[
https://issues.apache.org/jira/browse/HBASE-13853?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14576598#comment-14576598
]
Duo Zhang commented on HBASE-13853:
-----------------------------------
I think we could back port the patch on HBASE-13811 to branch-1.1 without the
clean up and abstraction of SequenceIdAccounting? We'd better keep the WAL
interface same if possible?
> ITBLL data loss in HBase-1.1
> ----------------------------
>
> Key: HBASE-13853
> URL: https://issues.apache.org/jira/browse/HBASE-13853
> Project: HBase
> Issue Type: Bug
> Reporter: Enis Soztutar
> Assignee: Enis Soztutar
> Priority: Blocker
> Fix For: 2.0.0, 1.1.1
>
> Attachments: hbase-13853_v1-branch-1.1.patch
>
>
> After 2 days of log mining with ITBLL Search tool (thanks Stack, BTW for the
> tool), the sequence of events are like this:
> One of mappers from Search reportedly finds missing keys in some WAL file:
> {code}
> 2015-06-07 06:49:24,573 INFO [main] org.apache.hadoop.mapred.MapTask:
> Processing split:
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/oldWALs/os-enis-dal-test-jun-4-4.openstacklocal%2C16020%2C1433636320201.default.1433637872643
> (-9223372036854775808:9223372036854775807) length:132679657 2015-06-07
> 06:49:24,639 INFO [main] org.apache.hadoop.hbase.mapreduce.WALInputFormat:
> Opening reader for
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/oldWALs/os-enis-dal-test-jun-4-4.openstacklocal%2C16020%2C1433636320201.default.1433637872643
> (-9223372036854775808:9223372036854775807) length:132679657
> 2015-06-07 06:50:16,383 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Loaded keys
> to find: count=2384870 2015-06-07 06:50:16,607 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC/meta:prev/1433637873293/Put/vlen=16/seqid=0
> 2015-06-07 06:50:16,663 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC/meta:count/1433637873293/Put/vlen=8/seqid=0
> 2015-06-07 06:50:16,664 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC/meta:client/1433637873293/Put/vlen=71/seqid=0
> 2015-06-07 06:50:16,671 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=$\x1A\x99\x06\x86\xE7\x07\xA2\xA7\xB2\xFB\xCEP\x12"\x04/meta:prev/1433637873293/Put/vlen=16/seqid=0
> 2015-06-07 06:50:16,672 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=$\x1A\x99\x06\x86\xE7\x07\xA2\xA7\xB2\xFB\xCEP\x12"\x04/meta:count/1433637873293/Put/vlen=8/seqid=0
> 2015-06-07 06:50:16,678 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=$\x1A\x99\x06\x86\xE7\x07\xA2\xA7\xB2\xFB\xCEP\x12"\x04/meta:client/1433637873293/Put/vlen=71/seqid=0
> 2015-06-07 06:50:16,679 INFO [main]
> org.apache.hadoop.hbase.test.IntegrationTestBigLinkedList$Search: Found
> cell=\x1F\x80#\x95\xAE:i=)S\x01\x08
> \xD6\xFF\xD5/meta:prev/1433637873293/Put/vlen=16/seqid=0
> {code}
> {{hlog -p}} confirms the missing keys are there in the file:
> {code}
> Sequence=7276 , region=b086e29f909c9790446cd457c1ea7674 at write
> timestamp=Sun Jun 07 00:44:33 UTC 2015
> row=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC, column=meta:prev
> value: \x1B\xF5\xF3^\x8D\xB4\x85\xE3\xF4wS\x9A]\x0D\xABe
> row=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC, column=meta:count
> value: \x00\x00\x00\x00\x002\x87l
> row=!+\xF1CB\x08\x13\xA0W\x94\xC4\x1C\xDA\x1D\x0D\xBC, column=meta:client
> value: Job: job_1433466891829_0002 Task:
> attempt_1433466891829_0002_m_000003_0
> {code}
> When the RS gets killing from CM, master does WAL splitting:
> {code}
> ./hbase-hbase-regionserver-os-enis-dal-test-jun-4-2.log:2015-06-07
> 00:46:12,581 INFO [RS_LOG_REPLAY_OPS-os-enis-dal-test-jun-4-2:16020-0]
> wal.WALSplitter: Processed 2971 edits across 4 regions; edits skipped=740;
> log
> file=hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/WALs/os-enis-dal-test-jun-4-4.openstacklocal,16020,1433636320201-splitting/os-enis-dal-test-jun-4-4.openstacklocal%2C16020%2C1433636320201.default.1433637872643,
> length=132679657, corrupted=false, progress failed=false
> {code}
> The edits with Sequence=7276 should be in this recovered.edits file:
> {code}
> 2015-06-07 00:46:12,574 INFO [split-log-closeStream-2] wal.WALSplitter:
> Closed wap
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/data/default/IntegrationTestBigLinkedList/b086e29f909c9790446cd457c1ea7674/recovered.edits/0000000000000007276.temp
> (wrote 739 edits in 3950ms)
> 2015-06-07 00:46:12,580 INFO [split-log-closeStream-2] wal.WALSplitter:
> Rename
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/data/default/IntegrationTestBigLinkedList/b086e29f909c9790446cd457c1ea7674/recovered.edits/0000000000000007276.temp
> to
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/data/default/IntegrationTestBigLinkedList/b086e29f909c9790446cd457c1ea7674/recovered.edits/0000000000000008752
> {code}
> Notice that the file {{0000000000000008752}} should contain {{(wrote 739
> edits in 3950ms)}}.
> When the region gets opened again, it replays the recovered.edits files:
> {code}
> 2015-06-07 00:46:17,764 DEBUG
> [RS_OPEN_REGION-os-enis-dal-test-jun-4-5:16020-0] regionserver.HRegion: Found
> 4 recovered edits file(s) under
> hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/data/default/IntegrationTestBigLinkedList/b086e29f909c9790446cd457c1ea7674
> {code}
> However, it does not see ANY entry in the recovered.edits file
> {{0000000000000008752}}:
> {code}
> 2015-06-07 00:46:17,796 DEBUG
> [RS_OPEN_REGION-os-enis-dal-test-jun-4-5:16020-0] regionserver.HRegion:
> Applied 0, skipped 0, firstSequenceIdInLog=-1, maxSequenceIdInLog=-1,
> path=hdfs://os-enis-dal-test-jun-4-1.openstacklocal:8020/apps/hbase/data/data/default/IntegrationTestBigLinkedList/b086e29f909c9790446cd457c1ea7674/recovered.edits/0000000000000008752
> {code}
> Looking at the length of the file, it is very small which means that the
> edits are not written.
> Now, If you are still with me, I think the reason why we do not write any
> edit to {{0000000000000008752}} although we say we have written 739 edits is
> due to HBASE-12405.
> Specifically, we pass {{FSHLog.getEarliestMemstoreSeqNum() - 1}} as the
> stores flush seqId, which gets saved in the master and used with
> {{LastSequenceId}}.
> The WALSplitter skips the cells per store using {{filterCellByStore()}} which
> is logical. However, the data loss happens, because
> {{FSHLog.getEarliestMemstoreSeqNum()}} ignores flushing edits. For example,
> if we have seqId = 10 to 100 as flushing, and seqId 101 in the new memstore,
> and heartbeat to master during the flush will carry 101 as the earliest flush
> seqId. if the flush does not complete (due to RS getting killed) this results
> in incorrectly skipped edits.
> The WAL replay code also uses this kind of filtering so this may also explain
> some of the failures with DLR.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
