[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-11-01 Thread Eugene Koifman (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16672392#comment-16672392
 ] 

Eugene Koifman commented on HIVE-18772:
---

patch 4 is a rebase of 3

> Make Acid Cleaner use MIN_HISTORY_LEVEL
> ---
>
> Key: HIVE-18772
> URL: https://issues.apache.org/jira/browse/HIVE-18772
> Project: Hive
>  Issue Type: Improvement
>  Components: Transactions
>Affects Versions: 3.0.0
>Reporter: Eugene Koifman
>Assignee: Eugene Koifman
>Priority: Major
> Attachments: HIVE-18772.01.patch, HIVE-18772.02.patch, 
> HIVE-18772.02.patch, HIVE-18772.03.patch, HIVE-18772.04.patch
>
>
> Instead of using Lock Manager state as it currently does.
> This will eliminate possible race conditions
> See this 
> [comment|https://issues.apache.org/jira/browse/HIVE-18192?focusedCommentId=16338208&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16338208]
> Suppose A is the set of all ValidTxnList across all active readers.  Each 
> ValidTxnList has minOpenTxnId.
> MIN_HISTORY_LEVEL allows us to determine X = min(minOpenTxnId) across all 
> currently active readers
> This means that no active transaction in the system sees any txn with txnid < 
> X as open.
> This means if construct ValidTxnIdList with HWM=X-1 and use that in 
> getAcidState(), any files determined by this call as 'obsolete', will be seen 
> as obsolete by any existing/future reader, i.e. can be physically deleted.
> This is also necessary for multi-statement transactions where relying on the 
> state of Lock Manager is not sufficient.  For example
> Suppose txn 17 starts at t1 and sees txnid 13 with writeID 13 open.
> 13 commits (via it's parent txn) at t2 > t1.  (17 is still running).
> Compaction runs at t3 >t2 to produce base_14 (or delta_10_14 for example) on 
> Table1/Part1 (17 is still running)
> Now delta_13 may be cleaned since it can be seen as obsolete and there may be 
> no locks on it, i.e. no one is reading it.
> Now at t4 > t3 17 may (multi stmt txn) needs to read Table1/Part1. It cannot 
> use base_14 is that may have absorbed delete events from delete_delta_14.
> Another Use Case
> There is delta_1_1 and delta_2_2 on disk both created by committed txns.
> T5 starts reading these.  At the same time compactor creates delta_1_2.
> Now Cleaner sees delta_1_1 and delta_1_2 as obsolete and may remove them 
> while the read is still in progress.  This is because Compactor itself is not 
> running in a txn and the files that
> it produces are visible immediately.  If it ran in a txn, the new files would 
> only be visible once
> this txn is visible to others (including the Cleaner).  
> Using MIN_HISTORY_LEVEL solves this.
> See description of HIVE-18747 for more details on MIN_HISTORY_LEVEL



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[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-09-05 Thread Hive QA (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16604371#comment-16604371
 ] 

Hive QA commented on HIVE-18772:




Here are the results of testing the latest attachment:
https://issues.apache.org/jira/secure/attachment/12938398/HIVE-18772.02.patch

{color:green}SUCCESS:{color} +1 due to 2 test(s) being added or modified.

