AST2BOpContext (Blazegraph Database Platform 2.1.5 API)

java.lang.Object
- com.bigdata.rdf.sparql.ast.eval.AST2BOpContext

All Implemented Interfaces:

IdFactory, IEvaluationContext

Direct Known Subclasses:

AST2BOpUpdateContext
```
public class AST2BOpContext
extends Object
implements IdFactory, IEvaluationContext
```
Convenience class for passing around the various pieces of context necessary to construct the bop pipeline.

Field Summary

Fields
Modifier and Type	Field and Description
`int`	`accessPathSampleLimit` The #of samples to take when comparing the cost of a SCAN with an IN filter to as-bound evaluation for each graph in the data set.
`boolean`	`accessPathScanAndFilter` For named and default graph access paths where access path cost estimation is disabled by setting the `accessPathSampleLimit` to ZERO (0), this determines whether a SCAN + FILTER or PARALLEL SUBQUERY (aka as-bound data set join) approach.
`ASTContainer`	`astContainer` The `ASTContainer` and never `null`.
`boolean`	`constructDistinctSPO` Set by the `ConstructDistinctSPOHint`.
`BOpContextBase`	`context` Factory for resolving relations and access paths used primarily by `AST2BOpJoins`s.
`protected AbstractTripleStore`	`db` The KB instance.
`boolean`	`defaultGraphDistinctFilter` Whether or not a distinct filter is applied over triples extracted from the default graph (applies in quads mode only).
`IDescribeCache`	`describeCache` The `IDescribeCache` -or- `null` iff that cache is not enabled..
`IExternalAST2BOp`	`gpuEvaluation` The `IExternalAST2BOp` for using GPUs or `null`.
`int`	`maxParallelForSolutionSetHashJoin` The maximum parallelism for a solution set hash join when the join is used in a context that does permit parallelism, such as sub-group and sub-query evaluation (default ).
`boolean`	`mergeJoin` When `true`, a merge-join pattern will be recognized if it appears in a join group.
`boolean`	`nativeDistinctSolutions` When `true`, will use the version of the DISTINCT SOLUTIONS operator which uses the `HTree` against the native heap.
`boolean`	`nativeDistinctSPO` When `true`, may use the version of DISTINCT which operates on the native heap (this is only used when we are doing a hash join against a default graph access path and the predicate for that access path has a large cardinality).
`long`	`nativeDistinctSPOThreshold` The threshold at which we will use a native hash set rather than a default hash set for a default graph access path.
`boolean`	`nativeHashJoins` When `true`, use hash index operations based on the `HTree`.
`ASTOptimizerList`	`optimizers` The query optimizers (this includes both query rewrites for correct semantics, such as a rewrite of a DESCRIBE query into a CONSTRUCT query, and query rewrites for performance optimizations).
`boolean`	`pipelinedHashJoins` When `true`, use pipelined hash join operations wherever possible.
`QueryEngine`	`queryEngine` The `QueryEngine`.
`IChunkHandler`	`queryEngineChunkHandler` Controls whether the intermediate solution chunks on the query engine operator input queues are stored on the native heap and/or the managed object heap.
`Properties`	`queryHints` The query hints from the original `#query`.
`UUID`	`queryId` The unique identifier assigned to this query.
`boolean`	`remoteAPs` When `true`, force the use of REMOTE access paths in scale-out joins.
`ISolutionSetManager`	`solutionSetManager` The `ISolutionSetManager` -or- `null` iff that cache is not enabled.

Constructor Summary

Constructors
Constructor and Description

AST2BOpContext(ASTContainer astContainer, AbstractTripleStore db)

