Package org.apache.drill.exec.resourcemgr.config.selectors
package org.apache.drill.exec.resourcemgr.config.selectors
Defines all the Selectors which can be assigned to a ResourcePool in the ResourceManagement configuration. A
selector helps to evaluate that given a query and it's metadata if that query can be admitted inside associated
ResourcePool or not. Selectors are associated with both intermediate and leaf level ResourcePools. The intermediate
pool selectors helps to navigate the ResourcePool hierarchy to reach a leaf level ResourcePool where query will
actually be admitted in the queue associated with a leaf pool. Whereas leaf pool selector will help to choose all
the leaf pools which can be considered to admit a query. A selector can be configured for a ResourcePool
using the
ResourcePoolImpl.POOL_SELECTOR_KEY configuration. If the
selector configuration is missing for a ResourcePool then it is associated with a Default Selector making it
a Default ResourcePool. Selectors are configured as a key value pair where key represents it's type and
value is what it uses to evaluate a query. Currently there are 6 different types of supported selectors. In future
more selectos can be supported by implementing
ResourcePoolSelector interface.
DefaultSelector: It acts as a sink and will always return true for all the queries. It is associated with a ResourcePool which is not assigned any selector in the configuration making it a default pool.TagSelector: A selector which has a tag (String) value associated with it. It evaluates all the tags associated with a query to see if there is a match or not. A query is only selected by this selector if it has a tag same as that configured for this selector.AclSelector: A selector which has users/groups policies value associated with it. It evaluates these policies against the users/groups of query session to check if the query can be selected or not. It supports long/short form syntax to configure the acl policies. It also supports * as wildcard character to allow/deny all users/groups in its policies. Please see AclSelector class javadoc for more details.OrSelector: A selector which can have lists of 2 or more other selectors configured as it's value except for Default selector. It performs || operation on the selection result of all other configured selectors.AndSelector: A selector which can have lists of 2 or more other selectors configured as it's value except for Default selector. It performs && operation on the selection result of all other configured selectors.NotEqualSelector: A selector which can have any other selector defined above configured as it's value except for Default selector. It will compare the query metadata against the configured selector and will return ! of that as a selection result. For example: if a TagSelector with value "sales" is configured for this NotSelector then it will select queries whose doesn't have sales tag associated with it.
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ClassDescriptionEvaluates if a query can be admitted to a ResourcePool or not by comparing query user/groups with the configured users/groups policies for this selector.Complex selector whose value is list of other Simple or Complex Selectors.When selector configuration is absent for a ResourcePool then it is associated with a DefaultSelector.Simple selector whose value is another Simple or Complex Selectors.Complex selector whose value is list of other Simple or Complex Selectors.Interface that defines implementation for selectors assigned to a ResourcePool.Simple selector whose value is a string representing a tag.