Posted on Tuesday, April 27, 2010 at 11:06 PM
Pages in metadata structure of MS SQL Server database are either linked in a B-tree or heap tree format. These pages contain the records of different database components. In such situations, these pages instead of pointing the required pages, start pointing to a wrong page. The database records become inaccessible in case the SQL database gets corrupted or damaged. To access the records saved in the database components, an easy way is to restore the database objects from an updated backup. But, if in case the backup is not available, or backup file is not created, then you will need to repair the SQL database to access all its records. To do so, you will need to use advanced third-party SQL Recovery utility.
To briefly explain the above database corruption scenario, below is the error message that pops up when a SQL database table gets corrupted:
“Table error: Cross object linkage: Parent page P_ID1, slot S_ID1 in object ID O_ID1, index ID I_ID1, and page P_ID2, slot S_ID2 in object ID O_ID2, index ID I_ID2, next refer to page P_ID3 but are not in the same object.”...
Posted on Tuesday, April 27, 2010 at 2:25 AM
A table in MS SQL database can be corrupted due to various reasons. One of the most common being the corruption in metadata structure, caused due to damage of SQL Server damage. Once the table gets corrupted, it fails to display records stored in it. Furthermore, you also receive an "Table Error" message that does not allow you add any new records. An easy way to overcome such hazards is by restoring the table from an updated backup. But, with probabilities of backup file being corrupted, not updated, or inaccessible always exist. In such situations, the database user is left with no option, but to repair the corrupted table. To effectively do so, the user need to search for an advanced SQL Recovery application.
To illustrate the above case, below is a Table error message that appears after your SQL database table gets corrupted:
"Table error: Object ID O_ID, index ID I_ID, page P_ID. Test (TEST) failed. Slot S_ID, offset 0xADDRESS is invalid."...
Posted on Sunday, April 25, 2010 at 9:55 PM
Corruption of MS SQL database can result into damage of metadata structure entries, which can further result into inaccessibility of records saved in the SQL database components. In most cases of metadata structure damage, you receive an error message that specifies the exact metadata entry, which is corrupt. To overcome the error message and to access the database components records, an ideal way is to restore it from an updated backup. However, there are thousand of situations, where either the backup gets corrupted or the database administrator forgets to create a backup. In such cases, the only way to access records of a corrupted SQL database component is by repairing it with a powerful third-party MS Recover SQL application.
Consider a practical case, where you receive the below error message while trying to access a SQL database table:
“Table error: Object ID O_ID, index ID I_ID B-tree level mismatch, page P_ID1. Level LEVEL1 does not match level LEVEL2 from parent P_ID2.”...
Posted on Thursday, April 22, 2010 at 10:51 PM
A PFS (Page Free Space) page tracks the allocation status for every page and the amount of free space available on the page. The database engine uses the information stored in the PFS pages to allocate new pages. The page stores the information in the form of bytes, including a byte that indicates that the page is a mixed page. An IAM (Index Allocation Map) page, on the other hand is an array that stores all the mixed pages assigned to a particular index. The data stored in the database components becomes inaccessible if the page that is assigned a 'mixed page' byte in PFS page, not the same page does appear in the IAM page's array. This primarily occurs due to SQL database corruption. In such cases, the database becomes unmountable, further resulting into inaccessibility of its records. For complete accessibility of records in such situations, you will need to restore the data from an updated backup. But, if backup is not available, then you will need to use advanced MS SQL Recovery application...
Posted on Thursday, April 22, 2010 at 12:01 AM
The logical and physical integrity of all SQL Server database tables is performed by DBCC CHECKDB command. The command performs and divides its operations in three different phases. The first phase checks the consistency of the allocation structures in disk space, the second phase checks the integrity of all pages and their structures, and the last phase checks the catalog consistency. If critical errors are found in any of the phases, the DBCC CHECKDB command terminates immediately. This happens when the SQL Server database is badly corrupted, and is beyond the repairing capabilities of DBCC CHECKDB command. In such cases, if you need to access the database records, then you will need to restore the database records from a valid backup. But, if no backup is available or backup falls short to restore the required amount of data, then you will need to repair the database by using advanced MS SQL Server Recovery application...
