| SQL Server database storage space is divided | | | | header. One of the possible causes is hardware |
| into pages, which are numbered sequentially. | | | | errors. The test that failed is defined in TEST |
| When you perform any operation, these pages | | | | string, while VAL1 and VAL2 are dependent upon |
| serve as the basic I/O unit. Each of these pages | | | | error state. |
| is marked with a corresponding header (96-byte | | | | Solution |
| in size) that conveys information like page | | | | To correct the above error, you need to follow |
| number, free space available, page type, object | | | | these steps:o You require examining system and |
| ID etc. | | | | application logs for hardware failures. Replace the |
| If you run DBCC CHECKDB on database and it | | | | affected hardware components. Also, you need |
| reports errors on database pages, the odds are | | | | to ensure that no write caching is enabled on disk |
| that the page header is damaged. This leads to | | | | controller (this is the issue when data corruption is |
| data inaccessibility and to restore lost information, | | | | observed frequently).o Use your recent data |
| you require using your recent data backup. | | | | backup to restore lost data.o In case of valid |
| However, if backup is damaged, not updated, or | | | | backup unavailability, run DBCC CHECKDB |
| not available, you need to use SQL recovery tools | | | | command to determine corruption state and |
| for safe repair and restoration. | | | | repair clause to be used. Next, you need to run |
| Consider a practical instance, you run DBCC | | | | DBCC CHECKDB with recommended repair clause. |
| CHECKDB on your SQL Server database and get | | | | Note: This process results into data loss as the |
| a series of error messages, similar to: | | | | affected pages will be deleted.o For safe SQL |
| Msg 8939, Level 16, State 98, Line 1. | | | | Repair, use commercial repair applications. SQL |
| Table error: Object ID O_ID, index ID I_ID, | | | | Recovery software are read-only, advanced, and |
| partition PA_ID, alloc unit ID AU_ID, page P_ID, | | | | automated software that scan damaged |
| Test (TEST) failed. Values are VAL1 and VAL2. | | | | databases and restore them with original content |
| Cause | | | | and view. |
| Error 8939 arises due to corruption in page | | | | |