Constructors
Constructor and Description
`AST2BOpContext(ASTContainer astContainer, AbstractTripleStore db)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addQueryAttribute(Object key, Object val)`
`String`	`createVar(String prefix)` Create a new variable name which is unique within the scope of this `AST2BOpContext`.
`AbstractTripleStore`	`getAbstractTripleStore()` Return the database.
`BOpContextBase`	`getBOpContext()` Return the context for evaluation of `IValueExpression`s during query optimization.
`IDescribeCache`	`getDescribeCache()` Return the cache for described resources (experimental feature).
`int`	`getDescribeIterationLimit(ProjectionNode projection)` Return the effective iteration limit for a DESCRIBE query.
`DescribeModeEnum`	`getDescribeMode(ProjectionNode projection)` Return the effective `DescribeModeEnum`.
`int`	`getDescribeStatementLimit(ProjectionNode projection)` Return the effective statement limit for a DESCRIBE query.
`Set<IVariable<?>>`	`getGloballyScopedVariables()` Returns all the variables with a global scope.
`String`	`getLexiconNamespace()` Return the namespace of the `LexiconRelation`.
`long`	`getLexiconReadTimestamp()` Return the timestamp which will be used to read on the lexicon.
`String`	`getNamespace()` Return the namespace of the `AbstractTripleStore`.
`Map<Object,Object>`	`getQueryAttributes()` Return an optional (and immutable) map of key-value pairs that will be attached to the `IRunningQuery` on the query controller node.
`ISolutionSetManager`	`getSolutionSetManager()` Return the manager for named solution sets (experimental feature).
`ISolutionSetStats`	`getSolutionSetStats()` Some summary statistics about the exogenous solution sets.
`ISolutionSetStats`	`getSolutionSetStats(String localName)` Resolve the pre-existing named solution set returning its `ISolutionSetStats`.
`String`	`getSPONamespace()` Return the namespace of the `SPORelation`.
`StaticAnalysisStats`	`getStaticAnalysisStats()` Summary statistics for the static analysis phase.
`long`	`getTimestamp()` The timestamp or transaction identifier associated with the view.
`boolean`	`isCluster()` Return `true` if we are running on a cluster.
`boolean`	`isQuads()` Return `true` iff the target `AbstractTripleStore` is in quads mode.
`boolean`	`isSIDs()` Return `true` iff the target `AbstractTripleStore` is in SIDS mode.
`boolean`	`isTriples()` Return `true` iff the target `AbstractTripleStore` is in triples mode.
`int`	`nextId()` Issue the next bop identifier.
`void`	`setGloballyScopedVariables(Set<IVariable<?>> globallyScopedVariables)` Sets the variables with global scope.
`void`	`setSolutionSetStats(ISolutionSetStats stats)` Set the statistics summary for the exogenous solution sets.
`void`	`setStaticAnalysisStats(StaticAnalysisStats saStats)` Set the statistics object for the static analysis phase.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - astContainer
```
public final ASTContainer astContainer
```
    The ASTContainer and never null.
  - db
```
protected final AbstractTripleStore db
```
    The KB instance.
  - queryEngine
```
public final QueryEngine queryEngine
```
    The QueryEngine.
  - solutionSetManager
```
public final ISolutionSetManager solutionSetManager
```
    The ISolutionSetManager -or- null iff that cache is not enabled.
  - describeCache
```
public final IDescribeCache describeCache
```
    The IDescribeCache -or- null iff that cache is not enabled..
  - queryHints
```
public final Properties queryHints
```
    The query hints from the original #query.
    Note: This acts as a default source for query hints to be applied to the generated AST nodes. In addition, the ASTQueryHintOptimizer uses registered IQueryHint implementations to annotate the original AST as one of the steps when transforming it into the optimized AST. This is done both for the global queryHintss and for magic predicates using the QueryHints.NAMESPACE that appear in the query. Once a query hint is set on an AST node, it will eventually be copied across to PipelineOps generated from that AST node.
    
    See Also:
    QueryHints, QueryHintRegistry, ASTQueryHintOptimizer, Clean up query hints
  - queryId
```
public final UUID queryId
```
    The unique identifier assigned to this query.
    
