<vdb name="{vdb-name}" version="1">
<model name="{model-name}" type="VIRTUAL">
<metadata type="{jboss-as-module-name}"></metadata>
</model>
</vdb>Runtime Updates
Teiid supports several mechanisms for updating the runtime system.
Data Updates
Data change events are used by Teiid to invalidate result set cache entries. Result set cache entries are tracked by the tables that contributed to their results. By default Teiid will capture internal data events against physical sources and distribute them across the cluster. This approach has several limitations. First updates are scoped only to their originating VDB/version. Second updates made out side of Teiid are not captured. To increase data consistency external change data capture tools can be used to send events to Teiid. From within a Teiid cluster the org.teiid.events.EventDistributorFactory and org.teiid.events.EventDistributor can be used to distribute change events. The EventDistributorFactory can be looked up by its name "teiid/event-distributor-factory". See Programmatic Control for a dataModification example.
When externally capturing all update events, "detect-change-events" property in the teiid subsystem in can be set to false, to not duplicate change events. By default, this property is set to true.
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Note
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Using the org.teiid.events.EventDistributor interface you can also update runtime metadata. Please check the API.
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The use of the other EventDistributor methods to manually distribute other events is not always necessary. Check the System Procedures for SQL based updates.
Runtime Metadata Updates
Runtime updates via system procedures and DDL statements are by default ephemeral. They are effective across the cluster only for the currently running vdbs. With the next vdb start the values will revert to whatever is stored in the vdb. Updates may be made persistent though by configuring a org.teiid.metadata.MetadataRepository. An instance of a MetadataRepository can be installed via the vdb.xml file in the META-INF directory or use a VDB file as below.
In the above code fragment, replace the {jboss-as-module-name} with a WildFly module name that has library that implements the org.teiid.metadata.MetadataRepository interface and defines file "META-INF/services/org.teiid.metadata.MetadataRepository" with name of the implementation file.
The MetadataRepository repository instance may fully implement as many of the methods as needed and return null from any unneeded getter.
It is not recommended to directly manipulate org.teiid.metadata.AbstractMetadataRecord instances. System procedures and DDL statements should be used instead since the effects will be distributed through the cluster and will not introduce inconsistencies.
org.teiid.metadata.AbstractMetadataRecord objects passed to the MetadataRepository have not yet been modified. If the MetadataRepository cannot persist the update, then a RuntimeException should be thrown to prevent the update from being applied by the runtime engine.
The MetadataRepository can be accessed by multiple threads both during load or at runtime with through DDL statements. Your implementation should handle any needed synchronization.
Costing Updates
See the Reference for the system procedures SYSADMIN.setColumnStats and SYSADMIN.setTableStats. To make costing updates persistent MetadataRepository implementations should be provided for:
TableStats getTableStats(String vdbName, String vdbVersion, Table table);
void setTableStats(String vdbName, String vdbVersion, Table table, TableStats tableStats);
ColumnStats getColumnStats(String vdbName, String vdbVersion, Column column);
void setColumnStats(String vdbName, String vdbVersion, Column column, ColumnStats columnStats);Schema Updates
See the Reference for supported DDL statements. To make schema updates persistent implementations should be provided for:
String getViewDefinition(String vdbName, String vdbVersion, Table table);
void setViewDefinition(String vdbName, String vdbVersion, Table table, String viewDefinition);
String getInsteadOfTriggerDefinition(String vdbName, String vdbVersion, Table table, Table.TriggerEvent triggerOperation);
void setInsteadOfTriggerDefinition(String vdbName, String vdbVersion, Table table, Table.TriggerEvent triggerOperation, String triggerDefinition);
boolean isInsteadOfTriggerEnabled(String vdbName, String vdbVersion, Table table, Table.TriggerEvent triggerOperation);
void setInsteadOfTriggerEnabled(String vdbName, String vdbVersion, Table table, Table.TriggerEvent triggerOperation, boolean enabled);
String getProcedureDefinition(String vdbName, String vdbVersion, Procedure procedure);
void setProcedureDefinition(String vdbName, String vdbVersion, Procedure procedure, String procedureDefinition);
LinkedHashMap<String, String> getProperties(String vdbName, String vdbVersion, AbstractMetadataRecord record);
void setProperty(String vdbName, String vdbVersion, AbstractMetadataRecord record, String name, String value);