{color:red}ERROR:{color} -1 due to 45 failed/errored test(s), 14921 tests 
executed
*Failed tests:*
{noformat}
org.apache.hadoop.hive.ql.TestTxnCommands2.testACIDwithSchemaEvolutionAndCompaction
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testCleanerForTxnToWriteId 
(batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testInitiatorWithMultipleFailedCompactions
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testInsertOverwrite1 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testInsertOverwrite2 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testNonAcidToAcidConversion1 
(batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testNonAcidToAcidConversion2 
(batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2.testNonAcidToAcidConversion3 
(batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testACIDwithSchemaEvolutionAndCompaction
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testCleanerForTxnToWriteId
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testInitiatorWithMultipleFailedCompactions
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testInsertOverwrite1
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testInsertOverwrite2
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testNonAcidToAcidConversion1
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testNonAcidToAcidConversion2
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommands2WithSplitUpdateAndVectorization.testNonAcidToAcidConversion3
 (batchId=310)
org.apache.hadoop.hive.ql.TestTxnCommandsForMmTable.testInsertOverwriteForPartitionedMmTable
 (batchId=275)
org.apache.hadoop.hive.ql.TestTxnCommandsForMmTable.testInsertOverwriteWithUnionAll
 (batchId=275)
org.apache.hadoop.hive.ql.TestTxnCommandsForMmTable.testOperationsOnCompletedTxnComponentsForMmTable
 (batchId=275)
org.apache.hadoop.hive.ql.TestTxnCommandsForMmTable.testSnapshotIsolationWithAbortedTxnOnMmTable
 (batchId=275)
org.apache.hadoop.hive.ql.TestTxnCommandsForOrcMmTable.testInsertOverwriteForPartitionedMmTable
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommandsForOrcMmTable.testInsertOverwriteWithUnionAll
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommandsForOrcMmTable.testOperationsOnCompletedTxnComponentsForMmTable
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnCommandsForOrcMmTable.testSnapshotIsolationWithAbortedTxnOnMmTable
 (batchId=297)
org.apache.hadoop.hive.ql.TestTxnNoBuckets.testNoBuckets (batchId=297)
org.apache.hadoop.hive.ql.TestTxnNoBucketsVectorized.testNoBuckets (batchId=299)
org.apache.hadoop.hive.ql.lockmgr.TestDbTxnManager2.testMetastoreTablesCleanup 
(batchId=314)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.cleanupAfterMajorPartitionCompaction
 (batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.cleanupAfterMajorPartitionCompactionNoBase
 (batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.cleanupAfterMajorTableCompaction
 (batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.cleanupAfterMinorPartitionCompaction
 (batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.cleanupAfterMinorTableCompaction
 (batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.cleanupAfterMajorPartitionCompaction
 (batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.cleanupAfterMajorPartitionCompactionNoBase
 (batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.cleanupAfterMajorTableCompaction
 (batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.cleanupAfterMinorPartitionCompaction
 (batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.cleanupAfterMinorTableCompaction
 (batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleanerWithReplication.cleanupAfterMajorPartitionCompaction
 (batchId=241)
org.apache.hadoop.hive.ql.txn.compactor.TestCleanerWithReplication.cleanupAfterMajorTableCompaction
 (batchId=241)
org.apache.hadoop.hive.ql.txn.compactor.TestCleanerWithReplication.cleanupAfterMinorPartitionCompaction
 (batchId=241)
org.apache.hadoop.hive.ql.txn.compactor.TestCleanerWithReplication.cleanupAfterMinorTableCompaction
 (batchId=241)
org.apache.hadoop.hive.ql.txn.compactor.TestCompactor.mmTableOpenWriteId[0] 
(batchId=240)
org.apache.hadoop.hive.ql.txn.compactor.TestCompacto

[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-09-05 Thread Hive QA (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16604336#comment-16604336
 ] 

Hive QA commented on HIVE-18772:


