[
https://issues.apache.org/jira/browse/HIVE-24291?focusedWorklogId=506626&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-506626
]
ASF GitHub Bot logged work on HIVE-24291:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Oct/20 10:12
Start Date: 30/Oct/20 10:12
Worklog Time Spent: 10m
Work Description: deniskuzZ commented on a change in pull request #1592:
URL: https://github.com/apache/hive/pull/1592#discussion_r514992535
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/CompactionTxnHandler.java
##########
@@ -1122,43 +1129,18 @@ public void setHadoopJobId(String hadoopJobId, long id)
{
@RetrySemantics.Idempotent
public long findMinOpenTxnIdForCleaner() throws MetaException{
Connection dbConn = null;
- Statement stmt = null;
- ResultSet rs = null;
try {
try {
dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED);
- stmt = dbConn.createStatement();
- String query = "SELECT COUNT(\"TXN_ID\") FROM \"TXNS\" WHERE
\"TXN_STATE\" = " + TxnStatus.OPEN;
- LOG.debug("Going to execute query <" + query + ">");
- rs = stmt.executeQuery(query);
- if (!rs.next()) {
- throw new MetaException("Transaction tables not properly
initialized.");
- }
- long numOpenTxns = rs.getLong(1);
- if (numOpenTxns > 0) {
- query = "SELECT MIN(\"RES\".\"ID\") FROM (" +
- "SELECT MIN(\"TXN_ID\") AS \"ID\" FROM \"TXNS\" WHERE
\"TXN_STATE\" = " + TxnStatus.OPEN +
- " UNION " +
- "SELECT MAX(\"CQ_NEXT_TXN_ID\") AS \"ID\" FROM
\"COMPACTION_QUEUE\" WHERE \"CQ_STATE\" = "
- + quoteChar(READY_FOR_CLEANING) +
- ") \"RES\"";
- } else {
- query = "SELECT MAX(\"TXN_ID\") + 1 FROM \"TXNS\"";
- }
- LOG.debug("Going to execute query <" + query + ">");
- rs = stmt.executeQuery(query);
- if (!rs.next()) {
- throw new MetaException("Transaction tables not properly
initialized, no record found in TXNS");
- }
- return rs.getLong(1);
+ return getMinOpenTxnIdWaterMark(dbConn);
Review comment:
What happens if TXNS table is empty?
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
Issue Time Tracking
-------------------
Worklog Id: (was: 506626)
Time Spent: 1h 40m (was: 1.5h)
> 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 40m
> 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)
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
