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Hadoop QA commented on HBASE-21387: ----------------------------------- | (/) *{color:green}+1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || | {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m 11s{color} | {color:blue} Docker mode activated. {color} | || || || || {color:brown} Prechecks {color} || | {color:green}+1{color} | {color:green} hbaseanti {color} | {color:green} 0m 0s{color} | {color:green} Patch does not have any anti-patterns. {color} | | {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s{color} | {color:green} The patch does not contain any @author tags. {color} | | {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m 0s{color} | {color:green} The patch appears to include 3 new or modified test files. {color} | || || || || {color:brown} master Compile Tests {color} || | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 3m 55s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 42s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 1s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} shadedjars {color} | {color:green} 3m 39s{color} | {color:green} branch has no errors when building our shaded downstream artifacts. {color} | | {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m 54s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 27s{color} | {color:green} master passed {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 3m 48s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 45s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m 45s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 7s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m 0s{color} | {color:green} The patch has no whitespace issues. {color} | | {color:green}+1{color} | {color:green} shadedjars {color} | {color:green} 3m 39s{color} | {color:green} patch has no errors when building our shaded downstream artifacts. {color} | | {color:green}+1{color} | {color:green} hadoopcheck {color} | {color:green} 7m 59s{color} | {color:green} Patch does not cause any errors with Hadoop 2.7.4 or 3.0.0. {color} | | {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 2m 5s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 26s{color} | {color:green} the patch passed {color} | || || || || {color:brown} Other Tests {color} || | {color:green}+1{color} | {color:green} unit {color} | {color:green}128m 36s{color} | {color:green} hbase-server in the patch passed. {color} | | {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 19s{color} | {color:green} The patch does not generate ASF License warnings. {color} | | {color:black}{color} | {color:black} {color} | {color:black}163m 1s{color} | {color:black} {color} | \\ \\ || Subsystem || Report/Notes || | Docker | Client=17.05.0-ce Server=17.05.0-ce Image:yetus/hbase:b002b0b | | JIRA Issue | HBASE-21387 | | JIRA Patch URL | https://issues.apache.org/jira/secure/attachment/12949008/HBASE-21387.v16.patch | | Optional Tests | dupname asflicense javac javadoc unit findbugs shadedjars hadoopcheck hbaseanti checkstyle compile | | uname | Linux 9a043d0a42da 4.4.0-138-generic #164-Ubuntu SMP Tue Oct 2 17:16:02 UTC 2018 x86_64 GNU/Linux | | Build tool | maven | | Personality | /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build/component/dev-support/hbase-personality.sh | | git revision | master / 5ded294419 | | maven | version: Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T18:33:14Z) | | Default Java | 1.8.0_181 | | findbugs | v3.1.0-RC3 | | Test Results | https://builds.apache.org/job/PreCommit-HBASE-Build/15084/testReport/ | | Max. process+thread count | 5181 (vs. ulimit of 10000) | | modules | C: hbase-server U: hbase-server | | Console output | https://builds.apache.org/job/PreCommit-HBASE-Build/15084/console | | Powered by | Apache Yetus 0.8.0 http://yetus.apache.org | This message was automatically generated. > Race condition surrounding in progress snapshot handling in snapshot cache > leads to loss of snapshot files > ---------------------------------------------------------------------------------------------------------- > > Key: HBASE-21387 > URL: https://issues.apache.org/jira/browse/HBASE-21387 > Project: HBase > Issue Type: Bug > Reporter: Ted Yu > Assignee: Ted Yu > Priority: Major > Labels: snapshot > Attachments: 0001-UT.patch, 21387.dbg.txt, 21387.v10.txt, > 21387.v11.txt, 21387.v12.txt, 21387.v2.txt, 21387.v3.txt, 21387.v6.txt, > 21387.v7.txt, 21387.v8.txt, 21387.v9.txt, HBASE-21387.v13.patch, > HBASE-21387.v14.patch, HBASE-21387.v15.patch, HBASE-21387.v16.patch, > two-pass-cleaner.v4.txt, two-pass-cleaner.v6.txt, two-pass-cleaner.v9.txt > > > During recent report from customer where ExportSnapshot failed: > {code} > 2018-10-09 18:54:32,559 ERROR [VerifySnapshot-pool1-t2] > snapshot.SnapshotReferenceUtil: Can't find hfile: > 44f6c3c646e84de6a63fe30da4fcb3aa in the real > (hdfs://in.com:8020/apps/hbase/data/data/.../a/44f6c3c646e84de6a63fe30da4fcb3aa) > or archive > (hdfs://in.com:8020/apps/hbase/data/archive/data/.../a/44f6c3c646e84de6a63fe30da4fcb3aa) > directory for the primary table. > {code} > We found the following in log: > {code} > 2018-10-09 18:54:23,675 DEBUG > [00:16000.activeMasterManager-HFileCleaner.large-1539035367427] > cleaner.HFileCleaner: Removing: > hdfs:///apps/hbase/data/archive/data/.../a/44f6c3c646e84de6a63fe30da4fcb3aa > from archive > {code} > The root cause is race condition surrounding in progress snapshot(s) handling > between refreshCache() and getUnreferencedFiles(). > There are two callers of refreshCache: one from RefreshCacheTask#run and the > other from SnapshotHFileCleaner. > Let's look at the code of refreshCache: > {code} > if (!name.equals(SnapshotDescriptionUtils.SNAPSHOT_TMP_DIR_NAME)) { > {code} > whose intention is to exclude in progress snapshot(s). > Suppose when the RefreshCacheTask runs refreshCache, there is some in > progress snapshot (about to finish). > When SnapshotHFileCleaner calls getUnreferencedFiles(), it sees that > lastModifiedTime is up to date. So cleaner proceeds to check in progress > snapshot(s). However, the snapshot has completed by that time, resulting in > some file(s) deemed unreferenced. > Here is timeline given by Josh illustrating the scenario: > At time T0, we are checking if F1 is referenced. At time T1, there is a > snapshot S1 in progress that is referencing a file F1. refreshCache() is > called, but no completed snapshot references F1. At T2, the snapshot S1, > which references F1, completes. At T3, we check in-progress snapshots and S1 > is not included. Thus, F1 is marked as unreferenced even though S1 references > it. -- This message was sent by Atlassian JIRA (v7.6.3#76005)