| (x) *{color:red}-1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
|| || || || {color:brown} Prechecks {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:brown} master Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m 
23s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  8m 
35s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 
35s{color} | {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  0m 
53s{color} | {color:green} master passed {color} |
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue}  4m  
9s{color} | {color:blue} ql in master has 2310 extant Findbugs warnings. 
{color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red}  0m 
15s{color} | {color:red} metastore-server in master failed. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  1m 
22s{color} | {color:green} master passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m  
9s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:red}-1{color} | {color:red} mvninstall {color} | {color:red}  0m 
57s{color} | {color:red} ql in the patch failed. {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 
32s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green}  1m 
32s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} checkstyle {color} | {color:red}  0m 
45s{color} | {color:red} ql: The patch generated 16 new + 549 unchanged - 2 
fixed = 565 total (was 551) {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green}  0m 
 0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red}  4m 
25s{color} | {color:red} ql generated 1 new + 2309 unchanged - 1 fixed = 2310 
total (was 2310) {color} |
| {color:red}-1{color} | {color:red} findbugs {color} | {color:red}  0m 
15s{color} | {color:red} metastore-server in the patch failed. {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  1m 
23s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green}  0m 
15s{color} | {color:green} The patch does not generate ASF License warnings. 
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 28m  3s{color} | 
{color:black} {color} |
\\
\\
|| Reason || Tests ||
| FindBugs | module:ql |
|  |  Exception is caught when Exception is not thrown in 
org.apache.hadoop.hive.ql.txn.compactor.Cleaner.clean(CompactionInfo, Long)  At 
Cleaner.java:is not thrown in 
org.apache.hadoop.hive.ql.txn.compactor.Cleaner.clean(CompactionInfo, Long)  At 
Cleaner.java:[line 218] |
\\
\\
|| Subsystem || Report/Notes ||
| Optional Tests |  asflicense  javac  javadoc  findbugs  checkstyle  compile  |
| uname | Linux hiveptest-server-upstream 3.16.0-4-amd64 #1 SMP Debian 
3.16.36-1+deb8u1 (2016-09-03) x86_64 GNU/Linux |
| Build tool | maven |
| Personality | 
/data/hiveptest/working/yetus_PreCommit-HIVE-Build-13598/dev-support/hive-personality.sh
 |
| git revision | master / 154ca3e |
| Default Java | 1.8.0_111 |
| findbugs | v3.0.0 |
| findbugs | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus/branch-findbugs-standalone-metastore_metastore-server.txt
 |
| mvninstall | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus/patch-mvninstall-ql.txt
 |
| checkstyle | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus/diff-checkstyle-ql.txt
 |
| findbugs | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus/new-findbugs-ql.html
 |
| findbugs | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus/patch-findbugs-standalone-metastore_metastore-server.txt
 |
| modules | C: ql standalone-metastore/metastore-server U: . |
| Console output | 
http://104.198.109.242/logs//PreCommit-HIVE-Build-13598/yetus.txt |
| Powered by | Apache Yetushttp://yetus.apache.org |


This message was automatically generated.



> Make Acid Cleaner use MIN_HISTORY_LEVEL
>

[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-08-25 Thread Hive QA (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16592531#comment-16592531
 ] 

Hive QA commented on HIVE-18772:




Here are the results of testing the latest attachment:
https://issues.apache.org/jira/secure/attachment/12937099/HIVE-18772.01.patch

{color:red}ERROR:{color} -1 due to no test(s) being added or modified.

{color:red}ERROR:{color} -1 due to 4 failed/errored test(s), 14896 tests 
executed
*Failed tests:*
{noformat}
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.blockedByLockPartition 
(batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner.blockedByLockTable 
(batchId=284)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.blockedByLockPartition 
(batchId=285)
org.apache.hadoop.hive.ql.txn.compactor.TestCleaner2.blockedByLockTable 
(batchId=285)
{noformat}

Test results: 
https://builds.apache.org/job/PreCommit-HIVE-Build/13466/testReport
Console output: https://builds.apache.org/job/PreCommit-HIVE-Build/13466/console
Test logs: http://104.198.109.242/logs/PreCommit-HIVE-Build-13466/

Messages:
{noformat}
Executing org.apache.hive.ptest.execution.TestCheckPhase
Executing org.apache.hive.ptest.execution.PrepPhase
Executing org.apache.hive.ptest.execution.YetusPhase
Executing org.apache.hive.ptest.execution.ExecutionPhase
Executing org.apache.hive.ptest.execution.ReportingPhase
Tests exited with: TestsFailedException: 4 tests failed
{noformat}

This message is automatically generated.

