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.