Sybase 12.4.2 User Manual

CHAPTER 11    Backup and Data Recovery

Ensuring that all files 
exist

Before restoring, review the table of contents of the backup to ensure that all 
files required for IQ are present. The list of files depends on your application. 
See the discussion of required and optional files in “Backing up the right files” 
on page 392.

Checking ownership 
and permissions

Ensure that ownership and permission levels do not change during the system-
level restore.

Backing up a database is useful only if the database is internally consistent. 
Backup always makes sure that a database is in a usable state before it 
proceeds. However, it's a good idea to validate any database before you back it 
up, to ensure that any database you restore is stable. The restore program does 
not check for corruption in the data it is restoring, since the database may not 
even exist. 

To validate your database, issue the following command:

sp_iqcheckdb

You should run 

sp_iqcheckdb

 periodically, and whenever you suspect a 

problem with the database. The sections that follow provide basic information 
on using 

sp_iqcheckdb

. For full details see the Adaptive Server IQ 

Troubleshooting and Error Messages Guide.

This stored procedure works in conjunction with the set option 
DBCC_OPTION. This option should be set to its default value, 0, when you 
run 

sp_iqcheckdb

 for a routine validation before backup.

sp_iqcheckdb

 reads every database page from disk into memory and does 

various consistency checks. For this reason, running this procedure on a large 
database can take a long time. Reading the data consumes most of the 
execution time, so you can estimate how long it will take to run the procedure 
by the size of your database:

10GB

30 minutes

100GB

400 minutes (6 1/2 hours)