[Oracle 恢复] 怎么样恢复ORA-600 [4194]---惜分飞

发布时间：2020-12-12 15:47:25 所属栏目：百科来源：网络整理

ERROR: Format: ORA-600 [4194] [a] [b]VERSIONS: versions 6.0 to 12.1 DESCRIPTION:A mismatch has been detected between Redo records and rollback (Undo) records.We are validating the Undo record number relating to the change being applied against the maximum undo record number recorded in the undo block.This error is reported when the validation fails.ARGUMENTS:Arg [a] Maximum Undo record number Undo blockArg [b] Undo record number from Redo block

ORA 600 4194 错误处理思路
第一步

Confirm whether the database is up and running or not. If the database fails to start or crashes shortly after startup due to this error occurring,then try setting event 10513 at level 2 the init.ora/spfileto disable transaction recovery and restart the instance,e.g.:event = "10513 trace name context forever,level 2"This may allow the database to successfully open and stay up so that the required diagnostics/actions can be performed.

第二步

In the trace file there should be an undo segment header dump,and so check to see if the undo segment header shows an active transaction after recovery,e.g.:TRN TBL <---- Represents the Transaction table for the particular undo segmentindex state cflags wrap# uel scn dba--------------------------------------------------------------------------------------------- 0x41 9 0x80 0x35ab6 0xffff 0x0695.38f6b959 0x1081e796 0x42 9 0x80 0x35bb1 0x000e 0x0695.38f6b028 0x1081e793 0x43 9 0x80 0x35b11 0x005d 0x0695.38f6b7ae 0x1081e795 0x44 9 0x80 0x359f0 0x0036 0x0695.38f69a91 0x1081e78e 0x45 10 0x80 0x35b1b 0x0000 0x0695.3a0aba4d 0x1081e796 0x46 9 0x80 0x35bb7 0x001c 0x0695.38f69bde 0x1081e78f ===================================State ---> This column specifies the status of the transaction 9 -----> represents a commited transaction10 ---> Represents a active transactionDba -----> Undo block containing the undo recordsStrictly speaking this is the block at the end of the undo chain.You can see from the transaction table that there is an active transaction this particular rollback/undo segment after recovery.Therefore this rollback segment and/or undo tablespace cannot be dropped without corrupting the database! Therefore recreating the UNDO tablespace is not an option.

第三步

From the trace determine the affected undo segment,e.g.:Block image after block recovery:UNDO BLK: xid: 0x0015.02b.0001544b seq: 0x163e cnt: 0x12 irb: 0x12 icl: 0x0 flg: 0x0000XID ==> Undo segment no + Slot no + Sequence no

Therefore,monospace!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; width:auto!important; direction:ltr!important; display:inline!important"> this

case the Undo Segment is:USN# 0x15 (Hex) ==> 21 (Dec) ==> _SYSSMU21$So and ONLY IF the transaction table shows no active transaction can therollback segment be offlined and dropped.Note however,that before you can confirm the entire UNDO tablespace can be dropped,you would need to check the transaction tables of ALL active rollback segments the same wasy as the above. The steps required to drop the rollback segment are fully detailed Note:179952.1,but are briefly listed here completeness:If using Automatic Undo ManagementOffline the undo segment using the _OFFLINE_ROLLBACK_SEGMENTS parameter and bounce the database as follows:1. Create and edit the init.ora file for the instance to set the following parameters:UNDO_MANAGEMENT=MANUAL _OFFLINE_ROLLBACK_SEGMENTS=(_SYSSMU21$)2. Open the database restricted mode to prevent user access,e.g.:connect / as sysdbastartup restrict pfile = '<Full path to init.ora file>';3. Drop the rollback segment,e.g.:drop rollback segment "_SYSSMU21";4. Shutdown the instance,and remove the init.ora parameters added point 1 and restart the instance,e.g.:shutdown immediatestartupIf SMON was recovering the transaction this may not work as we cannot the database it is determined to be an inconsistent state. I have reviewed a number of SRs where this approach was successful,so it is important to try it first but understand that it may fail and you will have to resort to a point in time recovery or forcing the DB and recreating it.

