-
Notifications
You must be signed in to change notification settings - Fork 4.6k
/
HiveStatement.java
853 lines (738 loc) · 21.8 KB
/
HiveStatement.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
/**
* 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.hive.jdbc;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.SQLWarning;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.hive.service.cli.RowSet;
import org.apache.hive.service.cli.RowSetFactory;
import org.apache.hive.service.cli.thrift.TCLIService;
import org.apache.hive.service.cli.thrift.TCancelOperationReq;
import org.apache.hive.service.cli.thrift.TCancelOperationResp;
import org.apache.hive.service.cli.thrift.TCloseOperationReq;
import org.apache.hive.service.cli.thrift.TCloseOperationResp;
import org.apache.hive.service.cli.thrift.TExecuteStatementReq;
import org.apache.hive.service.cli.thrift.TExecuteStatementResp;
import org.apache.hive.service.cli.thrift.TGetOperationStatusReq;
import org.apache.hive.service.cli.thrift.TGetOperationStatusResp;
import org.apache.hive.service.cli.thrift.TOperationHandle;
import org.apache.hive.service.cli.thrift.TSessionHandle;
import org.apache.hive.service.cli.thrift.TFetchResultsReq;
import org.apache.hive.service.cli.thrift.TFetchResultsResp;
import org.apache.hive.service.cli.thrift.TFetchOrientation;
/**
* HiveStatement.
*
*/
public class HiveStatement implements java.sql.Statement {
private final HiveConnection connection;
private TCLIService.Iface client;
private TOperationHandle stmtHandle = null;
private final TSessionHandle sessHandle;
Map<String,String> sessConf = new HashMap<String,String>();
private int fetchSize = 50;
private boolean isScrollableResultset = false;
/**
* We need to keep a reference to the result set to support the following:
* <code>
* statement.execute(String sql);
* statement.getResultSet();
* </code>.
*/
private ResultSet resultSet = null;
/**
* Sets the limit for the maximum number of rows that any ResultSet object produced by this
* Statement can contain to the given number. If the limit is exceeded, the excess rows
* are silently dropped. The value must be >= 0, and 0 means there is not limit.
*/
private int maxRows = 0;
/**
* Add SQLWarnings to the warningChain if needed.
*/
private SQLWarning warningChain = null;
/**
* Keep state so we can fail certain calls made after close().
*/
private boolean isClosed = false;
/**
* Keep state so we can fail certain calls made after cancel().
*/
private boolean isCancelled = false;
/**
* Keep this state so we can know whether the query in this statement is closed.
*/
private boolean isQueryClosed = false;
/**
* Keep this state so we can know whether the query logs are being generated in HS2.
*/
private boolean isLogBeingGenerated = true;
/**
* Keep this state so we can know whether the statement is submitted to HS2 and start execution
* successfully.
*/
private boolean isExecuteStatementFailed = false;
// A fair reentrant lock
private ReentrantLock transportLock = new ReentrantLock(true);
public HiveStatement(HiveConnection connection, TCLIService.Iface client,
TSessionHandle sessHandle) {
this(connection, client, sessHandle, false);
}
public HiveStatement(HiveConnection connection, TCLIService.Iface client,
TSessionHandle sessHandle, boolean isScrollableResultset) {
this.connection = connection;
this.client = client;
this.sessHandle = sessHandle;
this.isScrollableResultset = isScrollableResultset;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#addBatch(java.lang.String)
*/
@Override
public void addBatch(String sql) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#cancel()
*/
@Override
public void cancel() throws SQLException {
checkConnection("cancel");
if (isCancelled) {
return;
}
transportLock.lock();
try {
if (stmtHandle != null) {
TCancelOperationReq cancelReq = new TCancelOperationReq(stmtHandle);
TCancelOperationResp cancelResp = client.CancelOperation(cancelReq);
Utils.verifySuccessWithInfo(cancelResp.getStatus());
}
} catch (SQLException e) {
throw e;
} catch (Exception e) {
throw new SQLException(e.toString(), "08S01", e);
} finally {
transportLock.unlock();
}
isCancelled = true;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#clearBatch()
*/
@Override
public void clearBatch() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#clearWarnings()
*/
@Override
public void clearWarnings() throws SQLException {
warningChain = null;
}
void closeClientOperation() throws SQLException {
transportLock.lock();
try {
if (stmtHandle != null) {
TCloseOperationReq closeReq = new TCloseOperationReq(stmtHandle);
TCloseOperationResp closeResp = client.CloseOperation(closeReq);
Utils.verifySuccessWithInfo(closeResp.getStatus());
}
} catch (SQLException e) {
throw e;
} catch (Exception e) {
throw new SQLException(e.toString(), "08S01", e);
} finally {
transportLock.unlock();
}
isQueryClosed = true;
isExecuteStatementFailed = false;
