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 QueryIndexProvider instances.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IndexQueryEngine.Builder

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, Map<String,QueryIndexProvider> indexProvidersByName)

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
QueryContext	createQueryContext(ExecutionContext context, RepositoryCache repositoryCache, Set<String> workspaceNames, Map<String,NodeCache> overriddenNodeCachesByWorkspaceName, Schemata schemata, NodeTypes nodeTypes, BufferManager bufferManager, PlanHints hints, Map<String,Object> variables) Create a new context for query execution.
QueryIndexWriter	getQueryIndexWriter() Get the interface for updating the indexes.
void	shutdown() Signal that the engine is no longer needed and should clean up and/or close any resources.

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

createExtractFromRow, createExtractFromRow, createExtractReferencesFromRow, createNodeSequence, createNodeSequenceForSource, createRowFilter, createSortingExtractor, createSortingExtractor, determineProjectedColumns, determineType, execute, executeOptimizedQuery, literalValue, literalValues, 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,
                Map<String,QueryIndexProvider> indexProvidersByName)

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

shutdown

public void shutdown()

Description copied from interface: QueryEngine

Signal that the engine is no longer needed and should clean up and/or close any resources.

Specified by:

shutdown in interface QueryEngine

Overrides:

shutdown in class ScanningQueryEngine

createQueryContext

public QueryContext createQueryContext(ExecutionContext context,
                              RepositoryCache repositoryCache,
                              Set<String> workspaceNames,
                              Map<String,NodeCache> overriddenNodeCachesByWorkspaceName,
                              Schemata schemata,
                              NodeTypes nodeTypes,
                              BufferManager bufferManager,
                              PlanHints hints,
                              Map<String,Object> variables)

Description copied from interface: QueryEngine

Create a new context for query execution.

Specified by:

createQueryContext in interface QueryEngine

Overrides:

createQueryContext in class ScanningQueryEngine

Parameters:

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

repositoryCache - the repository cache that should be used to load results; may be null if no results are to be loaded

workspaceNames - the name of each workspace to be queried, or an empty set if all the workspaces should be queried; may not be null

overriddenNodeCachesByWorkspaceName - the NodeCache instances that should be used to load results, which will be used instead of the RepositoryCache's NodeCache for a given workspace name; may be null or empty

schemata - the schemata

nodeTypes - the snapshot of node types; may not be null

bufferManager - the buffer manager; may not be null

hints - the hints, or null if there are no hints

variables - the mapping of variables and values, or null if there are no such variables

Returns:

the context; never null

getQueryIndexWriter

public QueryIndexWriter getQueryIndexWriter()

Description copied from interface: QueryEngine

Get the interface for updating the indexes.

Specified by:

getQueryIndexWriter in interface QueryEngine

Overrides:

getQueryIndexWriter in class ScanningQueryEngine

Returns:

the indexing interface; 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