Monday, August 17, 2009

Resolving SQL Page with Incorrect Type Error

All the SQL database files are split into PFS intervals, where PFS stands for Page Free Space. A PFS interval is about 64 MB in size and has 8088 pages in it. Each PFS page has a byte-map with one byte per page for all the pages included in the PFS interval. At times, you get database errors that indicate that a page exists with invalid type in its PFS page. Database corrupted in this way needs to be restored from backup. However, if you don't have any valid data backup available, you need to use advanced SQL Recovery application.

For an instance, you might come across the similar error message with your SQL Server database:

“Database error: Page P_ID1 is marked with the wrong type in PFS page P_ID2. PFS status 0xVAL1 expected 0xVAL2.”

This error is marked as error 8948 in SQL Server error log.

Cause

The above error results when a page P_ID1 has been marked with incorrect type entry in PFS page P_ID2. As described above, each PFS page has a byte-map with one byte per page for all the pages included in the PFS interval. Among rest of the information, each byte contains three specific type of status bits that define the page type:

(0x10) for PFS_IS_IAM_PG
(0x40) for PFS_IS_ALLOCATED
(0x20)for PFS_IS_MIXED_EXT

Error 8948 occurs when these bits are improperly set.

Solution

You need to deploy these measures to cope up with such issues:

If such kind of problems are persistent in nature, you should check the system for possible hardware problems first. You can do so by examining the error log reports of Windows, SQL Server™ and application.
Check the database backup status. If complete and valid, delete the damaged database and restore from the backup.
Without using any repair clause, execute DBCC CHECKDB to determine the required repair clause to be applied. Next, run DBCC CHECKDB with this repair clause.
If you desire to prevent data loss that might occur due to the above step, you need to use advanced SQL Repair tools. These are safe SQL Recovery software that can scan a corrupted database and restore it successfully.

Stellar Phoenix SQL Recovery is a premier tool to repair damaged SQL databases and is supportive to SQL Server 2008, 2005 and 2000. With self-descriptive and exceptionally realistic interface, advanced repair options and non-destructive design, it is an effective SQL Repair tool to repair all database objects. The software is compatible with Windows Vista, XP, 2003, 2000 and NT.

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