stmtHandle = null;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#close()
*/
@Override
public void close() throws SQLException {
if (isClosed) {
return;
}
closeClientOperation();
client = null;
resultSet = null;
isClosed = true;
}
// JDK 1.7
public void closeOnCompletion() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#execute(java.lang.String)
*/
@Override
public boolean execute(String sql) throws SQLException {
checkConnection("execute");
closeClientOperation();
initFlags();
TExecuteStatementReq execReq = new TExecuteStatementReq(sessHandle, sql);
/**
* Run asynchronously whenever possible
* Currently only a SQLOperation can be run asynchronously,
* in a background operation thread
* Compilation is synchronous and execution is asynchronous
*/
execReq.setRunAsync(true);
execReq.setConfOverlay(sessConf);
transportLock.lock();
try {
TExecuteStatementResp execResp = client.ExecuteStatement(execReq);
Utils.verifySuccessWithInfo(execResp.getStatus());
stmtHandle = execResp.getOperationHandle();
isExecuteStatementFailed = false;
} catch (SQLException eS) {
isExecuteStatementFailed = true;
throw eS;
} catch (Exception ex) {
isExecuteStatementFailed = true;
throw new SQLException(ex.toString(), "08S01", ex);
} finally {
transportLock.unlock();
}
TGetOperationStatusReq statusReq = new TGetOperationStatusReq(stmtHandle);
boolean operationComplete = false;
TGetOperationStatusResp statusResp;
// Poll on the operation status, till the operation is complete
while (!operationComplete) {
try {
/**
* For an async SQLOperation, GetOperationStatus will use the long polling approach
* It will essentially return after the HIVE_SERVER2_LONG_POLLING_TIMEOUT (a server config) expires
*/
transportLock.lock();
try {
statusResp = client.GetOperationStatus(statusReq);
} finally {
transportLock.unlock();
}
Utils.verifySuccessWithInfo(statusResp.getStatus());
if (statusResp.isSetOperationState()) {
switch (statusResp.getOperationState()) {
case CLOSED_STATE:
case FINISHED_STATE:
operationComplete = true;
break;
case CANCELED_STATE:
// 01000 -> warning
throw new SQLException("Query was cancelled", "01000");
case ERROR_STATE:
// Get the error details from the underlying exception
throw new SQLException(statusResp.getErrorMessage(),
statusResp.getSqlState(), statusResp.getErrorCode());
case UKNOWN_STATE:
throw new SQLException("Unknown query", "HY000");
case INITIALIZED_STATE:
case PENDING_STATE:
case RUNNING_STATE:
break;
}
}
} catch (SQLException e) {
isLogBeingGenerated = false;
throw e;
} catch (Exception e) {
isLogBeingGenerated = false;
throw new SQLException(e.toString(), "08S01", e);
}
}
isLogBeingGenerated = false;
// The query should be completed by now
if (!stmtHandle.isHasResultSet()) {
return false;
}
resultSet = new HiveQueryResultSet.Builder(this).setClient(client).setSessionHandle(sessHandle)
.setStmtHandle(stmtHandle).setMaxRows(maxRows).setFetchSize(fetchSize)
.setScrollable(isScrollableResultset).setTransportLock(transportLock)
.build();
return true;
}
private void checkConnection(String action) throws SQLException {
if (isClosed) {
throw new SQLException("Can't " + action + " after statement has been closed");
}
}
private void initFlags() {
isCancelled = false;
isQueryClosed = false;
isLogBeingGenerated = true;
isExecuteStatementFailed = false;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#execute(java.lang.String, int)
*/
@Override
public boolean execute(String sql, int autoGeneratedKeys) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#execute(java.lang.String, int[])
*/
@Override
public boolean execute(String sql, int[] columnIndexes) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#execute(java.lang.String, java.lang.String[])
*/
@Override
public boolean execute(String sql, String[] columnNames) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeBatch()
*/
@Override
public int[] executeBatch() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeQuery(java.lang.String)
*/
@Override
public ResultSet executeQuery(String sql) throws SQLException {
if (!execute(sql)) {
throw new SQLException("The query did not generate a result set!");
}
return resultSet;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeUpdate(java.lang.String)
*/
@Override
public int executeUpdate(String sql) throws SQLException {
execute(sql);
return 0;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeUpdate(java.lang.String, int)
*/
@Override
public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeUpdate(java.lang.String, int[])
*/
@Override
public int executeUpdate(String sql, int[] columnIndexes) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#executeUpdate(java.lang.String, java.lang.String[])
*/
@Override
public int executeUpdate(String sql, String[] columnNames) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getConnection()
*/
@Override
public Connection getConnection() throws SQLException {
