Replied on jira, I think we missed an important scenario when testing. Thanks.
Stack <[email protected]> 于2020年11月15日周日 上午2:30写道： > HBASE-18070 makes it so hbase:meta read replicas can run closer to the > primary, (< second lags rather than minutes). It adds Async WAL > Replication[1] on the hbase:meta table; i.e. edits are sprayed across > replicas as they arrive at the primary's WAL. Before this work, Async WAL > Replication was only available on user-space tables and the only option for > hbase:meta read replicas was reloading the primaries hfiles on a period > (minutes). HBASE-18070 also adds an optional client-side 'LoadBalance' > policy that favors read replicas ahead of primary reads falling back to the > primary on fault. Together, these additions allow distributing hbase:meta > read load across primary and replicas alleviating 'hotspotting'. > > I would like to merge the feature to master branch Monday evening if there > is no objection (Soon after I'll merge to branch-2 so this feature can > hopefully be included in the upcoming 2.4.0RC). > > * For the design, see [2]. > * For an amalgamated PR of the 5 or 6 reviewed PRs that comprise this > feature, see [3]. > * For a PE report that compared performance before and after, see > HBASE-25127 (no regression). > * A report on ITBLL runs is pending to be attached to HBASE-18070 but runs > so far show no regression with the feature enabled (ITBLL runs were done > against a backport of this feature to branch-2 as the ITBLL state of master > is currently an unknown). > > Testing continues mainly looking for further improvement and to better > understand this feature in operation. Documentation is included but in need > of polish (working on it). > > Dump any questions here and I'll be happy to respond. If you need more time > to review, just shout. > > Thanks and thanks to all who contributed to this feature; the reviewers and > the testers in particular. > > S > > 1. http://hbase.apache.org/book.html#_asnyc_wal_replication > 2. > > https://docs.google.com/document/d/1jJWVc-idHhhgL4KDRpjMsQJKCl_NRaCLGiH3Wqwd3O8/edit# > This patch is currently missing HBASE-25280, a bug found in testing. > 3. https://github.com/apache/hbase/pull/2643 >