第四步

Now we need to dump the undo block to see which object was affected. We noted Step 2 that this is the active transaction (from the trace ): TRN TBL # uel scn dba 0x45 10 0x80 0x35b1b 0x0000 0x0695.3a0aba4d 0x1081e796 Dba----------------> Undo block containing the undo records dba--->0x1081e796 is the block containing the active transaction . Use the WebIV tools to convert this RDBA to block number (block#) and file number (file#),e.g.: V SPLIT ==> DBA (Hex) = File#,Block# (Hex File#,Block#) = ===== === ===== ============ V8 10,10 ==> 276948886 (0x1081e796) = 66,124822 (0x42 0x1e796) So the file# is 66 and the block# is 124822,so dump the block by issuing: SQL> Alter system dump datafile 66 block 124822; This will generate a trace in the user_dump_dest. The following is a sample of the information the undo block:UNDO BLK: xid: 0x000c.045.00035b1b : 0x1e14 cnt: 0x17 irb: 0x17 icl: 0x0 flg: 0x0000 Rec Offset Rec Offset Rec Offset Rec Offset Rec Offset --------------------------------------------------------------------------- 0x01 0x1f8c 0x02 0x1f30 0x03 0x1ed4 0x04 0x1e78 0x05 0x1e1c 0x06 0x1dc0 0x07 0x1d64 0x08 0x1d08 0x09 0x1cac 0x0a 0x1c50 0x0b 0x1bf4 0x0c 0x1b98 0x0d 0x1b3c 0x0e 0x1ae0 0x0f 0x1a74 0x10 0x1a18 0x11 0x19bc 0x12 0x1960 0x13 0x1904 0x14 0x187c 0x15 0x181c 0x16 0x1798 0x17 0x173c * Rec #0x16 slt: 0x45 objn: 1485619(0x0016ab33) objd: 1485619 tblspc: 71(0x00000047) * Layer: 11 (Row) opc: 1 rci 0x00 Undo type: Regular undo Begin trans Last buffer split: No Temp Object: No Tablespace Undo: No rdba: 0x00000000 *----------------------------- uba: 0x1081e796.1e14.14 ctl max scn: 0x0695.38f69853 prv tx scn: 0x0695.38f698a1 KDO undo record: KTB Redo op: 0x04 ver: 0x01 : L itl: scn: 0x0019.009.00034237 uba: 0x36c0cce4.1d2f.19 flg: C--- lkc: 0 scn: 0x0695.38f6b96b KDO Op code: URP xtype: XA bdba: 0x35406893 hdba: 0x35406892 itli: 1 ispac: 0 maxfr: 4863 tabn: 0 slot: 0(0x0) flag: 0x2c lock: 0 ckix: 0 ncol: 1 nnew: 1 size: -1 col 0: [ 4] c3 0e 36 2e *----------------------------- #0x17 slt: 0x45 objn: 1485619(0x0016ab33) objd: 1485619 tblspc: 71(0x00000047) * Layer: 11 (Row) opc: 1 rci 0x16 : Regular undo Last buffer : No Temp Object: No Tablespace Undo: No rdba: 0x00000000 *----------------------------- above:UNDO BLK: : 0x1e14 cnt: 0x17 irb: 0x17 icl: 0x0 flg: 0x0000The undo segment with the active transaction is segment is 0x000c (Hex) is 12 (Dec) as the XID is:Undo segment no + Slot no + Sequence noThis step is often skipped because it was performed earlier step 3,however it is a good idea to do this again now to make sure that the XID from the UNDO block matches the UNDO SEGMENT HEADER,this way you have followed all the chain,from the UNDO SEGMENT to UNDO BLOCK,back and forth. If there is a conflict here please check and sure that the customer dumped the correct undo block.Check the value of irb is an index points you to the latest change done to the undo block.This is the point from a rollback would begin one was issued. we see: 'irb: 0x17' so this points to record 0x17,so search this particular string i.e 0x17 and it will take you to undo record 'REC #0x17',e.g.:#0x17 slt: 0x45 objn: 1485619(0x0016ab33) objd: 1485619 tblspc: 71(0x00000047) * Layer: 11 (Row) opc: 1 rci 0x16 : No Temp Object: No Tablespace Undo: No rdba: 0x00000000 *----------------------------- Note the slot number (slt) is 0x45,the object number (objn) is the OBJECT_ID from dba_objects and data object number (objd) is the DATA_OBJECT_ID from dba_objects. These numbers may be the same but not necessarily,and so the database is open then identify this object,e.g.:select object_name,owner,object_type,data_object_id from dba_objects where object_id = <objn>;This is the object, has an active transaction. Note the above trace extract that rci has a value of 0x16 means that this record is at the end of an undo chain. This means that the chain continues another UNDO BLOCK. Please refer to unpublished Note:281504.1 information on Undo chains.So the next record that needs to be rolled back is present REC #X016. If rci is 0x00 it means that this is the first record present the undo chain and so you can check to see there is rdba info,e.g.:#0x16 slt: 0x45 objn: 1485619(0x0016ab33) objd: 1485619 tblspc: 71(0x00000047) * Layer: 11 (Row) opc: 1 rci 0x00 : No Temp Object: No Tablespace Undo: No rdba: 0x00000000 *----------------------------- uba: 0x1081e796.1e14.14 ctl max scn: 0x0695.38f69853 prv tx scn: 0x0695.38f698a1 KDO undo record: KTB Redo : 0x04 ver: 0x01 : L itl: scn: 0x0019.009.00034237 uba: 0x36c0cce4.1d2f.19 flg: C--- lkc: 0 scn: 0x0695.38f6b96b KDO Op code: URP xtype: XA bdba: 0x35406893 hdba: 0x35406892 itli: 1 ispac: 0 maxfr: 4863 tabn: 0 slot: 0(0x0) flag: 0x2c lock: 0 ckix: 0 ncol: 1 nnew: 1 size: -1 col 0: [ 4] c3 0e 36 2e *----------------------------- If the object is an Index,drop and recreate it. If it is a table, again the table would need to be dropped and recreated (or truncated) so that its object number changes and hence the rollback is no longer required.