checkConnection("getConnection");
return this.connection;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getFetchDirection()
*/
@Override
public int getFetchDirection() throws SQLException {
checkConnection("getFetchDirection");
return ResultSet.FETCH_FORWARD;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getFetchSize()
*/
@Override
public int getFetchSize() throws SQLException {
checkConnection("getFetchSize");
return fetchSize;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getGeneratedKeys()
*/
@Override
public ResultSet getGeneratedKeys() throws SQLException {
throw new SQLFeatureNotSupportedException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getMaxFieldSize()
*/
@Override
public int getMaxFieldSize() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getMaxRows()
*/
@Override
public int getMaxRows() throws SQLException {
checkConnection("getMaxRows");
return maxRows;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getMoreResults()
*/
@Override
public boolean getMoreResults() throws SQLException {
return false;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getMoreResults(int)
*/
@Override
public boolean getMoreResults(int current) throws SQLException {
throw new SQLFeatureNotSupportedException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getQueryTimeout()
*/
@Override
public int getQueryTimeout() throws SQLException {
checkConnection("getQueryTimeout");
return 0;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getResultSet()
*/
@Override
public ResultSet getResultSet() throws SQLException {
checkConnection("getResultSet");
return resultSet;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getResultSetConcurrency()
*/
@Override
public int getResultSetConcurrency() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getResultSetHoldability()
*/
@Override
public int getResultSetHoldability() throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getResultSetType()
*/
@Override
public int getResultSetType() throws SQLException {
checkConnection("getResultSetType");
return ResultSet.TYPE_FORWARD_ONLY;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getUpdateCount()
*/
@Override
public int getUpdateCount() throws SQLException {
checkConnection("getUpdateCount");
return -1;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#getWarnings()
*/
@Override
public SQLWarning getWarnings() throws SQLException {
checkConnection("getWarnings");
return warningChain;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#isClosed()
*/
@Override
public boolean isClosed() throws SQLException {
return isClosed;
}
// JDK 1.7
public boolean isCloseOnCompletion() throws SQLException {
return false;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#isPoolable()
*/
@Override
public boolean isPoolable() throws SQLException {
return false;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setCursorName(java.lang.String)
*/
@Override
public void setCursorName(String name) throws SQLException {
throw new SQLFeatureNotSupportedException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setEscapeProcessing(boolean)
*/
@Override
public void setEscapeProcessing(boolean enable) throws SQLException {
if (enable) {
throw new SQLException("Method not supported");
}
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setFetchDirection(int)
*/
@Override
public void setFetchDirection(int direction) throws SQLException {
checkConnection("setFetchDirection");
if (direction != ResultSet.FETCH_FORWARD) {
throw new SQLException("Not supported direction " + direction);
}
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setFetchSize(int)
*/
@Override
public void setFetchSize(int rows) throws SQLException {
checkConnection("setFetchSize");
fetchSize = rows;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setMaxFieldSize(int)
*/
@Override
public void setMaxFieldSize(int max) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setMaxRows(int)
*/
@Override
public void setMaxRows(int max) throws SQLException {
checkConnection("setMaxRows");
if (max < 0) {
throw new SQLException("max must be >= 0");
}
maxRows = max;
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setPoolable(boolean)
*/
@Override
public void setPoolable(boolean poolable) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Statement#setQueryTimeout(int)
*/
@Override
public void setQueryTimeout(int seconds) throws SQLException {
throw new SQLException("Method not supported");
}
/*
* (non-Javadoc)
*
* @see java.sql.Wrapper#isWrapperFor(java.lang.Class)
*/
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException {
return false;
}
/*
* (non-Javadoc)
*
* @see java.sql.Wrapper#unwrap(java.lang.Class)
*/
@Override
public <T> T unwrap(Class<T> iface) throws SQLException {
throw new SQLException("Cannot unwrap to " + iface);
}
/**
* Check whether query execution might be producing more logs to be fetched.
