File: TxnEndTest.java

package info (click to toggle)
libdb-je-java 3.3.98-3
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 13,052 kB
  • sloc: java: 153,077; xml: 2,034; makefile: 3
file content (688 lines) | stat: -rw-r--r-- 21,988 bytes parent folder | download | duplicates (3)
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
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2002,2010 Oracle.  All rights reserved.
 *
 * $Id: TxnEndTest.java,v 1.74.2.2 2010/01/04 15:30:48 cwl Exp $
 */

package com.sleepycat.je.txn;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.Date;

import junit.framework.TestCase;

import com.sleepycat.je.Cursor;
import com.sleepycat.je.CursorConfig;
import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseConfig;
import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.DbInternal;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.je.EnvironmentStats;
import com.sleepycat.je.LockMode;
import com.sleepycat.je.OperationStatus;
import com.sleepycat.je.Transaction;
import com.sleepycat.je.TransactionStats;
import com.sleepycat.je.VerifyConfig;
import com.sleepycat.je.config.EnvironmentParams;
import com.sleepycat.je.dbi.DatabaseImpl;
import com.sleepycat.je.junit.JUnitThread;
import com.sleepycat.je.log.FileManager;
import com.sleepycat.je.util.TestUtils;

/*
 * Test transaction aborts and commits.
 */
public class TxnEndTest extends TestCase {
    private static final int NUM_DBS = 1;
    private Environment env;
    private File envHome;
    private Database[] dbs;
    private Cursor[] cursors;

    public TxnEndTest()
	throws DatabaseException {

        envHome = new File(System.getProperty(TestUtils.DEST_DIR));
    }

    public void setUp()
        throws IOException, DatabaseException {

        TestUtils.removeFiles("Setup", envHome, FileManager.JE_SUFFIX);

        /*
         * Run environment without in compressor on so we can check the
         * compressor queue in a deterministic way.
         */
        EnvironmentConfig envConfig = TestUtils.initEnvConfig();
        envConfig.setTransactional(true);
        envConfig.setConfigParam(EnvironmentParams.NODE_MAX.getName(), "6");
        envConfig.setConfigParam(EnvironmentParams.
				 ENV_RUN_INCOMPRESSOR.getName(),
                                 "false");
        envConfig.setAllowCreate(true);
        env = new Environment(envHome, envConfig);
    }

    public void tearDown()
        throws IOException, DatabaseException {

        if (env != null) {
            try {
                env.close();
            } catch (Exception e) {
                System.out.println("tearDown: " + e);
            }
        }
        env = null;

        TestUtils.removeFiles("TearDown", envHome, FileManager.JE_SUFFIX);
    }

    private void createDbs()
        throws DatabaseException {	

        // Make databases
        dbs = new Database[NUM_DBS];
        cursors = new Cursor[NUM_DBS];

        DatabaseConfig dbConfig = new DatabaseConfig();
        dbConfig.setTransactional(true);
        dbConfig.setAllowCreate(true);
        for (int i = 0; i < NUM_DBS; i++) {
            dbs[i] = env.openDatabase(null, "testDB" + i, dbConfig);
        }
    }

    private void closeAll()
        throws DatabaseException {	

        for (int i = 0; i < NUM_DBS; i++) {
            dbs[i].close();
        }
        dbs = null;
        env.close();
        env = null;
    }

    /**
     * Create cursors with this owning transaction
     */
    private void createCursors(Transaction txn)
        throws DatabaseException {

        for (int i = 0; i < cursors.length; i++) {
            cursors[i] = dbs[i].openCursor(txn, null);
        }
    }

    /**
     * Close the current set of cursors
     */
    private void closeCursors()
        throws DatabaseException {

        for (int i = 0; i < cursors.length; i++) {
            cursors[i].close();
        }
    }

    /**
     * Insert keys from i=start; i <end using a cursor
     */
    private void cursorInsertData(int start, int end)
        throws DatabaseException {

