很难说它是如何发生的。我使用mongodb作为hadoop输出（com.mongodb.hadoop）。一开始似乎没事。当我试图对数据进行修改时，这个问题刚刚爆发。我无法从umongo（https://github.com/agirbal/umongo）和＆amp ;;中读取输出集合数据。 mongoHub（http://mongohub.todayclose.com/）。我甚至无法通过回滚我的代码来解决它。
以下是来自umongo的追踪
java.lang.UnsupportedOperationException: BSONDecoder doesn't understand type : 53 name: S
at org.bson.BasicBSONDecoder.decodeElement(BasicBSONDecoder.java:226)
at org.bson.BasicBSONDecoder.decodeElement(BasicBSONDecoder.java:206)
at org.bson.BasicBSONDecoder._decode(BasicBSONDecoder.java:79)
at org.bson.BasicBSONDecoder.decode(BasicBSONDecoder.java:57)
at com.mongodb.DefaultDBDecoder.decode(DefaultDBDecoder.java:56)
at com.mongodb.Response.<init>(Response.java:66)
at com.mongodb.DBPort.go(DBPort.java:128)
at com.mongodb.DBPort.call(DBPort.java:79)
at com.mongodb.DBTCPConnector.call(DBTCPConnector.java:218)
at com.mongodb.DBApiLayer$MyCollection.__find(DBApiLayer.java:305)
at com.mongodb.DBCursor._check(DBCursor.java:369)
at com.mongodb.DBCursor.getServerAddress(DBCursor.java:687)
at com.mongodb.DBCursor.toString(DBCursor.java:740)
at com.edgytech.umongo.CollectionPanel$4.getRoot(CollectionPanel.java:427)
at com.edgytech.umongo.DbJob.wrapUp(DbJob.java:130)
at com.edgytech.umongo.DbJob$1.done(DbJob.java:81)
at javax.swing.SwingWorker$5.run(SwingWorker.java:717)
at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.run(SwingWorker.java:814)
at sun.swing.AccumulativeRunnable.run(AccumulativeRunnable.java:95)
at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.actionPerformed(SwingWorker.java:824)
at javax.swing.Timer.fireActionPerformed(Timer.java:291)
at javax.swing.Timer$DoPostEvent.run(Timer.java:221)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:682)
at java.awt.EventQueue.access$000(EventQueue.java:85)
at java.awt.EventQueue$1.run(EventQueue.java:643)
at java.awt.EventQueue$1.run(EventQueue.java:641)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:652)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
MongoDB：来自HomeBrew的mongodb-2.2.0-x86_64（http://mxcl.github.com/homebrew/）
操作系统：Mac OS 10.8.1
司机：2.7.2＆amp; 2.7.3
更新
来自mongo shell的错误
Wed Sep 26 09:24:20 Assertion: 10320:BSONElement: bad type 53
0x10004656b 0x1000b9b1e 0x100013a62 0x100292425 0x10011ef2e 0x100120ec8 0x10014ab74 0x1001498f4 0x1001cd414 0x1001490fc 0x10014ad81 0x100159c8f 0x100255418 0x10025551b 0x10029d0ba 0x100007277 0x10000919a 0x100000dd4 0x1
0 mongo 0x000000010004656b _ZN5mongo15printStackTraceERSo + 43
1 mongo 0x00000001000b9b1e _ZN5mongo11msgassertedEiPKc + 206
2 mongo 0x0000000100013a62 _ZNK5mongo11BSONElement4sizeEv + 418
3 mongo 0x0000000100292425 _ZN5mongo16resolveBSONFieldEP9JSContextP8JSObjectljPS3_ + 389
4 mongo 0x000000010011ef2e js_LookupPropertyWithFlags + 734
5 mongo 0x0000000100120ec8 js_GetProperty + 136
6 mongo 0x000000010014ab74 js_Interpret + 3396
7 mongo 0x00000001001498f4 js_Invoke + 3300
8 mongo 0x00000001001cd414 fun_apply + 532
9 mongo 0x00000001001490fc js_Invoke + 1260
10 mongo 0x000000010014ad81 js_Interpret + 3921
11 mongo 0x0000000100159c8f js_Execute + 1103
12 mongo 0x0000000100255418 JS_EvaluateUCScriptForPrincipals + 168
13 mongo 0x000000010025551b JS_EvaluateScript + 107
14 mongo 0x000000010029d0ba _ZN5mongo7SMScope4execERKNS_10StringDataERKSsbbbi + 330
15 mongo 0x0000000100007277 _Z5_mainiPPc + 12599
16 mongo 0x000000010000919a main + 42
17 mongo 0x0000000100000dd4 start + 52
18 ??? 0x0000000000000001 0x0 + 1
Error: BSONElement: bad type 53