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https://issues.apache.org/jira/browse/HIVE-20627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16636420#comment-16636420
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Sankar Hariappan commented on HIVE-20627:
-----------------------------------------
[~pvary],
You are suggesting that, we shall maintain an Atomic reference counter in the
Hive object. We increment the counter when somebody sets it in thread local
hiveDb and decrement it when somebody releases it. Only when the counter is
down to 0, we should close the connection.
Couple of cases to release the thread local hiveDb:
* When synchronous query execution in master thread re-creates Hive object due
to config change. We also, need to update the sessionHive object in the current
session as we releases it from thread local hiveDb of master thread.
* When async thread exits after completing execution or due to exception.
If the session is getting closed, it is guaranteed that the reference counter
is down to 0 as we forcefully close all the async operations and so we can
close the connection there.
I think, this will work fine. I will create a Jira to incorporate this fix.
Please let me know if I missed anything.
cc [~daijy], [~thejas]
> Concurrent async queries intermittently fails with LockException and cause
> memory leak.
> ---------------------------------------------------------------------------------------
>
> Key: HIVE-20627
> URL: https://issues.apache.org/jira/browse/HIVE-20627
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2, Transactions
> Affects Versions: 4.0.0
> Reporter: Sankar Hariappan
> Assignee: Sankar Hariappan
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Attachments: HIVE-20627.01.patch
>
>
> When multiple async queries are executed from same session, it leads to
> multiple async query execution DAGs share the same Hive object which is set
> by caller for all threads. In case of loading dynamic partitions, it creates
> MoveTask which re-creates the Hive object and closes the shared Hive object
> which causes metastore connection issues for other async execution thread who
> still access it. This is also seen if ReplDumpTask and ReplLoadTask are part
> of the DAG.
> *Call Stack:*
> {code:java}
> 2018-09-16T04:38:04,280 ERROR [load-dynamic-partitions-7]: metadata.Hive
> (Hive.java:call(2436)) - Exception when loading partition with parameters
> partPath=hdfs://mycluster/warehouse/tablespace/managed/hive/tbl_3bcvvdubni/.hive-staging_hive_2018-09-16_04-35-50_708_7776079613819042057-1147/-ext-10000/age=55,
> table=tbl_3bcvvdubni, partSpec={age=55}, loadFileType=KEEP_EXISTING,
> listBucketingLevel=0, isAcid=true, hasFollowingStatsTask=true
> org.apache.hadoop.hive.ql.lockmgr.LockException: Error communicating with the
> metastore
> at
> org.apache.hadoop.hive.ql.lockmgr.DbTxnManager.getValidWriteIds(DbTxnManager.java:714)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.ql.io.AcidUtils.getTableValidWriteIdListWithTxnList(AcidUtils.java:1791)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.ql.io.AcidUtils.getTableSnapshot(AcidUtils.java:1756)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.ql.io.AcidUtils.getTableSnapshot(AcidUtils.java:1714)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at org.apache.hadoop.hive.ql.metadata.Hive.loadPartition(Hive.java:1976)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at org.apache.hadoop.hive.ql.metadata.Hive$5.call(Hive.java:2415)
> [hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at org.apache.hadoop.hive.ql.metadata.Hive$5.call(Hive.java:2406)
> [hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_171]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> [?:1.8.0_171]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> [?:1.8.0_171]
> at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]
> Caused by: org.apache.thrift.protocol.TProtocolException: Required field
> 'validTxnList' is unset!
> Struct:GetValidWriteIdsRequest(fullTableNames:[default.tbl_3bcvvdubni],
> validTxnList:null)
> at
> org.apache.hadoop.hive.metastore.api.GetValidWriteIdsRequest.validate(GetValidWriteIdsRequest.java:396)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_valid_write_ids_args.validate(ThriftHiveMetastore.java)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_valid_write_ids_args$get_valid_write_ids_argsStandardScheme.write(ThriftHiveMetastore.java)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_valid_write_ids_args$get_valid_write_ids_argsStandardScheme.write(ThriftHiveMetastore.java)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_valid_write_ids_args.write(ThriftHiveMetastore.java)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at org.apache.thrift.TServiceClient.sendBase(TServiceClient.java:71)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at org.apache.thrift.TServiceClient.sendBase(TServiceClient.java:62)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$Client.send_get_valid_write_ids(ThriftHiveMetastore.java:5443)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$Client.get_valid_write_ids(ThriftHiveMetastore.java:5435)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at
> org.apache.hadoop.hive.metastore.HiveMetaStoreClient.getValidWriteIds(HiveMetaStoreClient.java:2589)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at sun.reflect.GeneratedMethodAccessor125.invoke(Unknown Source) ~[?:?]
