## Fixing Errors in the Data Structure

### Use

After a database structure check, you analyze the errors and attempt to correct them.

### Prerequisites

You have checked the data structures.

### Procedure

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1. Display the kernel log (see Log Files).

In the kernel log, the start of the database structure check is marked with the keyword CHECK, followed by the results of the database structure check and any errors.

Typical error message:

2005-04-08 09:40:30 0x37C ERR 53019 CHECK Base error: bad_datapage

2005-04-08 09:40:30 0x37C ERR 53019 CHECK Root pageNo: 104236

2. For each error, identify the number of the root page (ROOT) of the respective B* tree; or for SAP liveCache data, the root page of the respective page chain.

3. Use the ROOTS system table, or for SAP liveCache data the CLASSCONTAINER_ROOTS system table, to infer the affected base table or the affected index from the number of the root page (see the Reference Manual, Analyzing System Tables).

4. If the error has affected an index, restore the damaged index. See

○ Database Manager GUI, Restoring Indexes After Database Restore

○ Database Manager CLI, sql_recreateindex

○ Database Administration in CCMS: MaxDB, Index Analysis

5. If the error affects a base table, you have the following options:

○ You delete the base table. You can try to reconstruct the base table from other tables.

○ You restore the database instance using the Database Manager. To do this, you use the backup that was created before the last successful database structure check.

6. If you had not yet done a database structure check for the database instance, then perform another database structure check for the table that was damaged after you import the backup. If the database system finds errors again, then import an older backup. See

○ Database Manager GUI, Restoring from an Earlier Backup

○ Database Manager CLI, recover_start

### Example

Example: Error in the Data Structure