Oracle Database cannot be opened

Oracle databases cannot be opened due to the following reasons: improper parameter settings control file damage log file damage data file header damage data dictionary damage UNDO damage SMON rollback transaction problems if you are not sure about the problem, you can find the shita software professional ORACLE Database repair team to help you recovery! Shita software professional database repair

Oracle databases cannot be opened due to the following reasons: improper parameter settings control file damage log file damage data file header damage data dictionary damage UNDO damage SMON rollback transaction problems if you are not sure about the problem, you can find the shita software professional ORACLE Database repair team to help you recovery! Shita software professional database repair

Oracle databases cannot be opened due to the following reasons:

• Incorrect Parameter settings
• Control File Corruption
• Log File Corruption
• Damaged Data File Header
• Data Dictionary corruption
• UNDO corruption
• SMON encountered problems during transaction rollback

If you are not sure, contact the professional ORACLE Database repair team of shita software to help you recover it! Shita software professional database repair team Service Hotline: 400-690-3643? ? Backup phone: 18501767907? ? Email: service@parnassusdata.com

For different errors such as ORA-00600/ORA-07445, there can be different ways to deal:

In ORACLE, there are various diagnostic procedures for corruption/damage of data blocks, but the symptoms are roughly as follows:

• ORA-01578 error.
• ORA-600 [61xx] Error
• ORA-600 [3339] Or ORA-600 [3398]
• ORA-600 [2130], ORA-600 [2845], ORA-600 [4147] errors and so on
• The SELECT statement queries incorrect data.

The following three steps should be taken to diagnose the problem of ORACLE data block corruption/Bad Block:

1. If the database is still open, you need to determine the data file number and block number of the damaged/damaged block and locate the specific object (which may be a table or index ). Combined with the ORA-1578 error or the variable information reported by the ORA-600, take the following SQL to locate

SELECT tablespace_name, segment_type, owner, segment_nameFROM dba_extentsWHERE file_id = &fileidand &blockid between block_id AND block_id + blocks - 1;

2. Depending on the SEGMENT_TYPE obtained in the previous step, the following SEGMENT_TYPE can be rebuilt:

• Index
• Tables that can be retrieved again or that can be rebuilt
• Rollback segment, except for the SYSTEM rollback segment
• Sorting segment, sort segment
• Temporary table

3. If it does not belong to any of the expenditures in step 2, pay attention to the following information:

• Whether the database is in archive Mode
• Whether there is any table backup data, including export/sqlldr
• Is there an index based on the not null field on the table?
• If such an index exists, is it UNIUQE?

4. Is there a block damage/Bad block in this database? Experienced DBAs can get a general understanding of the situation from alert. log. If such problems have occurred in the past, you can refer to the subsequent suggestions below.

5. If you are using the archive mode, it is recommended that you save an archive redo and online log for future diagnosis. If not, the user is required to back up all online logs.

6. If conditions are met, perform 10212, and events to capture the error source. If the on-site engineers suspect that the problem is not caused by ORACLE, we recommend that you dump the problematic data block and analyze it with the OS, storage, and volume manager logs .? If it is suspected that the memory is damaged, it is necessary to consider _ db_block_cache_protect. Note that not all platforms support _ db_block_cache_protect and the performance is much damaged.

7. In some cases, it is necessary for users to enable the archive mode to avoid the failure to effectively recover from subsequent problems

Evidence to be collected

1. Including the oracle trace and ALERT files, which are the source for diagnosing such problems and analyzing whether other data blocks in these reports are reported to be damaged.

2. Dump bad data blocks from the OS perspective

Unix: dd if = badfile. dbf count = 5 bs = 2048 skip = 75

Follow-up suggestions

1. When analyzing the trace or redo log dump, it is necessary to adjust the user's expectations and express the information to the user:

• We are helping to identify the cause rather than how to fix these bad blocks.
• We are studying this evidence, but it may not make a decisive conclusion.

2. Sometimes data blocks are corrupted in memory, such as ORA-600 [3398], to verify that these situations can:

• Analyze table X validate structure cascade;
• Alter system flush buffer_cache;
• Dump and analyze the data block from the OS perspective

Follow-up measures

1. Search for the essence, such:

• All damages occur only on a bare device, device, or controller.
• One bad block appears for each four blocks.
• The data block itself is okay, but the location is incorrect.
• The part of the data block is healthy, but the rest is incorrect.

2. Rebuild the table by bypassing the damaged/broken block data blocks:

Use the 10231 level 10 event to execute a full table scan CTAS

Build ROWID to avoid access to corrupted data blocks [data recovery] using the construction of ROWID to achieve no backup without bypassing ORA-1578, ORA-8103, ORA-1410 and other logical/Physical Bad block problems

3. Enable 10210, 10211, and 10212, and update the data block to further locate the details of the Bad block, and consider using the 10231 event

Other tools

Other optional tools include dul, oranum, orapatch, and bbed, which are all internal ORACLE tools.

Related posts:

1. [Oracle data recovery] data block damage/Bad Block Diagnosis
2. Use RMAN to detect bad database block scripts

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