Designating a Presto connector property as overridable in the QueryGrid portlet allows users to override configured Presto connector properties when starting queries during an individual processing session.
Presto catalogs can define their own properties. You can view these properties using the show session command. This example shows the Presto session property called override in the Presto QueryGrid catalog p2p_active.
presto:default> show session; Name |Value|Default| Type | -------------------+--------------------------------------------------------- p2p_active.override| | | varchar| Properties to p2p_active.override -----------------------------------------------------------+ for QG connector. Of form [name]=[value];[name]=[value];...
- Under Fabric Configuration, select Fabrics.
- Select the fabric.
-
Do one of the following:
Option Description To override a Presto connector property in the Connectors tab - Click the Connectors tab.
- Click
next to the connector that has a property you want to override.
- Select Edit.
- Click
next to Connector Software.
- Find the Presto connector property you want to override and click the Overridable check box.
- Click OK.
- Click Save.
To override a Presto connector property in the Links tab - Click the Links tab.
- Click
next to the link that has a property you want to override.
- Select Edit.
- Click
next to Initiating Connector or Target Connector.
- Find the Presto link property you want to override and click the Overridable check box.
- Click OK.
- Click Save.
-
To override the Presto connector property during a Presto session, use the syntax in the following example.
set session p2p_active.override = ‘<prop1>=<overrideVal1>;<prop2>=<overrideVal2>;…’;
For example:SET SESSION p2p_active.override='responsetimeout = 3000000;linkBufferCount=3;';
presto:default> show session; Name | Value |Default --------------------+---------------------------------------------+------- p2p_active.override| responsetimeout = 3000000;linkBufferCount=3 | | Type | +----------------------------------------------------------------------- |varchar|Properties to override for QG connector. Of form [name]=[value]; --------------- [name]=[value];
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[Optional] To clear Presto connector property overrides without closing a Presto session, use the syntax in the following example.
reset session p2p_active.override;