ATTACHMENT ID: 12937099 - PreCommit-HIVE-Build

> Make Acid Cleaner use MIN_HISTORY_LEVEL
> ---
>
> Key: HIVE-18772
> URL: https://issues.apache.org/jira/browse/HIVE-18772
> Project: Hive
>  Issue Type: Improvement
>  Components: Transactions
>Affects Versions: 3.0.0
>Reporter: Eugene Koifman
>Assignee: Eugene Koifman
>Priority: Major
> Attachments: HIVE-18772.01.patch
>
>
> Instead of using Lock Manager state as it currently does.
> This will eliminate possible race conditions
> See this 
> [comment|https://issues.apache.org/jira/browse/HIVE-18192?focusedCommentId=16338208&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16338208]
> Suppose A is the set of all ValidTxnList across all active readers.  Each 
> ValidTxnList has minOpenTxnId.
> MIN_HISTORY_LEVEL allows us to determine X = min(minOpenTxnId) across all 
> currently active readers
> This means that no active transaction in the system sees any txn with txnid < 
> X as open.
> This means if construct ValidTxnIdList with HWM=X-1 and use that in 
> getAcidState(), any files determined by this call as 'obsolete', will be seen 
> as obsolete by any existing/future reader, i.e. can be physically deleted.
> This is also necessary for multi-statement transactions where relying on the 
> state of Lock Manager is not sufficient.  For example
> Suppose txn 17 starts at t1 and sees txnid 13 with writeID 13 open.
> 13 commits (via it's parent txn) at t2 > t1.  (17 is still running).
> Compaction runs at t3 >t2 to produce base_14 (or delta_10_14 for example) on 
> Table1/Part1 (17 is still running)
> Now delta_13 may be cleaned since it can be seen as obsolete and there may be 
> no locks on it, i.e. no one is reading it.
> Now at t4 > t3 17 may (multi stmt txn) needs to read Table1/Part1. It cannot 
> use base_14 is that may have absorbed delete events from delete_delta_14.
> Using MIN_HISTORY_LEVEL solves this.
> See description of HIVE-18747 for more details on MIN_HISTORY_LEVEL



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[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-08-24 Thread Eugene Koifman (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16592292#comment-16592292
 ] 

Eugene Koifman commented on HIVE-18772:
---

HIVE-20459 would be nice to have here

> Make Acid Cleaner use MIN_HISTORY_LEVEL
> ---
>
> Key: HIVE-18772
> URL: https://issues.apache.org/jira/browse/HIVE-18772
> Project: Hive
>  Issue Type: Improvement
>  Components: Transactions
>Affects Versions: 3.0.0
>Reporter: Eugene Koifman
>Assignee: Eugene Koifman
>Priority: Major
>
> Instead of using Lock Manager state as it currently does.
> This will eliminate possible race conditions
> See this 
> [comment|https://issues.apache.org/jira/browse/HIVE-18192?focusedCommentId=16338208&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16338208]
> Suppose A is the set of all ValidTxnList across all active readers.  Each 
> ValidTxnList has minOpenTxnId.
> MIN_HISTORY_LEVEL allows us to determine X = min(minOpenTxnId) across all 
> currently active readers
> This means that no active transaction in the system sees any txn with txnid < 
> X as open.
> This means if construct ValidTxnIdList with HWM=X-1 and use that in 
> getAcidState(), any files determined by this call as 'obsolete', will be seen 
> as obsolete by any existing/future reader, i.e. can be physically deleted.
> This is also necessary for multi-statement transactions where relying on the 
> state of Lock Manager is not sufficient.  For example
> Suppose txn 17 starts at t1 and sees txnid 13 with writeID 13 open.
> 13 commits (via it's parent txn) at t2 > t1.  (17 is still running).
> Compaction runs at t3 >t2 to produce base_14 (or delta_10_14 for example) on 
> Table1/Part1 (17 is still running)
> Now delta_13 may be cleaned since it can be seen as obsolete and there may be 
> no locks on it, i.e. no one is reading it.
> Now at t4 > t3 17 may (multi stmt txn) needs to read Table1/Part1. It cannot 
> use base_14 is that may have absorbed delete events from delete_delta_14.
> Using MIN_HISTORY_LEVEL solves this.
> See description of HIVE-18747 for more details on MIN_HISTORY_LEVEL



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[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-08-23 Thread Sankar Hariappan (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16590579#comment-16590579
 ] 

Sankar Hariappan commented on HIVE-18772:
-

[~ekoifman], no impact on replication as we run ACID compaction and cleaner at 
target cluster itself.

