No existing server environment is error free and so is the case with MS SQL Server. In addition to many others the two familiar associated errors are SQL Server error 644 and 8646. Moreover, it mostly occurs in SQL Server version 2000 and above. The complete message of the two error codes appear as follows in the Server’s error log.
"Error: 644, Severity: 21, State: 5
Could not find the index entry for RID ‘1613b1000000100’ in index page (1:189), index ID 7, database ‘TestDB’.
Error: 8646, severity: 21, State: 1
The index entry for row ID was not found in index ID 7, of table 2009058193, in database ‘test644’."
Cause - The two errors may occur and hinder the proper functioning of the Server, at the time of Delete or Update actions performed against or within a Table, which stores a Unicode Column with a Latin1_General_BIN Collation.
Explanation - From the above displayed entire error message it is clear that error with code number 644 has the severity of 21 and its state is 5. While the error with code number 8646 has severity levels same as error 644 i.e. 21 but state 1. Regardless of the severity level of the errors prompted against certain operations, the conclusion is that the errors affect the SQL Server database MDF and related NDF file making the stored important data items unattainable.
Usually, it is suggested to make use of DBCC CHECKDB statement to fix errors of SQL Server. But the type of index corruption mentioned here, that occurs on updating or deleting data in table shall not report any errors either related to integrity or consistency of the Server database, on executing DBCC CHECKDB. The utility shall report errors only after the exact fix related to the error 644 and 8646 is applied. Therefore, it is not useful to run the integrity and consistency check utility beforehand. But it is advised to get rid of the error with the hotfix that has been particularly devised for it by the developer of SQL Server i.e. Microsoft. The error reported might be as given shown below or similar to it.
Sever: Msg 2511, Level 16, state 1, Line 1
Table error: Object ID 2009058193, Index ID 7. Keys out of order on page (1:189), slots 184 and 185."
Note - The above mentioned example of the SQL error message is specifically associated with non-clustered index of the Server. Nonetheless, it can occur with the clustered indexes as well.
Hotfix to Fix Error Code 644 & 8646 – SQL error 644 and 8646 are specifically related to SQL Server edition 2000 and is common one that occurs usually. Moreover, it is quite an old version that was introduced years back. Therefore, Microsoft has come up with SQL Server 2000 fixes that are available as single downloadable file now. Moreover, as the fixes are growing day by day, each new release contains all hotfix as well as all the security fixes including the ones that were present in older releases of SQL Server 2000 fix.
How to Get Rid of Above Discussed Error?
After the devised hotfix is applied and DBCC CHECKDB utility executed, if the Server returns any index corruption related error message as mentioned above, users must rebuild the index on the table that appears in the error message. This must be done so as to fix the error and remove corruption issue. However, if the manual process fails to eradicate the SQL database MDF file damage and resulting errors completely, usage of any external application must be made.
There is no doubt that Microsoft, the manufacturer of the talked about RDBMS server here, has come up with well developed tool so as to fix all sorts of errors related to SQL server 2000 including SQL error 644 and 8646. But at times the devised procedure fails to work and comes up with damaged primary and secondary database file. In such cases when the resultant output is too a corrupt file, the one application that can certainly come to assistance is third party tool.
It is such a software application that has the ability to fix SQL Server database corruption issues that might affect the primary MDF file and its associated NDF file. It guarantees recovery from all types of errors irrespective of the severity and state level. Moreover, it ensures recovery from Tables, Triggers, Functions, Rules, Stored Procedures, etc. recovery without data loss. The software also supports recovery of permanently deleted data items from Table. Indeed, it must be mentioned that the suggested third party utility is an apt tool that is composed of many super features and high rated functionalities.