org.modeshape.jcr.query.engine

Class IndexQueryEngine

java.lang.Object

org.modeshape.jcr.query.engine.ScanningQueryEngine

org.modeshape.jcr.query.engine.IndexQueryEngine

All Implemented Interfaces:

QueryEngine

public class IndexQueryEngine
extends ScanningQueryEngine

A QueryEngine implementation that uses available indexes to more quickly produce query results.

This query engine is capable of producing results for a query by scanning all nodes in the workspace(s) and filtering out any node that does not satisfy the criteria. This scanning is not very efficient and can result in slow queries, especially when the repository is quite large or when the number of nodes that satisfies the query's criteria is a small fraction of all possible nodes in the workspace(s).

This engine can use indexes for certain properties so that it can more quickly identify the nodes that have property values satisfying the constraints of a query. It is possible to index all properties, but this requires significant space and evaluating all constraints using indexes may actually not be the most efficient and fastest approach. This query engine attempts to use a minimum number of indexes that will most quickly produce the set of nodes closest to the actual expected results.

Indexes are access from the repository's IndexProvider instances.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IndexQueryEngine.Builder
protected static class	IndexQueryEngine.ProviderIndexPlanner A IndexPlanner implementation that passes through only those indexes that are owned by the named provider.

Nested classes/interfaces inherited from class org.modeshape.jcr.query.engine.ScanningQueryEngine

ScanningQueryEngine.DynamicOperandFilter, ScanningQueryEngine.PropertyValueExtractor, ScanningQueryEngine.ResultColumns, ScanningQueryEngine.RowFilterSupplier

Field Summary

Fields

Modifier and Type	Field and Description
protected static boolean	DEBUG
protected static Logger	LOGGER We don't use the standard logging convention here; we want clients to easily configure logging for the indexes
protected static boolean	TRACE

Fields inherited from class org.modeshape.jcr.query.engine.ScanningQueryEngine

optimizer, planner, PSEUDO_COLUMN_NAMES, repositoryName

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IndexQueryEngine(ExecutionContext context, String repositoryName, Planner planner, Optimizer optimizer, IndexManager indexManager)

Method Summary

Methods

Modifier and Type	Method and Description
static IndexQueryEngine.Builder	builder() Obtain a builder that can be used to create new query engine instances.
protected NodeSequence	createNodeSequenceForSource(QueryCommand originalQuery, QueryContext context, PlanNode sourceNode, IndexPlan indexPlan, QueryResults.Columns columns, QuerySources sources) Create a node sequence for the given index

Methods inherited from class org.modeshape.jcr.query.engine.ScanningQueryEngine

createExtractFromRow, createExtractFromRow, createExtractReferencesFromRow, createNodeSequence, createNodeSequenceForSource, createQueryContext, createRowFilter, createSortingExtractor, createSortingExtractor, determineProjectedColumns, determineType, execute, executeOptimizedQuery, literalValue, literalValues, shutdown, toRegularExpression, toWildcardExpression

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

protected static final Logger LOGGER

We don't use the standard logging convention here; we want clients to easily configure logging for the indexes

TRACE

protected static final boolean TRACE

DEBUG

protected static final boolean DEBUG

Constructor Detail

IndexQueryEngine

protected IndexQueryEngine(ExecutionContext context,
                String repositoryName,
                Planner planner,
                Optimizer optimizer,
                IndexManager indexManager)

Method Detail

builder

public static IndexQueryEngine.Builder builder()

Obtain a builder that can be used to create new query engine instances.

Returns:

the builder; never null

createNodeSequenceForSource

protected NodeSequence createNodeSequenceForSource(QueryCommand originalQuery,
                                       QueryContext context,
                                       PlanNode sourceNode,
                                       IndexPlan indexPlan,
                                       QueryResults.Columns columns,
                                       QuerySources sources)

Description copied from class: ScanningQueryEngine

Create a node sequence for the given index

Overrides:

createNodeSequenceForSource in class ScanningQueryEngine

Parameters:

originalQuery - the original query command; may not be null

context - the context in which the query is to be executed; may not be null

sourceNode - the PlanNode.Type.SOURCE plan node for one part of a query; may not be null

indexPlan - the IndexPlan specification; may not be null

columns - the result column definition; may not be null

sources - the query sources for the repository; may not be null

Returns:

the sequence of results; null only if the type of index is not understood