io.druid.query.datasourcemetadata

Class DataSourceQueryQueryToolChest

java.lang.Object

io.druid.query.QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

io.druid.query.datasourcemetadata.DataSourceQueryQueryToolChest

public class DataSourceQueryQueryToolChest
extends QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Constructor Summary

Constructors

Constructor and Description
DataSourceQueryQueryToolChest()

Method Summary

Methods

Modifier and Type	Method and Description
<T extends LogicalSegment> List<T>	filterSegments(DataSourceMetadataQuery query, List<T> segments) This method is called to allow the query to prune segments that it does not believe need to actually be queried.
CacheStrategy	getCacheStrategy(DataSourceMetadataQuery query) Returns a CacheStrategy to be used to load data into the cache and remove it from the cache.
com.google.common.collect.Ordering<Result<DataSourceMetadataResultValue>>	getOrdering()
com.fasterxml.jackson.core.type.TypeReference<Result<DataSourceMetadataResultValue>>	getResultTypeReference() Returns a TypeReference object that is just passed through to Jackson in order to deserialize the results of this type of query.
com.metamx.emitter.service.ServiceMetricEvent.Builder	makeMetricBuilder(DataSourceMetadataQuery query) Creates a builder that is used to generate a metric for this specific query type.
com.google.common.base.Function<Result<DataSourceMetadataResultValue>,Result<DataSourceMetadataResultValue>>	makePreComputeManipulatorFn(DataSourceMetadataQuery query, MetricManipulationFn fn) Creates a Function that can take in a ResultType and return a new ResultType having applied the MetricManipulatorFn to each of the metrics.
QueryRunner<Result<DataSourceMetadataResultValue>>	mergeResults(QueryRunner<Result<DataSourceMetadataResultValue>> runner) This method wraps a QueryRunner.
com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>	mergeSequences(com.metamx.common.guava.Sequence<com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences) This method doesn't belong here, but it's here for now just to make it work.
com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>	mergeSequencesUnordered(com.metamx.common.guava.Sequence<com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences) This method doesn't belong here, but it's here for now just to make it work.

Methods inherited from class io.druid.query.QueryToolChest

makePostComputeManipulatorFn, postMergeQueryDecoration, preMergeQueryDecoration

Methods inherited from class java.lang.Object

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

Constructor Detail

DataSourceQueryQueryToolChest

public DataSourceQueryQueryToolChest()

Method Detail

filterSegments

public <T extends LogicalSegment> List<T> filterSegments(DataSourceMetadataQuery query,
                                                List<T> segments)

Description copied from class: QueryToolChest

This method is called to allow the query to prune segments that it does not believe need to actually be queried. It can use whatever criteria it wants in order to do the pruning, it just needs to return the list of Segments it actually wants to see queried.

Overrides:

filterSegments in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Type Parameters:

T - A Generic parameter because Java is cool

Parameters:

query - The query being processed

segments - The list of candidate segments to be queried

Returns:

The list of segments to actually query

mergeResults

public QueryRunner<Result<DataSourceMetadataResultValue>> mergeResults(QueryRunner<Result<DataSourceMetadataResultValue>> runner)

Description copied from class: QueryToolChest

This method wraps a QueryRunner. The input QueryRunner, by contract, will provide a series of ResultType objects in time order (ascending). This method should return a new QueryRunner that potentially merges the stream of ordered ResultType objects.

Specified by:

mergeResults in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

runner - A QueryRunner that provides a series of ResultType objects in time order (ascending)

Returns:

a QueryRunner that potentialy merges the stream of ordered ResultType objects

mergeSequences

public com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>> mergeSequences(com.metamx.common.guava.Sequence<com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences)

Description copied from class: QueryToolChest

This method doesn't belong here, but it's here for now just to make it work. The method needs to take a Sequence of Sequences and return a single Sequence of ResultType objects in time-order (ascending) This method assumes that its input sequences provide values already in sorted order. Even more specifically, it assumes that the individual sequences are also ordered by their first element. In the vast majority of cases, this should just be implemented with: return new OrderedMergeSequence<>(getOrdering(), seqOfSequences);

Specified by:

mergeSequences in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

seqOfSequences - sequence of sequences to be merged

Returns:

the sequence of merged results

mergeSequencesUnordered

public com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>> mergeSequencesUnordered(com.metamx.common.guava.Sequence<com.metamx.common.guava.Sequence<Result<DataSourceMetadataResultValue>>> seqOfSequences)

Description copied from class: QueryToolChest

This method doesn't belong here, but it's here for now just to make it work. The method needs to take a Sequence of Sequences and return a single Sequence of ResultType objects in time-order (ascending) This method assumes that its input sequences provide values already in sorted order, but, unlike mergeSequences, it does *not* assume that the individual sequences are also ordered by their first element. In the vast majority if ocases, this hsould just be implemented with: return new MergeSequence<>(getOrdering(), seqOfSequences);

Specified by:

mergeSequencesUnordered in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

seqOfSequences - sequence of sequences to be merged

Returns:

the sequence of merged results

makeMetricBuilder

public com.metamx.emitter.service.ServiceMetricEvent.Builder makeMetricBuilder(DataSourceMetadataQuery query)

Description copied from class: QueryToolChest

Creates a builder that is used to generate a metric for this specific query type. This exists to allow for query-specific dimensions on metrics. That is, the ToolChest is expected to set some meaningful dimensions for metrics given this query type. Examples might be the topN threshhold for a TopN query or the number of dimensions included for a groupBy query.

Specified by:

makeMetricBuilder in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

query - The query that is being processed

Returns:

A MetricEvent.Builder that can be used to make metrics for the provided query

makePreComputeManipulatorFn

public com.google.common.base.Function<Result<DataSourceMetadataResultValue>,Result<DataSourceMetadataResultValue>> makePreComputeManipulatorFn(DataSourceMetadataQuery query,
                                                                                                                                       MetricManipulationFn fn)

Description copied from class: QueryToolChest

Creates a Function that can take in a ResultType and return a new ResultType having applied the MetricManipulatorFn to each of the metrics. This exists because the QueryToolChest is the only thing that understands the internal serialization format of ResultType, so it's primary responsibility is to "decompose" that structure and apply the given function to all metrics. This function is called very early in the processing pipeline on the Broker.

Specified by:

makePreComputeManipulatorFn in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

query - The Query that is currently being processed

fn - The function that should be applied to all metrics in the results

Returns:

A function that will apply the provided fn to all metrics in the input ResultType object

getResultTypeReference

public com.fasterxml.jackson.core.type.TypeReference<Result<DataSourceMetadataResultValue>> getResultTypeReference()

Description copied from class: QueryToolChest

Returns a TypeReference object that is just passed through to Jackson in order to deserialize the results of this type of query.

Specified by:

getResultTypeReference in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Returns:

A TypeReference to indicate to Jackson what type of data will exist for this query

getCacheStrategy

public CacheStrategy getCacheStrategy(DataSourceMetadataQuery query)

Description copied from class: QueryToolChest

Returns a CacheStrategy to be used to load data into the cache and remove it from the cache. This is optional. If it returns null, caching is effectively disabled for the query.

Overrides:

getCacheStrategy in class QueryToolChest<Result<DataSourceMetadataResultValue>,DataSourceMetadataQuery>

Parameters:

query - The query whose results might be cached

Returns:

A CacheStrategy that can be used to populate and read from the Cache

getOrdering

public com.google.common.collect.Ordering<Result<DataSourceMetadataResultValue>> getOrdering()