System::getDatabaseStats Method

Signature getDatabaseStats(jdo: JadeDynamicObject input);

The System class provides the getDatabaseStats method returns statistics relating to persistent database activity.

The values returned in the dynamic object specified by the jdo parameter are described in the following table. Properties are null at the initiation of the database server node and are applicable only to the running database instance for the lifetime of the database server node. Where properties hold cumulative values (fileOpens, checkPoints, and so on), JADE applications will need to compare values from one call to the next, to work out the value differences.

The properties returned in the dynamic object are listed in the following table.

Property	Type	Description
fileOpens	Integer64	The number of database file open operations performed
fileCloses	Integer64	The number of database file close operations performed
committedTrans	Integer64	The number of transactions committed to the database
abortedTrans	Integer64	The number of transactions aborted
checkPoints	Integer64	The number of database checkpoints that have taken place
lastCheckPointDate	Date	The date of the last checkpoint taken
lastCheckPointTime	Time	The time of the last checkpoint taken
lastCheckPointDuration	Integer64	The time in milliseconds for the last checkpoint taken
maxCheckPointDuration	Integer64	The maximum time in milliseconds for any checkpoint taken
avgCheckPointDuration	Integer64	The average time in milliseconds for any checkpoint taken
editionGets	Integer64	The number of getEdition operations performed
objectGets	Integer64	The number of getObject operations performed
objectCreates	Integer64	The number of objects created
objectUpdates	Integer64	The number of objects updated
objectDeletes	Integer64	The number of objects deleted
dirtyReads	Integer64	The number of dirty reads
osmReads	Integer64	The number of reads of a previously committed edition
priorEditionReads	Integer64	The number of reads requiring fetch of a previously committed edition from the journal
absentCollGets	Integer64	The number of osmReads for collection headers
overflowDeleteGets	Integer64	The number of osmReads by the deleting transaction

Properties are added to the object when the method is first called. The object can then be used in subsequent calls.

If the dynamic object passed to the method already contains properties that do not match the properties to be returned, the existing dynamic object properties are removed and replaced with the appropriate properties. This method is most efficient when the properties match those to be returned.

For an example of the use of and output from this method, see the System class getDatabaseStats method in Volume 2 of the JADE Encyclopaedia of Classes.