If this isn't possible,monospace!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; width:auto!important; direction:ltr!important; display:inline!important"> you have two options:

First take a backup of the database its current state. This is critical in case anything goes wrong and you lose the opportunity to salvage the data! Option 1- Restore the undo segment datafile and the datafile containing the object and perform a full recovery.This can only be done if you have all the archived redo as you will need to full recovery on these files.OR Option 2If option 1 is not possible,you can use the unsupported method,e.g.:Specify the undo segment the _OFFLINE_ROLLBACK_SEGMENTS parameter and try to drop the rollback segment.If there is an active transaction this is not likely to work and you will probably need to the _CORRUPTED_ROLLBACK_SEGMENTS parameter as well

温馨提示： 1.隐含参数_OFFLINE_ROLLBACK_SEGMENTS/_CORRUPTED_ROLLBACK_SEGMENTS属于Oracle内部隐含参数,建议在Oracle support认可的情况下使用,因为使用之后可能导致数据库事务完整性彻底损坏 2.进行屏蔽事务之前,如果条件允许建议使用txchecker检查 2.使用上述方法恢复数据库之后，建议通过逻辑方式导出导入重建数据库

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标题：How to resolve ORA-600 [4194] errors

在oracle恢复中ORA-600 4194是一个非常常见的错误,该错误的主要原因是由于redo记录和undo(rollback)记录不匹配.
ORA 600 4194错误原因以及含义