    See Also:
    QueryHints.QUERYID, QueryEngine.Annotations#QUERY_ID
  - optimizers
```
public final ASTOptimizerList optimizers
```
    The query optimizers (this includes both query rewrites for correct semantics, such as a rewrite of a DESCRIBE query into a CONSTRUCT query, and query rewrites for performance optimizations).
  - context
```
public final BOpContextBase context
```
    Factory for resolving relations and access paths used primarily by AST2BOpJoinss.
  - gpuEvaluation
```
public final IExternalAST2BOp gpuEvaluation
```
    The IExternalAST2BOp for using GPUs or null.
  - nativeDistinctSPO
```
public boolean nativeDistinctSPO
```
    When true, may use the version of DISTINCT which operates on the native heap (this is only used when we are doing a hash join against a default graph access path and the predicate for that access path has a large cardinality).
  - nativeDistinctSPOThreshold
```
public long nativeDistinctSPOThreshold
```
    The threshold at which we will use a native hash set rather than a default hash set for a default graph access path.
  - nativeDistinctSolutions
```
public boolean nativeDistinctSolutions
```
    When true, will use the version of the DISTINCT SOLUTIONS operator which uses the HTree against the native heap.
    
    See Also:
    QueryHints.NATIVE_DISTINCT_SOLUTIONS
  - queryEngineChunkHandler
```
public IChunkHandler queryEngineChunkHandler
```
    Controls whether the intermediate solution chunks on the query engine operator input queues are stored on the native heap and/or the managed object heap.
    
    See Also:
    QueryHints.QUERY_ENGINE_CHUNK_HANDLER, (Vector query engine on native heap)
  - nativeHashJoins
```
public boolean nativeHashJoins
```
    When true, use hash index operations based on the HTree. Otherwise use hash index operations based on the Java collection classes. The HTree is more scalable but has higher overhead for small cardinality hash joins.
    
    See Also:
    QueryHints.NATIVE_HASH_JOINS
  - pipelinedHashJoins
```
public boolean pipelinedHashJoins
```
    When true, use pipelined hash join operations wherever possible. Otherwise use standard, blocking hash joins (which might be more efficient due to less memory overhead). Note that, even if this is set to false, the system chooses pipelined hash joins occasionally for queries with LIMIT.
  - mergeJoin
```
public boolean mergeJoin
```
    When true, a merge-join pattern will be recognized if it appears in a join group. When false, this can still be selectively enabled using a query hint.
    
    See Also:
    QueryHints.MERGE_JOIN
  - maxParallelForSolutionSetHashJoin
```
public int maxParallelForSolutionSetHashJoin
```
    The maximum parallelism for a solution set hash join when the join is used in a context that does permit parallelism, such as sub-group and sub-query evaluation (default ). The historical value for bigdata releases through 1.2.1 was ONE (1). While this join can be evaluated concurrently for multiple input chunks, assessment done with r6411 on BSBM (explore) and govtrack failed to demonstrate any performance advantage when using maxParallel = 5 (the default maximum parallelism as specified by PipelineOp.Annotations#DEFAULT_MAX_PARALLEL. This parameter makes it easier to re-test the effect of parallelism in these joins in the future.
    
    See Also:
    AST2BOpUtility, PipelineOp.Annotations#MAX_PARALLEL, HTreeSolutionSetHashJoinOp, JVMSolutionSetHashJoinOp
  - constructDistinctSPO
```
public boolean constructDistinctSPO
```
    Set by the ConstructDistinctSPOHint. When false, no DISTINCT SPO filter will be imposed by the ASTConstructIterator.
    
