Thanks Jingcheng Yes, it just references the source MOB data until MOB compaction.
Based on that, I think this really is a critical bug. It allowed the MOBs to be deleted before that happened, and thus broken references and data loss. Or am I misunderstanding you please? On Thu, Oct 13, 2016 at 9:45 AM, Du, Jingcheng <[email protected]> wrote: > Hi Tim, > > > was this running a background task to copy the MOB data when the > snapshot was cloned and I just deleted the source before the copy was > complete? > The MOB data can be copied when mob compaction happens. But the MOB files > should not be deleted even if they are not copied and after the source > table is deleted. The archive cleaner should keep them until all the > references are gone. Let me check the code again. > > > when running "snapshot and clone" it just references the source MOB data > until a (?) change? > Yes, it just references the source MOB data until MOB compaction. > > > snapshot and clone just doesn't support MOB? > It supports. > > Regards, > Jingcheng > > -----Original Message----- > From: Tim Robertson [mailto:[email protected]] > Sent: Thursday, October 13, 2016 1:56 AM > To: [email protected] > Subject: Re: Data loss in MOB snapshot and clone? > > Thanks - well it is now on the CDH community forum too. > > Jonathan Hsieh pretty much described what I see in his comment on > HBASE-12332 > https://issues.apache.org/jira/browse/HBASE-12332? > focusedCommentId=14241478&page=com.atlassian.jira. > plugin.system.issuetabpanels:comment-tabpanel#comment-14241478 > > > > On Wed, Oct 12, 2016 at 7:51 PM, Huaxiang Sun <[email protected]> wrote: > > > Hi Tim,, > > > > Just read more details, it may not be related with the issue we fixed > > (mob compaction related). > > I am doing a similar test to see if I can reproduce it. > > > > Thanks, > > Huaxiang > > > On Oct 12, 2016, at 10:29 AM, Tim Robertson > > > <[email protected]> > > wrote: > > > > > > Thanks Ted, Huaxiang > > > > > > I'll move this to a Cloudera forum and comment back here if it > > > appears unrelated. > > > > > > On Wed, Oct 12, 2016 at 7:24 PM, Huaxiang Sun <[email protected] > > <mailto:[email protected]>> wrote: > > > > > >> By the way, I forgot the forum link: http://community.cloudera.com > > >> < > > http://community.cloudera.com/> < > > >> http://community.cloudera.com/ <http://community.cloudera.com/>> > > >> > > >> Thanks, > > >> Huaxiang > > >> > > >>> On Oct 12, 2016, at 10:10 AM, Huaxiang Sun <[email protected] > <mailto: > > [email protected]>> wrote: > > >>> > > >>> Hi Tim, > > >>> > > >>> I believe that it runs into an issue which is specific to > > >>> cloudera > > >> release we fixed recently. For details, could you discuss it in cdh > > forum? > > >>> Copy me([email protected] <mailto:[email protected]> <mailto: > > [email protected] <mailto:[email protected]>>) in the forum so I > > >> can explain more there. > > >>> > > >>> Thanks, > > >>> Huaxiang > > >>> > > >>>> On Oct 12, 2016, at 8:13 AM, Ted Yu <[email protected] <mailto: > > [email protected]> <mailto: > > >> [email protected] <mailto:[email protected]>>> wrote: > > >>>> > > >>>> Have you looked at HBASE-16578 ? > > >>>> > > >>>> Cheers > > >>>> > > >>>>> On Oct 12, 2016, at 8:02 AM, Tim Robertson < > > [email protected] <mailto:[email protected]> > > >> <mailto:[email protected] > > >> <mailto:[email protected]>>> > > wrote: > > >>>>> > > >>>>> Hi devs, > > >>>>> [Had a quick chat with Lars G. about this and before opening a > > >>>>> Jira I thought I'd raise it here first] > > >>>>> > > >>>>> We have just experienced data loss in HBase 1.0.0-cdh5.4.10. > > >>>>> > > >>>>> Before I dig into this further, I'd like to just ask if anyone > > >>>>> has > > seen > > >>>>> this before? > > >>>>> > > >>>>> The initial state was a table (tim_test) built with MOB support > > >>>>> and a > > >> few > > >>>>> 10's million rows and 10's billions of cells. > > >>>>> > > >>>>> I wanted to rename the table to get this into production and did > > >>>>> so > > as > > >>>>> follows: > > >>>>> > > >>>>> snapshot 'tim_test', 'tim_test-snapshot' > > >>>>> clone_snapshot 'tim_test-snapshot', 'prod_b_map' > > >>>>> > > >>>>> At this stage the application all looked good, and so I > > >>>>> continued > > with: > > >>>>> > > >>>>> delete_snapshot 'tim_test-snapshot' > > >>>>> disable 'tim_test' > > >>>>> drop ‘tim_test’ > > >>>>> > > >>>>> Then things went... awry and data just started dropping out in > > >>>>> the > > app. > > >>>>> Before long, all MOB data seemingly is gone. > > >>>>> > > >>>>> The references in the new table MOB folder appear to point to > > >>>>> the > > >> source > > >>>>> table (e.g. > > >>>>> /hbase/mobdir/data/default/prod_b_map/ba42a2e8e9b669d9fc85bdfeed > > >>>>> 2f5f > > >> 2a/EPSG_4326/tim_test=14bf5f1737ac65c34615ed97c0b7de06- > > >> d41d8cd98f00b204e9800998ecf8427e20161006ff8baa70d21f408caefe > > 8ae6318dfba2). > > >>>>> > > >>>>> The RS logs full of ERROR like: > > >>>>> > > >>>>> 2016-10-12 15:19:14,640 ERROR org.apache.hadoop.hbase. > > >> regionserver.HStore: > > >>>>> The mob file > > >>>>> d41d8cd98f00b204e9800998ecf8427e20161006b59865f80e604781a79e > > >> bfa2ddd66b48 > > >>>>> could not be found in the locations > > >>>>> [hdfs://ha-nn/hbase/mobdir/data/default/tim_test/ > > >> 14bf5f1737ac65c34615ed97c0b7de06/EPSG_4326 > > >> <hdfs://ha-nn/hbase/mobdir/ > > <hdfs://ha-nn/hbase/mobdir/> > > >> data/default/tim_test/14bf5f1737ac65c34615ed97c0b7de06/EPSG_4326>, > > >>>>> hdfs://ha-nn/hbase/archive/data/default/tim_test/ > > <hdfs://ha-nn/hbase/archive/data/default/tim_test/> > > >> 14bf5f1737ac65c34615ed97c0b7de06/EPSG_4326] > > <hdfs://ha-nn/hbase/archive/ > > >> data/default/tim_test/14bf5f1737ac65c34615ed97c0b7de06/EPSG_4326]> > > >>>>> > > >>>>> What I don't know is: > > >>>>> 1) was this running a background task to copy the MOB data when > > >>>>> the snapshot was cloned and I just deleted the source before the > > >>>>> copy was complete? > > >>>>> - or > > >>>>> 2) when running "snapshot and clone" it just references the > > >>>>> source > > MOB > > >>>>> data until a (?) change? > > >>>>> 3) snapshot and clone just doesn't support MOB? > > >>>>> > > >>>>> Can anyone shed some light on this easily before I dig into it > > please? > > >>>>> > > >>>>> While this situation exists (at least in 1.0.0) might it be good > > >>>>> to > > get > > >>>>> info about data loss for MOB tables into the snapshot clone docs? > > >>>>> > > >>>>> Thanks, > > >>>>> Tim > > > > >
