One type of database corruption that is reported to Technical Support is typically associated with Assertion Error 50213, "Page number on page does not match page requested". When running on an ASA 6 or 7, the assertion will likely be 200601, "Page for requested record not a table page or record not present on page." Most frequently, however, said database was created on version 5.x and became corrupted before upgrading the software. Occasionally other assertions are reported, depending on the operation that first fails.
Our Product Quality department has stated that they would prefer to receive all databases in-house that become corrupted on version of the software that is currently being developed (as of this writing, SSA 5.5.05, ASA 6.0.4, ASA 7.0.1) in order to investigate the causes and frequency of database corruption. In some cases, however, the procedure described below can be more expedient. Furthermore, if the you are running on software that is no longer being updated (typically the maintenance level currently being sold plus one level earlier), the usefulness of such information is limited.
In all cases of database corruption, the preferred resolution is to find a valid backup, and apply all of the log files since the time of the backup.
This type of corruption is particularly bothersome, however, because it only manifests itself when a particular database page is accessed. If the data on that page is rarely used, the corruption may well exist on many or all of the backups the customer has on hand.
It may be possible to recover the database with the following procedure, although it is likely that some data will be lost. It is up to the customer to determine the validity and completeness of the data in the recovered database.
You will want to use the dbunload command; therefore it is prudent to note the following dbunload switches:
(at the command prompt type: dbunload /? )
Usage: dbunload [switches] <directory> [table-name-list]
Switches (use specified lower-case letter, as shown):
- -c "keyword=value; ..."
supply database connection parameters
-d unload data only
-e no data output for listed tables
-g <user> specify user name as replacement for dbo
-ii internal unload, internal reload (default)
-ix internal unload, external reload
-j <count> iteration count for view creation statements
-n no data - schema definition only
-o <file> log output messages to file
-p <char> escape character (default "\")
-q quiet: do not print messages or show windows
-r <file> specify name of generated reload ISQL
command file (default "reload.sql")
-u unordered data
-v verbose messages
-xi external unload, internal reload
-xx external unload, external reload
-y overwrite command file without confirmation
