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https://issues.apache.org/jira/browse/HIVE-25113?focusedWorklogId=596918&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-596918
]
ASF GitHub Bot logged work on HIVE-25113:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 14/May/21 21:11
Start Date: 14/May/21 21:11
Worklog Time Spent: 10m
Work Description: kishendas commented on a change in pull request #2272:
URL: https://github.com/apache/hive/pull/2272#discussion_r632810253
##########
File path:
ql/src/test/org/apache/hadoop/hive/metastore/txn/TestTxnHandlerWithOneConnection.java
##########
@@ -0,0 +1,77 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hive.metastore.txn;
+
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.metastore.api.GetValidWriteIdsRequest;
+import org.apache.hadoop.hive.metastore.conf.MetastoreConf;
+import org.apache.hadoop.hive.metastore.utils.TestTxnDbUtil;
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.core.LoggerContext;
+import org.apache.logging.log4j.core.config.Configuration;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collections;
+
+/**
+ * Tests to ensure function works even with connection pool size is 1
+ */
+public class TestTxnHandlerWithOneConnection {
+ static final private String CLASS_NAME = TxnHandler.class.getName();
+ private static final Logger LOG = LoggerFactory.getLogger(CLASS_NAME);
+
+ private HiveConf conf = new HiveConf();
+ private TxnStore txnHandler;
+
+ public TestTxnHandlerWithOneConnection() throws Exception {
+ TestTxnDbUtil.setConfValues(conf);
+ TestTxnDbUtil.prepDb(conf);
+ LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
+ Configuration conf = ctx.getConfiguration();
+ conf.getLoggerConfig(CLASS_NAME).setLevel(Level.DEBUG);
+ ctx.updateLoggers(conf);
+ tearDown();
+ }
+
+ @Test
+ public void testGetValidWriteIds() throws Exception {
+ GetValidWriteIdsRequest req = new GetValidWriteIdsRequest();
+ req.setFullTableNames(Collections.singletonList("foo.bar"));
+ txnHandler.getValidWriteIds(req);
Review comment:
How are you verifying that same connection is reused ?
Don't you have to call multiple getValidWriteIds in parallel and make sure
they don't time out ?
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Issue Time Tracking
-------------------
Worklog Id: (was: 596918)
Time Spent: 1h 10m (was: 1h)
> Connection starvation in TxnHandler.getValidWriteIds
> ----------------------------------------------------
>
> Key: HIVE-25113
> URL: https://issues.apache.org/jira/browse/HIVE-25113
> Project: Hive
> Issue Type: Bug
> Components: Transactions
> Reporter: Yu-Wen Lai
> Assignee: Yu-Wen Lai
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
>
> The current code looks like below.
> {code:java}
> dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED);
> validTxnList = TxnUtils.createValidReadTxnList(getOpenTxns(), 0);
> {code}
> In the function getOpenTxns, it will request another connection from pool.
> That is, this thread already held a connection, however, it would request for
> another connection. When there are more than 10 (default connection pool
> size) simultaneous getValidWriteIds requests, it can cause a starvation
> problem. In that situation, each thread holds a connection and waits for
> another connection. Then, we will see the following exception after timeout.
> {code:java}
> metastore.RetryingHMSHandler: MetaException(message:Unable to select from
> transaction database, java.sql.SQLTransientConnectionException: HikariPool-3
> - Connection is not available, request timed out after 30000ms.{code}
>
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