Databank Check Option
Whenever a database is started, its databanks are checked to find out if they were properly closed when it went down. If a databank is found that was not properly closed, an internal check is performed on it. This parameter controls whether both the index and data pages of a databank are checked, or just the index pages. Checking just the index pages is faster but any corruption in the data pages will not be detected.
When immediate options are used the check is performed in the background while allowing concurrent access to the database data. The Immediate restart options require a license key called Imm Restart.
| DbCheck Option | Description |
|---|---|
| Check index pages only | Index pages only are checked in the foreground while applications that access the databank waits for the operation to complete. |
| Check all pages | A full databank check (involving index and data pages) provides for more secure operations, but may take much longer to execute than an index page check. When a full check is done, the index pages are checked in the foreground and the data pages are checked in the background so there is a smaller effect on performance. |
| Immediate, no check | This options performs no checking when the file is opened. The system still verifies the integrity of each page through a checksum. A few pages may have been preallocated and these are not reclaimed when this option is used. If the option is subsequently changed these pages will be reclaimed the next time the databank is opened. |
| Immediate, check index pages | This option performs a check of all index pages in the databank in the background. This is done concurrently with other operations on the system. |
| Immediate, check all pages | This option performs a check of all pages in the databank in the background. This is done concurrently with other operations on the system. |
See Also