* This method is a public API for usage outside of Hive, although it is not part of the
* interface java.sql.Statement.
* @return true if query execution might be producing more logs. It does not indicate if last
* log lines have been fetched by getQueryLog.
*/
public boolean hasMoreLogs() {
return isLogBeingGenerated;
}
/**
* Get the execution logs of the given SQL statement.
* This method is a public API for usage outside of Hive, although it is not part of the
* interface java.sql.Statement.
* This method gets the incremental logs during SQL execution, and uses fetchSize holden by
* HiveStatement object.
* @return a list of logs. It can be empty if there are no new logs to be retrieved at that time.
* @throws SQLException
* @throws ClosedOrCancelledStatementException if statement has been cancelled or closed
*/
public List<String> getQueryLog() throws SQLException, ClosedOrCancelledStatementException {
return getQueryLog(true, fetchSize);
}
/**
* Get the execution logs of the given SQL statement.
* This method is a public API for usage outside of Hive, although it is not part of the
* interface java.sql.Statement.
* @param incremental indicate getting logs either incrementally or from the beginning,
* when it is true or false.
* @param fetchSize the number of lines to fetch
* @return a list of logs. It can be empty if there are no new logs to be retrieved at that time.
* @throws SQLException
* @throws ClosedOrCancelledStatementException if statement has been cancelled or closed
*/
public List<String> getQueryLog(boolean incremental, int fetchSize)
throws SQLException, ClosedOrCancelledStatementException {
checkConnection("getQueryLog");
if (isCancelled) {
throw new ClosedOrCancelledStatementException("Method getQueryLog() failed. The " +
"statement has been closed or cancelled.");
}
List<String> logs = new ArrayList<String>();
TFetchResultsResp tFetchResultsResp = null;
transportLock.lock();
try {
if (stmtHandle != null) {
TFetchResultsReq tFetchResultsReq = new TFetchResultsReq(stmtHandle,
getFetchOrientation(incremental), fetchSize);
tFetchResultsReq.setFetchType((short)1);
tFetchResultsResp = client.FetchResults(tFetchResultsReq);
Utils.verifySuccessWithInfo(tFetchResultsResp.getStatus());
} else {
if (isQueryClosed) {
throw new ClosedOrCancelledStatementException("Method getQueryLog() failed. The " +
"statement has been closed or cancelled.");
}
if (isExecuteStatementFailed) {
throw new SQLException("Method getQueryLog() failed. Because the stmtHandle in " +
"HiveStatement is null and the statement execution might fail.");
} else {
return logs;
}
}
} catch (SQLException e) {
throw e;
} catch (Exception e) {
throw new SQLException("Error when getting query log: " + e, e);
} finally {
transportLock.unlock();
}
RowSet rowSet = RowSetFactory.create(tFetchResultsResp.getResults(),
connection.getProtocol());
for (Object[] row : rowSet) {
logs.add(String.valueOf(row[0]));
}
return logs;
}
private TFetchOrientation getFetchOrientation(boolean incremental) {
if (incremental) {
return TFetchOrientation.FETCH_NEXT;
} else {
return TFetchOrientation.FETCH_FIRST;
}
}
}