This menu function displays the most important events and activities of the ADABAS server, showing summarized information about the states of the data buffers, the number and type of the commands processed by the ADABAS server, the applied search strategies, the state of lock synchronization, and the activities of the logging process.
Example:
On the first page, the display contains the following information about the ADABAS caches:
- Total number of accesses, successful and unsuccessful accesses to the ADABAS data cache as well as the percentage of successful accesses
(Data)
Accesses to the buffers (caches) are shown in the same way for
- the Catalog
- the converter
- the temporary data cache (Temporary)
The hit rate for the cache areas indicates whether the configured size of these areas is sufficient. The data cache and the converter cache hit rate is especially important. It should be as close to 100% as possible. Values under 70% are insufficient and a sign of bad performance.
In the following, information about the processed SQL statements is shown:
- Number of SQL statements
(SQL Commands)
- Number of ROLLBACKs
(Rollbacks)
- Number of COMMITs
(Commits)
From the number of COMMITs and ROLLBACKs results the number of transactions.
- Number of dynamic SQL statements
(Prepares)
- Number of executions of dynamic SQL statements
(Executes)
- Number of SQL statements for the creation of database objects
(Creates)
- Number of SQL statements for the alteration of database objects
(Alters)
- Number of SQL statements for the dropping of database objects
(Drops)
- Number of sequential read commands through the catalog
(Catalog scans)
The next section shows the I/O activities:
- Number of physical reads
(Physical reads)
- Number of physical writes
(Physical writes)
- Number of logical reads
(Logical reads)
- Number of logical writes
(Logical writes)
The following information about the locking activities is output:
- Maximum number of lock entries available
(Entries available)
The maximum number of available lock entries can be specified using the MAXLOCKS system parameter (see Section Installing a New Serverdb, "configuration parameters") of the Configuration / Alter Parameters / Kernel menu function .
- Maximum number of entries used in the lock list
(Entries, Max. Used)
- Average number of entries used in the lock list
(Entries, Avg. Used)
- Number of active lock holders
(Lock holder)
- Number of current lock requests
(Lock requester)
- Total number of row locks set
(Row locks )
- Number of table locks set
(Table locks )
- Number of lock collisions
(Collisions)
- Number of lock escalations
(Escalations)
The number of lock collisions and lock escalations in relation to the total number of locks shows whether the chosen number of configured lock entries is sufficient for the database tasks.
In the next section, some essential information about the logging activities is output:
- Number of log pages written
(Logpages written)
The number of log pages written is an expression of the modifying activities on the database. In normal database work, the log devspace is the most I/O intensive area.
- Number of wait states for log write operations
(Waits for logwriter)
- Number of group commits
(Group commits)
If a transaction is completed, then, before writing the actual commit, a check is made as to whether other transactions have reached a commit as well. If so, the writing of the commits for the transactions is done in a single I/O operation.
- Number of log queue overflows
(Log queue overflows)
In the last section, statistics about successful scan and sort activities are output:
- Number of sequential scans through the whole base table
(Table Scans)
Sequential scans are the slowest search operations. Too frequent scanning can be a sign of poor database design. The creation of additional indexes on the respective tables could be the remedy.
- Number of scans for which an index was read sequentially without accessing base table rows
(Index Scans)
- Number of sorts within the cache
(Cache sorts)
- Number of sorts within rows after an insert
(Row sorts)