Posted on Tuesday, April 20, 2010 at 9:06 PM
Corruption in MS SQL database is categorized into two forms – Logical and Physical. While the physical database corruption scenarios include damage of system components, the logical corruption situations only relate to software issues. The outcome for database corruption caused due to either of the two reasons in most cases is, unmountability of the database. An unmountable database does not allow you to access the records stored in the database. In such cases, an up-to-date backup (usually maintained by all the database users) allows you to restore the data and continue with your work. However, there have been thousands of case studies where either the user forgets to create an adequate backup or backup file itself gets corrupt. For such situations, the user needs to search for an effective MS Recover SQL application (for logical corruption) and database repair services (for physical crash scenarios).
Some of the most common logical corruption scenarios after which the database becomes unmountable are mentioned below:...
Posted on Monday, April 19, 2010 at 9:58 PM
An MS SQL Server database file is divided into various PFS (Page Free Space) intervals, approximately 64 MB in size. The byte-map of the PFS page consists of at least one byte per page for every page that is included in the PFS interval. The information stored in the PFS interval is very critical because corruption of it can result into database error, which stops you from accessing the records stored in the database. In such situations, the database corruption can be surmounted by restoring the data from an updated backup. However, the possibilities of database users forgetting to create an adequate backup, or the location where the backup is saved always exits. In such cases, the database user needs to opt for a powerful third-party SQL Server Recovery utility that can easily repair the database.
Picture a scenario, where you receive the underneath error message with your MS SQL Server database:
"Incorrect PFS free space information for page P_ID, object ID O_ID, index ID I_ID, in database ID DB_ID. Expected value PFS_VAL1, actual value PFS_VAL2."...
Posted on Friday, April 16, 2010 at 4:17 AM
PFS (Page Free Space) pages in SQL Server database not only maintains free spaces, but a lot more than that. Every SQL database file is divided into various PFS intervals, each containing 8088 pages. A PFS page contains a byte-map, which stores one byte for every page included in the PFS interval. Corruption in PFS page results into damage in the stored bytes, further resulting in making your database unmountable. The database records saved in the database become inaccessible after it becomes unmountable. For easy accessibility of records and to save your valuable time, you will need to restore the data from a valid backup. However, in case of backup unavailability or corruption, you will need to use a third-party MS SQL Database Recovery tool, which provides systematic repair.
As a practical example, you receive the below error message while mounting your SQL database:
"Database error: Page P_ID1 is marked with the wrong type in PFS page P_ID2. PFS status 0xVAL1 expected 0xVAL2."...
Posted on Wednesday, April 14, 2010 at 4:17 AM
Database corruption after unexpected system shutdown is a common scenario happened to almost all of us. The database becomes unmountable, further resulting in inaccessibility of records, after being corrupted. In most of these situations, you receive an error message that describes the exact cause of corruption, and sometimes its resolution too. However, if the resolution provided in the error message works, then there is no need to worry. But if in case, the resolution fails, then the best way to overcome database corruption is by restoring the data from an updated backup. Unavailability of a valid backup leaves you with no option, but to use advanced third-party SQL Database Recovery application to repair the database.
Consider a practical scenario, where your database unexpectedly stops and restarts again. On the restart, the database does not mount, and you view the below error messages in the error log file:...
Posted on Monday, April 12, 2010 at 9:00 PM
Restoration of data from an updated database backup allows you to overcome almost all SQL Server database corruption scenarios. It is therefore, always recommended to maintain a systematic database backup on some other storage media as well. While restoration of data is an easy process, it might result into an error message, which prevents you from restoration of the database. In such situations, an easy way is to restore the data from any other updated database backup. However if in case, no other backup is available or backup falls short to restore the data, then you will need to opt for advanced third-party SQL Database Recovery application.
Consider a practical scenario, where you encounter the underneath error message while restoration of data:
"Msg 8967, Level 16, State 216, Server <server name>, Line 2 An internal error occurred in DBCC which prevented further processing. Please contact Customer Support. DBCC results for '<database name>'. Msg 8921, Level 16, State 1, Server <server name>, Line 1 Check terminated. A failure was detected while collecting facts. Possibly tempdb out of space or a system table is inconsistent. Check previous errors."...