        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry data = new DatabaseEntry();
        for (int i = 0; i < NUM_DBS; i++) {
            for (int d = start; d < end; d++) {
                key.setData(TestUtils.getTestArray(d));
                data.setData(TestUtils.getTestArray(d));
                cursors[i].put(key, data);
            }
        }
    }
    /**
     * Insert keys from i=start; i < end using a db
     */
    private void dbInsertData(int start, int end, Transaction txn)
        throws DatabaseException {

        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry data = new DatabaseEntry();
        for (int i = 0; i < NUM_DBS; i++) {
            for (int d = start; d < end; d++) {
                key.setData(TestUtils.getTestArray(d));
                data.setData(TestUtils.getTestArray(d));
                dbs[i].put(txn, key, data);
            }
        }
    }

    /**
     * Modify keys from i=start; i <end
     */
    private void cursorModifyData(int start, int end, int valueOffset)
        throws DatabaseException {

        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry data = new DatabaseEntry();
        for (int i = 0; i < NUM_DBS; i++) {
            OperationStatus status =
		cursors[i].getFirst(key, data, LockMode.DEFAULT);
            for (int d = start; d < end; d++) {
                assertEquals(OperationStatus.SUCCESS, status);
                byte[] changedVal =
                    TestUtils.getTestArray(d + valueOffset);
                data.setData(changedVal);
                cursors[i].putCurrent(data);
                status = cursors[i].getNext(key, data, LockMode.DEFAULT);
            }
        }
    }

    /**
     * Delete records from i = start; i < end.
     */
    private void cursorDeleteData(int start, int end)
        throws DatabaseException {

        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry foundData = new DatabaseEntry();
        for (int i = 0; i < NUM_DBS; i++) {
            for (int d = start; d < end; d++) {
                byte[] searchValue =
                    TestUtils.getTestArray(d);
                key.setData(searchValue);
                OperationStatus status =
		    cursors[i].getSearchKey(key, foundData, LockMode.DEFAULT);
                assertEquals(OperationStatus.SUCCESS, status);
                assertEquals(OperationStatus.SUCCESS, cursors[i].delete());
            }
        }
    }

    /**
     * Delete records with a db.
     */
    private void dbDeleteData(int start, int end, Transaction txn)
        throws DatabaseException {

        DatabaseEntry key = new DatabaseEntry();
        for (int i = 0; i < NUM_DBS; i++) {
            for (int d = start; d < end; d++) {
                byte[] searchValue =
                    TestUtils.getTestArray(d);
                key.setData(searchValue);
                dbs[i].delete(txn, key);
            }
        }
    }

    /**
     * Check that there are numKeys records in each db, and their value
     * is i + offset.
     */
    private void verifyData(int numKeys, int valueOffset)
        throws DatabaseException {

        for (int i = 0; i < NUM_DBS; i++) {
            /* Run verify */
            DatabaseImpl dbImpl = DbInternal.dbGetDatabaseImpl(dbs[i]);
            assertTrue(dbImpl.verify(new VerifyConfig(),
                                      dbImpl.getEmptyStats()));

            Cursor verifyCursor =
		dbs[i].openCursor(null, CursorConfig.READ_UNCOMMITTED);
            DatabaseEntry key = new DatabaseEntry();
            DatabaseEntry data = new DatabaseEntry();
            OperationStatus status =
		verifyCursor.getFirst(key, data, LockMode.DEFAULT);
            for (int d = 0; d < numKeys; d++) {
                assertEquals("key=" + d, OperationStatus.SUCCESS, status);
                byte[] expected = TestUtils.getTestArray(d + valueOffset);
                assertTrue(Arrays.equals(expected, key.getData()));
                assertTrue("Expected= " + TestUtils.dumpByteArray(expected) +
                           " saw=" + TestUtils.dumpByteArray(data.getData()),
                           Arrays.equals(expected, data.getData()));
                status = verifyCursor.getNext(key, data, LockMode.DEFAULT);
            }
            // should be the end of this database
            assertTrue("More data than expected",
		       (status != OperationStatus.SUCCESS));
            verifyCursor.close();
        }
    }