> Make Acid Cleaner use MIN_HISTORY_LEVEL
> ---
>
> Key: HIVE-18772
> URL: https://issues.apache.org/jira/browse/HIVE-18772
> Project: Hive
>  Issue Type: Improvement
>  Components: Transactions
>Affects Versions: 3.0.0
>Reporter: Eugene Koifman
>Assignee: Eugene Koifman
>Priority: Major
>
> Instead of using Lock Manager state as it currently does.
> This will eliminate possible race conditions
> See this 
> [comment|https://issues.apache.org/jira/browse/HIVE-18192?focusedCommentId=16338208&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16338208]
> Suppose A is the set of all ValidTxnList across all active readers.  Each 
> ValidTxnList has minOpenTxnId.
> MIN_HISTORY_LEVEL allows us to determine X = min(minOpenTxnId) across all 
> currently active readers
> This means that no active transaction in the system sees any txn with txnid < 
> X as open.
> This means if construct ValidTxnIdList with HWM=X-1 and use that in 
> getAcidState(), any files determined by this call as 'obsolete', will be seen 
> as obsolete by any existing/future reader, i.e. can be physically deleted.
> This is also necessary for multi-statement transactions where relying on the 
> state of Lock Manager is not sufficient.  For example
> Suppose txn 17 starts at t1 and sees txnid 13 with writeID 13 open.
> 13 commits (via it's parent txn) at t2 > t1.  (17 is still running).
> Compaction runs at t3 >t2 to produce base_14 (or delta_10_14 for example) on 
> Table1/Part1 (17 is still running)
> Now delta_13 may be cleaned since it can be seen as obsolete and there may be 
> no locks on it, i.e. no one is reading it.
> Now at t4 > t3 17 may (multi stmt txn) needs to read Table1/Part1. It cannot 
> use base_14 is that may have absorbed delete events from delete_delta_14.
> Using MIN_HISTORY_LEVEL solves this.
> See description of HIVE-18747 for more details on MIN_HISTORY_LEVEL



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[jira] [Commented] (HIVE-18772) Make Acid Cleaner use MIN_HISTORY_LEVEL

2018-08-23 Thread Eugene Koifman (JIRA) 


[ 
https://issues.apache.org/jira/browse/HIVE-18772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16590496#comment-16590496
 ] 

Eugene Koifman commented on HIVE-18772:
---

[~sankarh], would this have any impact on replication?

> Make Acid Cleaner use MIN_HISTORY_LEVEL
> ---
>
> Key: HIVE-18772
> URL: https://issues.apache.org/jira/browse/HIVE-18772
> Project: Hive
>  Issue Type: Improvement
>  Components: Transactions
>Affects Versions: 3.0.0
>Reporter: Eugene Koifman
>Assignee: Eugene Koifman
>Priority: Major
>
> Instead of using Lock Manager state as it currently does.
> This will eliminate possible race conditions
> See this 
> [comment|https://issues.apache.org/jira/browse/HIVE-18192?focusedCommentId=16338208&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16338208]
> Suppose A is the set of all ValidTxnList across all active readers.  Each 
> ValidTxnList has minOpenTxnId.
> MIN_HISTORY_LEVEL allows us to determine X = min(minOpenTxnId) across all 
> currently active readers
> This means that no active transaction in the system sees any txn with txnid < 
> X as open.
> This means if construct ValidTxnIdList with HWM=X-1 and use that in 
> getAcidState(), any files determined by this call as 'obsolete', will be seen 
> as obsolete by any existing/future reader, i.e. can be physically deleted.
> This is also necessary for multi-statement transactions where relying on the 
> state of Lock Manager is not sufficient.  For example
> Suppose txn 17 starts at t1 and sees txnid 13 with writeID 13 open.
> 13 commits (via it's parent txn) at t2 > t1.  (17 is still running).
> Compaction runs at t3 >t2 to produce base_14 (or delta_10_14 for example) on 
> Table1/Part1 (17 is still running)
> Now delta_13 may be cleaned since it can be seen as obsolete and there may be 
> no locks on it, i.e. no one is reading it.
> Now at t4 > t3 17 may (multi stmt txn) needs to read Table1/Part1. It cannot 
> use base_14 is that may have absorbed delete events from delete_delta_14.
> Using MIN_HISTORY_LEVEL solves this.
> See description of HIVE-18747 for more details on MIN_HISTORY_LEVEL



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