    See Also:
    (performance of dumping single graph)
  - remoteAPs
```
public boolean remoteAPs
```
    When true, force the use of REMOTE access paths in scale-out joins.
  - accessPathSampleLimit
```
public int accessPathSampleLimit
```
    The #of samples to take when comparing the cost of a SCAN with an IN filter to as-bound evaluation for each graph in the data set. The samples are taken from the data set. Each sample is a graph (aka context) in the data set. The range counts and estimated cost to visit the AP for each of the sampled contexts are combined to estimate the total cost of visiting all of the contexts in the NG or DG access path.
    When ZERO (0), no cost estimation will be performed and the named graph or default graph join will always use the SCAN + FILTER approach.
  - accessPathScanAndFilter
```
public boolean accessPathScanAndFilter
```
    For named and default graph access paths where access path cost estimation is disabled by setting the accessPathSampleLimit to ZERO (0), this determines whether a SCAN + FILTER or PARALLEL SUBQUERY (aka as-bound data set join) approach.
  - defaultGraphDistinctFilter
```
public boolean defaultGraphDistinctFilter
```
    Whether or not a distinct filter is applied over triples extracted from the default graph (applies in quads mode only). While such a filter in the general case is required for correctness, it might be omitted whenever we know that no triple resides in more than one named graph.
- Constructor Detail
  - AST2BOpContext
```
public AST2BOpContext(ASTContainer astContainer,
              AbstractTripleStore db)
```
    Parameters:
    astContainer - The top-level ASTContainer for the query or update request to be evaluated (required).
    db - The KB instance. TODO We should be passing in the IIndexManager rather than the AbstractTripleStore in order to support cross kb queries. The AST can be annotated with the namespace of the default KB instance, which can then be resolved from the IIndexManager. This would also allow us to clear up the [lex] namespace parameter to the FunctionNode and FunctionRegistry.
- Method Detail
  - getSolutionSetStats
```
public ISolutionSetStats getSolutionSetStats()
```
    Description copied from interface: IEvaluationContext
    
    Some summary statistics about the exogenous solution sets. These are computed by AST2BOpUtility.convert(AST2BOpContext, IBindingSet[]) before it begins to run the IASTOptimizers.
    
    Specified by:
    
    getSolutionSetStats in interface IEvaluationContext
  - getStaticAnalysisStats
```
public StaticAnalysisStats getStaticAnalysisStats()
```
    Description copied from interface: IEvaluationContext
    
    Summary statistics for the static analysis phase.
    
    Specified by:
    
    getStaticAnalysisStats in interface IEvaluationContext
  - setSolutionSetStats
```
public void setSolutionSetStats(ISolutionSetStats stats)
```
    Set the statistics summary for the exogenous solution sets.
    
    Parameters:
    stats - The summary statistics.
    
    Throws:
    
    IllegalArgumentException - if the argument is null
  - setStaticAnalysisStats
```
public void setStaticAnalysisStats(StaticAnalysisStats saStats)
```
    Set the statistics object for the static analysis phase.
    
    Parameters:
    saStats - the static analysis stats object
    
    Throws:
    
    IllegalArgumentException - if the argument is null
  - addQueryAttribute
```
public void addQueryAttribute(Object key,
                     Object val)
```
  - getQueryAttributes
```
public Map<Object,Object> getQueryAttributes()
```
    Return an optional (and immutable) map of key-value pairs that will be attached to the IRunningQuery on the query controller node.
    
    Returns:
    The map -or- null if no query attributes have been declared.
  - getTimestamp
```
public long getTimestamp()
```
    Description copied from interface: IEvaluationContext
    
    The timestamp or transaction identifier associated with the view.
    
    Specified by:
    
    getTimestamp in interface IEvaluationContext
  - nextId
```
public int nextId()
```
    Description copied from interface: IdFactory
    
    Issue the next bop identifier.
    
    Specified by:
    
    nextId in interface IdFactory
  - isCluster
```
public boolean isCluster()
```
    Description copied from interface: IEvaluationContext
    
    Return true if we are running on a cluster.
    
    Specified by:
    
    isCluster in interface IEvaluationContext
  - isQuads
```
public boolean isQuads()
```
    Description copied from interface: IEvaluationContext
    
    Return true iff the target AbstractTripleStore is in quads mode.
    
    Specified by:
    
    isQuads in interface IEvaluationContext
  - isSIDs
```
public boolean isSIDs()
```
    Description copied from interface: IEvaluationContext
    
    Return true iff the target AbstractTripleStore is in SIDS mode.
    
    Specified by:
    
    isSIDs in interface IEvaluationContext
  - isTriples
```
public boolean isTriples()
```
    Description copied from interface: IEvaluationContext
    
    Return true iff the target AbstractTripleStore is in triples mode.
    
    Specified by:
    
    isTriples in interface IEvaluationContext
  - getNamespace
```
public String getNamespace()
```
    Description copied from interface: IEvaluationContext
    
    Return the namespace of the AbstractTripleStore.
    
