org.apache.lens.server.api.driver.hooks

Class QueryCostBasedQueryHook<T extends QueryCost<T>>

java.lang.Object

org.apache.lens.server.api.driver.hooks.NoOpDriverQueryHook

org.apache.lens.server.api.driver.hooks.QueryCostBasedQueryHook<T>

All Implemented Interfaces:

DriverQueryHook

public class QueryCostBasedQueryHook<T extends QueryCost<T>>
extends NoOpDriverQueryHook

This hook allows for a driver to discard queries based on the cost of the query. This works on two configurations values, among which either, both or none can be set. The configuration values are picked from driver configuration. The driver config can set `allowed.range.sets` as a mathematical range of costs that are allowed on this driver. Queries having cost among these will be allowed and the rest will be discarded. On the other hand, the driver can set `disallowed.range.sets` as a mathematical range of costs that are disallowed on this driver. Queries having range among these will be rejected, and the rest will be allowed. Mathematical range looks like the following: (10, 20] U (30, 40) U [1000, )

Field Summary

Fields

Modifier and Type	Field and Description
static String	ALLOWED_RANGE_SETS
static String	DISALLOWED_RANGE_SETS

Constructor Summary

Constructors

Constructor and Description
QueryCostBasedQueryHook()

Method Summary

Modifier and Type	Method and Description
com.google.common.collect.RangeSet<T>	parseAllowedRangeSet(String rangeStr)
com.google.common.collect.RangeSet<T>	parseDisallowedRangeSet(String rangeStr)
com.google.common.collect.Range<T>	parseRange(String rangeStr)
com.google.common.collect.RangeSet<T>	parseRangeSet(String rangeStr)
void	postEstimate(AbstractQueryContext ctx) Called just after a successful estimate operation is tried on this driver
void	setDriver(LensDriver driver) This setter method is called by the driver once hook instance is created.

Methods inherited from class org.apache.lens.server.api.driver.hooks.NoOpDriverQueryHook

getDriver, postDriverSelection, postRewrite, preEstimate, preLaunch, preRewrite

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ALLOWED_RANGE_SETS

public static final String ALLOWED_RANGE_SETS

See Also:

Constant Field Values

DISALLOWED_RANGE_SETS

public static final String DISALLOWED_RANGE_SETS

See Also:

Constant Field Values

Constructor Detail

QueryCostBasedQueryHook

public QueryCostBasedQueryHook()

Method Detail

parseAllowedRangeSet

public com.google.common.collect.RangeSet<T> parseAllowedRangeSet(String rangeStr)

parseDisallowedRangeSet

public com.google.common.collect.RangeSet<T> parseDisallowedRangeSet(String rangeStr)

parseRangeSet

public com.google.common.collect.RangeSet<T> parseRangeSet(String rangeStr)

parseRange

public com.google.common.collect.Range<T> parseRange(String rangeStr)

setDriver

public void setDriver(LensDriver driver)

Description copied from interface: DriverQueryHook

This setter method is called by the driver once hook instance is created. This driver information can be used while extracting driver specific information form the QueryContext.

Specified by:

setDriver in interface DriverQueryHook

Overrides:

setDriver in class NoOpDriverQueryHook

postEstimate

public void postEstimate(AbstractQueryContext ctx)
                  throws LensException

Description copied from interface: DriverQueryHook

Called just after a successful estimate operation is tried on this driver

Specified by:

postEstimate in interface DriverQueryHook

Overrides:

postEstimate in class NoOpDriverQueryHook

Throws:

LensException