    /**
     * Test basic commits, aborts with cursors
     */
    public void testBasicCursor()
        throws Throwable {

        try {
            int numKeys = 7;
            createDbs();

            // Insert more data with a user transaction, commit
            Transaction txn = env.beginTransaction(null, null);
            createCursors(txn);
            cursorInsertData(0, numKeys*2);
            closeCursors();
            txn.commit();
            verifyData(numKeys*2, 0);

            // Insert more data, abort, check that data is unchanged
            txn = env.beginTransaction(null, null);
            createCursors(txn);
            cursorInsertData(numKeys*2, numKeys*3);
            closeCursors();
            txn.abort();
            verifyData(numKeys*2, 0);

            /*
             * Check the in compressor queue, we should have some number of
             * bins on. If the queue size is 0, then check the processed stats,
             * the in compressor thread may have already woken up and dealt
             * with the entries.
             */
            EnvironmentStats envStat = env.getStats(TestUtils.FAST_STATS);
            long queueSize = envStat.getInCompQueueSize();
            assertTrue(queueSize > 0);

            // Modify data, abort, check that data is unchanged
            txn = env.beginTransaction(null, null);
            createCursors(txn);
            cursorModifyData(0, numKeys * 2, 1);
            closeCursors();
            txn.abort();
            verifyData(numKeys*2, 0);

            // Delete data, abort, check that data is still there
            txn = env.beginTransaction(null, null);
            createCursors(txn);
            cursorDeleteData(numKeys+1, numKeys*2);
            closeCursors();
            txn.abort();
            verifyData(numKeys*2, 0);
            // Check the in compressor queue, nothing should be loaded
            envStat = env.getStats(TestUtils.FAST_STATS);
            assertEquals(queueSize, envStat.getInCompQueueSize());

            // Delete data, commit, check that data is gone
            txn = env.beginTransaction(null, null);
            createCursors(txn);
            cursorDeleteData(numKeys, numKeys*2);
            closeCursors();
            txn.commit();
            verifyData(numKeys, 0);

            // Check the inCompressor queue, there should be more entries.
            envStat = env.getStats(TestUtils.FAST_STATS);
            assertTrue(envStat.getInCompQueueSize() > queueSize);

            closeAll();

        } catch (Throwable t) {
            // print stacktrace before attempt to run tearDown
            t.printStackTrace();
            throw t;
        }
    }

    /**
     * Test db creation and deletion.
     */
    public void testTxnClose()
        throws DatabaseException {

        createDbs();
        Transaction txn = env.beginTransaction(null, null);
        createCursors(txn);
        try {
            txn.commit();
            fail("Commit should fail");
        } catch (DatabaseException e) {
        }
	closeCursors();
        closeAll();
    }

    class CascadingAbortTestJUnitThread extends JUnitThread {
	Transaction txn = null;
	Database db = null;

	CascadingAbortTestJUnitThread(Transaction txn,
				      Database db) {
	    super("testCascadingAborts");
	    this.txn = txn;
	    this.db = db;
	}
    }

    /**
     * Test cascading aborts in the face of deletes.
     * [work in progress: cwl 1/15/04]
     */
    public void xtestCascadingAborts()
	throws Throwable {

        Database db = null;

	try {
	    DatabaseConfig dbConfig = new DatabaseConfig();
	    dbConfig.setAllowCreate(true);
            dbConfig.setTransactional(true);
	    db = env.openDatabase(null, "testDB", dbConfig);

	    DatabaseEntry key = new DatabaseEntry();
	    DatabaseEntry data = new DatabaseEntry();

	    Transaction txn = env.beginTransaction(null, null);
	    key.setData("abb".getBytes());
	    data.setData("def".getBytes());
	    //db.put(txn, key, data, null);
	    key.setData("abc".getBytes());
	    data.setData("def".getBytes());
	    db.put(txn, key, data);
	    txn.commit();

	    //DbInternal.dbGetDatabaseImpl(db).getTree().dump();

	    Transaction txn1 = env.beginTransaction(null, null);
	    Transaction txn2 = env.beginTransaction(null, null);

