SAP DB Interview Questions and Answers
Question - 81 : - What Do I Do If There Are No Free Database Sessions Left, And No New Database Application Can Log On To The Database?
Answer - 81 : -
The general parameter MAXUSERTASKS defines the maximum number of user tasks that can be active at the same time, and therefore determines the maximum number of database sessions.
When this number is reached, no further users can log on to this database instance. You then need to increase the parameter. If you assign a very high value to MAXUSERTASKS, then the database system requires a lot of address room, especially in the case of local communication using shared memory.
Question - 82 : - What Do I Do If The Data Area Is Full?
Answer - 82 : -
When there is no more memory available in the database, the database hangs. You must make free memory available in the form of a new data volume. You can add new volumes while the database is online.
Question - 83 : - Does Maxdb Support The Use Of External Backup Tools?
Answer - 83 : -
Yes. Max DB supports a number of backup tools from third parties, such as Networker, Netbackup from Veritas, and so on.
Which specific tools are supported, and how they can be included in a MaxDB environment is described in the MaxDB documentation (Note 767598). Search the glossary for the keyword "external backup tool".
Scripts in the database manager also enable you to use all other backup tools that are able to process backups from pipes.
Question - 84 : - What Advantage Does A Backup Using The Maxdb Backup Tool Offer Compared To A File System Backup?
Answer - 84 : -
It is only possible to execute a file system backup when the database is in the offline status. The length of time for which the database is unavailable for operation depends on the size of the dataset.
In contrast, you can back up the database while it is in the online status using the MaxDB backup tools, in parallel with production operation. You can use a backup generated online using database tools for a system copy.
A file system backup of the volumes (data and log) backs up all data that is saved in the volume.
In contrast, a backup using the MaxDB tools only backs up the data of a converter version, which may be required for a recovery.
When you create a file system backup, the system does not carry out a checksum-check on the blocks.
While the backup is being created using the MaxDB tools, the system executes consistency checks on the data.
Even when you back up the log volumes using a file system backup, you need to also back up the log area using the database tools, to ensure that the log area can be released again for overwriting.
A file system backup is not included in the MaxDB backup history.
Backups performed using the MaxDB tools integrate the backup history, and this makes restoring the database in the event of a recovery a simple process.
Question - 85 : - Are Logs Also Saved During A Database Backup?
Answer - 85 : -
No. A database backup using the MaxDB tools only backups up the data that is stored in the data volumes. This includes the actual use data and the "before images", so that it is possible to restore a consistent database using only the database backup.
The data that is saved in the log volume is not backed up during a data backup.
Question - 86 : - How Do I Perform A Database Backup?
Answer - 86 : -
To perform a database backup, use the MaxDB backup tools DBMGUI or DBMCLI. You can use the scheduling calendar (DB13 or DB13C) to schedule a backup for a particular point in time and execute it implicitly.
It is possible to execute file system backups of MaxDB volumes when the database is offline only, though we recommend this only in exceptional circumstances (such as if you use snapshots or split-mirrors).
Question - 87 : - What Is The Central Scheduling Calendar?
Answer - 87 : -
The central CCMS scheduling calendar comprises transactions DB13 and DB13C.
You can use these transactions to schedule the following activities:
- Back up the dataset area and the log area
- Check backups for completeness
- Update the optimizer statistics
- Database structure checks
Question - 88 : - Is There A Central Transaction In The Sap System For All Administrative Database Activities?
Answer - 88 : -
In the MaxDB environment, you can use the transaction DB50: Database Assistant to monitor the database.
You can use transaction LC10: liveCache Assistant to monitor a liveCache. In SAP Releases as of Release 7.0, you access these transactions using transaction DB59.
As of SAP Release 7.0 the DBA Cockpit (transaction dbacockpit) is available as a central access to the database or liveCache administration.
Question - 89 : - Can Administration Tasks Be Automated?
Answer - 89 : -
You can use the CCMS scheduling calendar or the MaxDB tools to automate both administration tasks that need to run regularly (such as automatic log backups, Update Statistics) or that only need to be run when required (such as extending the data area).
Question - 90 : - What Administration Tools Are Available?
Answer - 90 : -
SAP recommends that you use the MaxDB tools DBMGUI/Database Studio, DBMCLI and SAP CCMS for the administration tasks.