Procedure documentationChecking Database Structures Locate this document in the navigation structure


You check whether the database structures are consistent, the keys have the correct length, and the keys are sorted in ascending order.

Recommendation Recommendation

Check the database structures once a week.

Checking the database structure is CPU-intensive and time-consuming because the system carries out many I/O operations. In your production system, schedule database structure checks only at times when the load on the database system is low, or carry out the checks on a copy of the current database.

More information: Database Administration, Database Copy

End of the recommendation.


You are logged on to the database as database system administrator or as a DBM operator.


  1. Select the database in the explorer tree.

  2. In the context menu of the database, choose   Administration Tasks   Check Database Structure...  

  3. Select the check procedure.

    Procedures for Checking Database Structures



    Operational State


    Check database structures in operational state ONLINE

    Except Indexes: Indexes are not checked. This option usually speeds up the check.


    The database system checks the structural consistency of all the tables, indexes, LOB columns and so on, in the cache and the data area.

    The database system does a complete run through all B* trees and page chains. It checks whether all the pages of the B* trees and page chains can be accessed and whether the administration structures (for example the separators on the B* tree index level) on the pages are intact.

    Whenever the database system reads a data page from the data area, it calculates a checksum that has to match the checksum saved on the data page.

    In addition, it also checks the key length and whether it is sorted in ascending order, among other things.

    Check database structures and clear converter in operational state ADMIN



    The database system initially executes the same checks as in the ONLINE operational state.

    Afterwards, the database system cleans the converter on the basis of the results: It deletes all pages it did not read during the check, which are the pages that no longer exist in the database.

    Check database structure for a selected table in operational state ONLINE

    With Long Check: If the base table to be checked contains LOB columns, the system checks whether all the LOB values defined actually exist. To ensure the consistency of the transaction, an SQL share lock is requested for the duration of the check.

    Catalog: The database catalog for this table is checked. This option cannot be combined with the Extended or With Long Check options.


    You check a specific table.

    The database system performs the same checks as during the check of the entire database in the ONLINE operational state.


If the system finds errors, it writes them to the Database Errors log file (kernel log file).

More information: Displaying Configuration and Log Files

More Information

Database Administration, Checking Database Structures