	    CascadingAbortTestJUnitThread tester1 =
		new CascadingAbortTestJUnitThread(txn2, db) {
		    public void testBody()
			throws Throwable {

			Cursor c = db.openCursor(txn, null);
			DatabaseEntry data = new DatabaseEntry();
			try {
			    Thread.yield();
			    DatabaseEntry key = new DatabaseEntry();
			    key.setData("abc".getBytes());
			    OperationStatus status =
				c.getSearchKeyRange(key, data, LockMode.DEFAULT);
			    assertEquals(status, OperationStatus.SUCCESS);
			    status = c.delete();
			    assertEquals(status, OperationStatus.SUCCESS);
			} catch (Throwable T) {
			    T.printStackTrace();
			} finally {
			    c.close();
			}
		    }
		};

	    tester1.start();
	    Thread.yield();
	    key.setData("abc".getBytes());
	    OperationStatus status = db.delete(txn1, key);
	    assertEquals(OperationStatus.SUCCESS, status);

	    txn1.abort();
	    Thread.yield();

	    txn2.abort();
	    tester1.finishTest();

	    //DbInternal.dbGetDatabaseImpl(db).getTree().dump();

	    if (false) {
		db.close();
		env.close();
		EnvironmentConfig envConfig = TestUtils.initEnvConfig();
		envConfig.setTransactional(true);
		envConfig.setConfigParam(EnvironmentParams.NODE_MAX.getName(),
					 "6");
		envConfig.setConfigParam(EnvironmentParams.
					 ENV_RUN_INCOMPRESSOR.
					 getName(),
					 "false");
		envConfig.setAllowCreate(true);
		env = new Environment(envHome, envConfig);
		db = env.openDatabase(null, "testDB", dbConfig);
	    }

	    txn = env.beginTransaction(null, null);
	    System.out.println(db.getSearchBoth(txn, key, data,
                                                LockMode.DEFAULT));
	    txn.commit();
	} catch (Throwable T) {
	    T.printStackTrace();
	} finally {
	    db.close();
	}
    }

    /**
     * Test use through db.
     */
    public void testBasicDb()
        throws Throwable {

        try {
            TransactionStats stats =
                env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(0, stats.getNAborts());
            int initialCommits = 1; // 1 commits for adding UP database
            assertEquals(initialCommits, stats.getNCommits());

	    long locale = new Date().getTime();
	    TransactionStats.Active[] at = new TransactionStats.Active[4];
	
	    for(int i = 0; i < 4; i++) {
                at[i] = new TransactionStats.Active("TransactionStatForTest",
			                     	    i, i - 1);
	    }

	    stats.setActiveTxns(at);
	    stats.setLastCheckpointTime(locale);
	    stats.setLastTxnId(3);
	    stats.setNAborts(12);
	    stats.setNXAAborts(15);
	    stats.setNActive(20);
	    stats.setNBegins(25);
	    stats.setNCommits(1);
	    stats.setNXACommits(30);
	    stats.setNXAPrepares(20);

	    TransactionStats.Active[] at1 = stats.getActiveTxns();
	
	    for(int i = 0; i < 4; i++) {
		assertEquals("TransactionStatForTest", at1[i].getName());
		assertEquals(i, at1[i].getId());
		assertEquals(i - 1, at1[i].getParentId());
		at1[i].toString();
	    }
	    assertEquals(locale, stats.getLastCheckpointTime());
	    assertEquals(3, stats.getLastTxnId());
	    assertEquals(12, stats.getNAborts());
	    assertEquals(15, stats.getNXAAborts());
	    assertEquals(20, stats.getNActive());
	    assertEquals(25, stats.getNBegins());
	    assertEquals(1, stats.getNCommits());
	    assertEquals(30, stats.getNXACommits());
	    assertEquals(20, stats.getNXAPrepares());
	    stats.toString();
	
	    stats.setActiveTxns(null);
	    stats.toString();

            int numKeys = 7;
            createDbs();

            // Insert data with autocommit
            dbInsertData(0, numKeys, null);
            verifyData(numKeys, 0);

