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https://issues.apache.org/jira/browse/HIVE-24291?focusedWorklogId=506564&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-506564
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ASF GitHub Bot logged work on HIVE-24291:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Oct/20 07:55
Start Date: 30/Oct/20 07:55
Worklog Time Spent: 10m
Work Description: pvargacl commented on a change in pull request #1592:
URL: https://github.com/apache/hive/pull/1592#discussion_r514923203
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
##########
@@ -1526,6 +1529,10 @@ private void
updateWSCommitIdAndCleanUpMetadata(Statement stmt, long txnid, TxnT
if (txnType == TxnType.MATER_VIEW_REBUILD) {
queryBatch.add("DELETE FROM \"MATERIALIZATION_REBUILD_LOCKS\" WHERE
\"MRL_TXN_ID\" = " + txnid);
}
+ if (txnType == TxnType.COMPACTION) {
Review comment:
I would prefer this method for two reasons:
1. To work correctly, the first point when we can update the CQ_NEXT_TXN_ID,
is inside the commitTxn, when we already have the lock for the txnId sequence.
Anywhere before that, there can be a txn, that will have a higher txnId than
the saved CQ_NEXT_TXN_ID and still not see the compaction as committed ->
causing the Cleaner to clean up deltas, that should be kept for that txn. So if
we don't do it in commitTxn, we only can do it after that, but that would mean,
that the update won't be part of the transaction, and can fail "silently"
2. In a follow up Jira, I need to provide a HMS notification for every
committed compaction, for that I would also need CQ_TXN_ID
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Issue Time Tracking
-------------------
Worklog Id: (was: 506564)
Time Spent: 1h (was: 50m)
> Compaction Cleaner prematurely cleans up deltas
> -----------------------------------------------
>
> Key: HIVE-24291
> URL: https://issues.apache.org/jira/browse/HIVE-24291
> Project: Hive
> Issue Type: Bug
> Reporter: Peter Varga
> Assignee: Peter Varga
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h
> Remaining Estimate: 0h
>
> Since HIVE-23107 the cleaner can clean up deltas that are still used by
> running queries.
> Example:
> * TxnId 1-5 writes to a partition, all commits
> * Compactor starts with txnId=6
> * Long running query starts with txnId=7, it sees txnId=6 as open in its
> snapshot
> * Compaction commits
> * Cleaner runs
> Previously min_history_level table would have prevented the Cleaner to delete
> the deltas1-5 until txnId=7 is open, but now they will be deleted and the
> long running query may fail if its tries to access the files.
> Solution could be to not run the cleaner until any txn is open that was
> opened before the compaction was committed (CQ_NEXT_TXN_ID)
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