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> ~[?:1.8.0_171]
> at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_171]
> at
> org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.invoke(RetryingMetaStoreClient.java:212)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at com.sun.proxy.$Proxy57.getValidWriteIds(Unknown Source) ~[?:?]
> at sun.reflect.GeneratedMethodAccessor125.invoke(Unknown Source) ~[?:?]
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> ~[?:1.8.0_171]
> at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_171]
> at
> org.apache.hadoop.hive.metastore.HiveMetaStoreClient$SynchronizedHandler.invoke(HiveMetaStoreClient.java:2934)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> at com.sun.proxy.$Proxy57.getValidWriteIds(Unknown Source) ~[?:?]
> at
> org.apache.hadoop.hive.ql.lockmgr.DbTxnManager.getValidWriteIds(DbTxnManager.java:712)
> ~[hive-exec-3.1.0.3.0.1.0-184.jar:3.1.0.3.0.1.0-184]
> ... 10 more{code}
> *Root cause:*
> For Async query execution from SQLOperation.runInternal, we set the Thread
> local Hive object for all the child threads as parentHive
> (parentSession.getSessionHive())
> {code:java}
> @Override
> public void run() {
> PrivilegedExceptionAction<Object> doAsAction = new
> PrivilegedExceptionAction<Object>() {
> @Override
> public Object run() throws HiveSQLException {
> Hive.set(parentHive); // Setting parentHive for all async operations.
> // TODO: can this result in cross-thread reuse of session state?
> SessionState.setCurrentSessionState(parentSessionState);
> PerfLogger.setPerfLogger(parentPerfLogger);
> LogUtils.registerLoggingContext(queryState.getConf());
> try {
> if (asyncPrepare) {
> prepare(queryState);
> }
> runQuery();
> } catch (HiveSQLException e) {
> // TODO: why do we invent our own error path op top of the one from
> Future.get?
> setOperationException(e);
> LOG.error("Error running hive query: ", e);
> } finally {
> LogUtils.unregisterLoggingContext();
> }
> return null;
> }
> };
> {code}
> Now, when async execution in progress and if one of the thread re-creates the
> Hive object, it closes the parentHive object first which impacts other
> threads using it and hence conf object it refers too gets cleaned up and
> hence we get null for VALID_TXNS_KEY value.
> {code:java}
> private static Hive create(HiveConf c, boolean needsRefresh, Hive db, boolean
> doRegisterAllFns)
> throws HiveException {
> if (db != null) {
> LOG.debug("Creating new db. db = " + db + ", needsRefresh = " + needsRefresh
> +
> ", db.isCurrentUserOwner = " + db.isCurrentUserOwner());
> db.close();
> }
> closeCurrent();
> if (c == null) {
> c = createHiveConf();
> }
> c.set("fs.scheme.class", "dfs");
> Hive newdb = new Hive(c, doRegisterAllFns);
> hiveDB.set(newdb);
> return newdb;
> }
> {code}
> *Fix:*
> We shouldn't clean the old Hive object if it is shared by multiple threads.
> Shall use a flag to know this.
> *Memory leak issue:*
> Memory leak is found if one of the threads from Hive.loadDynamicPartitions
> throw exception. rawStoreMap is used to store rawStore objects which has to
> be cleaned. In this case, it is populated only in success flow but if there
> are exceptions, it is not and hence there is a leak.
> {code:java}
> futures.add(pool.submit(new Callable<Void>() {
> @Override
> public Void call() throws Exception {
> try {
> // move file would require session details (needCopy() invokes
> SessionState.get)
> SessionState.setCurrentSessionState(parentSession);
> LOG.info("New loading path = " + partPath + " with partSpec " +
> fullPartSpec);
> // load the partition
> Partition newPartition = loadPartition(partPath, tbl, fullPartSpec,
> loadFileType,
> true, false, numLB > 0, false, isAcid, hasFollowingStatsTask, writeId,
> stmtId,
> isInsertOverwrite);
> partitionsMap.put(fullPartSpec, newPartition);
> if (inPlaceEligible) {
> synchronized (ps) {
> InPlaceUpdate.rePositionCursor(ps);
> partitionsLoaded.incrementAndGet();
> InPlaceUpdate.reprintLine(ps, "Loaded : " + partitionsLoaded.get() + "/"
> + partsToLoad + " partitions.");
> }
> }
> // Add embedded rawstore, so we can cleanup later to avoid memory leak
> if (getMSC().isLocalMetaStore()) {
> if (!rawStoreMap.containsKey(Thread.currentThread().getId())) {
> rawStoreMap.put(Thread.currentThread().getId(),
> HiveMetaStore.HMSHandler.getRawStore());
> }
> }
> return null;
> } catch (Exception t) {
> }
> {code}
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