            // Insert data with a txn
            Transaction txn = env.beginTransaction(null, null);
            dbInsertData(numKeys, numKeys*2, txn);
            txn.commit();
            verifyData(numKeys*2, 0);

            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(0, stats.getNAborts());
            assertEquals((initialCommits + 1 +  // 1 explicit commit above
                          (1 * NUM_DBS) +       // 1 per create/open
                          (numKeys*NUM_DBS)),   // 1 per record, using autotxn
			 stats.getNCommits());

            // delete data with a txn, abort
            txn = env.beginTransaction(null, null);
            dbDeleteData(numKeys, numKeys * 2, txn);
            verifyData(numKeys, 0);  // verify w/dirty read
            txn.abort();

            closeAll();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }
    /**
     * Test TransactionStats.
     */
    public void testTxnStats()
        throws Throwable {

        try {
            TransactionStats stats =
                env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(0, stats.getNAborts());
            int numBegins = 1; // 1 begins for adding UP database
            int numCommits = 1; // 1 commits for adding UP database
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());

            int numKeys = 7;
            createDbs();
            numBegins += NUM_DBS; // 1 begins per database
            numCommits += NUM_DBS; // 1 commits per database
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());

            /* Insert data with autocommit. */
            dbInsertData(0, numKeys, null);
            numBegins += (numKeys * NUM_DBS);
            numCommits += (numKeys * NUM_DBS);
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());
            verifyData(numKeys, 0);

            /* Insert data with a txn. */
            Transaction txn = env.beginTransaction(null, null);
            numBegins++;
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());
            assertEquals(1, stats.getNActive());
            dbInsertData(numKeys, numKeys*2, txn);
            txn.commit();
            numCommits++;
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());
            assertEquals(0, stats.getNActive());
            verifyData(numKeys*2, 0);

            /* Delete data with a txn, abort. */
            txn = env.beginTransaction(null, null);
            numBegins++;
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());
            assertEquals(1, stats.getNActive());

            dbDeleteData(numKeys, numKeys * 2, txn);
            verifyData(numKeys, 0);  // verify w/dirty read
            txn.abort();
            stats = env.getTransactionStats(TestUtils.FAST_STATS);
            assertEquals(numBegins, stats.getNBegins());
            assertEquals(numCommits, stats.getNCommits());
            assertEquals(1, stats.getNAborts());
            assertEquals(0, stats.getNActive());

            closeAll();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    /**
     * Test db creation and deletion
     */

    public void testDbCreation()
        throws DatabaseException {

        Transaction txnA = env.beginTransaction(null, null);
        Transaction txnB = env.beginTransaction(null, null);

        DatabaseConfig dbConfig = new DatabaseConfig();
        dbConfig.setAllowCreate(true);
        dbConfig.setTransactional(true);
        Database dbA =
	    env.openDatabase(txnA, "foo", dbConfig);

        // Try to see this database with another txn -- we should not see it

        dbConfig.setAllowCreate(false);

        try {
            txnB.setLockTimeout(1000);

		env.openDatabase(txnB, "foo", dbConfig);
            fail("Shouldn't be able to open foo");
        } catch (DatabaseException e) {
        }
	/* txnB must be aborted since openDatabase timed out. */
	txnB.abort();

        // Open this database with the same txn and another handle
        Database dbC =
	    env.openDatabase(txnA, "foo", dbConfig);

        // Now commit txnA and txnB should be able to open this.
        txnA.commit();
	txnB = env.beginTransaction(null, null);
        Database dbB =
	    env.openDatabase(txnB, "foo", dbConfig);
        txnB.commit();

        // XXX, test db deletion

        dbA.close();
        dbB.close();
        dbC.close();
    }

    /* Test that the transaction is unsable about a close. */
    public void testClose()
        throws DatabaseException {

        Transaction txnA = env.beginTransaction(null, null);
        txnA.commit();

        try {
            env.openDatabase(txnA, "foo", null);
            fail("Should not be able to use a closed exception");
        } catch (DatabaseException expected) {
        }
    }

}