.cloudera.org:8080/16569 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ib2400fbb7e96ddba78544a9549965fc095e32ca3 Gerrit-Change-Number: 16569 Gerrit-PatchSet: 1 Gerrit-Owner: Andrew Wong <aw...@cloudera.com> Gerrit-Reviewer: Andrew Wong <aw...@cloudera.com> Gerrit-Reviewer: Hao Hao <hao....@cloudera.com> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Comment-Date: Mon, 19 Oct 2020 20:41:30 +0000 Gerrit-HasComments: Yes