    Specified by:
    
    getNamespace in interface IEvaluationContext
  - getSPONamespace
```
public String getSPONamespace()
```
    Description copied from interface: IEvaluationContext
    
    Return the namespace of the SPORelation.
    
    Specified by:
    
    getSPONamespace in interface IEvaluationContext
  - getLexiconNamespace
```
public String getLexiconNamespace()
```
    Description copied from interface: IEvaluationContext
    
    Return the namespace of the LexiconRelation.
    
    Specified by:
    
    getLexiconNamespace in interface IEvaluationContext
  - getBOpContext
```
public BOpContextBase getBOpContext()
```
    Description copied from interface: IEvaluationContext
    
    Return the context for evaluation of IValueExpressions during query optimization.
    
    Specified by:
    
    getBOpContext in interface IEvaluationContext
    
    Returns:
    The context that can be used to resolve the ILexiconConfiguration and LexiconRelation for evaluation if IValueExpressions during query optimization. (During query evaluation this information is passed into the pipeline operators by the ContextBindingSet.)
    See Also:
    BLZG-1372
  - createVar
```
public final String createVar(String prefix)
```
    Create a new variable name which is unique within the scope of this AST2BOpContext.
    
    Parameters:
    prefix - The prefix. The general pattern for a prefix is "-foo-".
    
    Returns:
    The unique name.
  - getLexiconReadTimestamp
```
public long getLexiconReadTimestamp()
```
    Description copied from interface: IEvaluationContext
    
    Return the timestamp which will be used to read on the lexicon.
    Note: This uses the timestamp of the triple store view unless this is a read/write transaction, in which case we need to use the last commit point in order to see any writes which it may have performed (lexicon writes are always unisolated).
    
    Specified by:
    
    getLexiconReadTimestamp in interface IEvaluationContext
  - getAbstractTripleStore
```
public AbstractTripleStore getAbstractTripleStore()
```
    Description copied from interface: IEvaluationContext
    
    Return the database.
    
    Specified by:
    
    getAbstractTripleStore in interface IEvaluationContext
  - getSolutionSetManager
```
public ISolutionSetManager getSolutionSetManager()
```
    Description copied from interface: IEvaluationContext
    
    Return the manager for named solution sets (experimental feature).
    
    Specified by:
    
    getSolutionSetManager in interface IEvaluationContext
    
    Returns:
    The manager -or- null.
  - getDescribeCache
```
public IDescribeCache getDescribeCache()
```
    Description copied from interface: IEvaluationContext
    
    Return the cache for described resources (experimental feature).
    
    Specified by:
    
    getDescribeCache in interface IEvaluationContext
    
    Returns:
    The cache -or- null.
    See Also:
    QueryHints.DESCRIBE_CACHE
  - getDescribeMode
```
public DescribeModeEnum getDescribeMode(ProjectionNode projection)
```
    Return the effective DescribeModeEnum.
    
    Parameters:
    projection - The query projection.
    
    Returns:
    The effective DescribeModeEnum
    See Also:
    QueryHints.DESCRIBE_MODE
  - getDescribeIterationLimit
```
public int getDescribeIterationLimit(ProjectionNode projection)
```
    Return the effective iteration limit for a DESCRIBE query.
    
    Parameters:
    projection - The query projection.
    
    Returns:
    The effective iteration limit.
    See Also:
    QueryHints.DESCRIBE_ITERATION_LIMIT
  - getDescribeStatementLimit
```
public int getDescribeStatementLimit(ProjectionNode projection)
```
    Return the effective statement limit for a DESCRIBE query.
    
    Parameters:
    projection - The query projection.
    
    Returns:
    The effective statement limit.
    See Also:
    QueryHints.DESCRIBE_STATEMENT_LIMIT
  - getSolutionSetStats
```
public ISolutionSetStats getSolutionSetStats(String localName)
```
    Description copied from interface: IEvaluationContext
    
    Resolve the pre-existing named solution set returning its ISolutionSetStats.
    
    Specified by:
    
    getSolutionSetStats in interface IEvaluationContext
    
    Returns:
    The ISolutionSetStats
  - getGloballyScopedVariables
```
public Set<IVariable<?>> getGloballyScopedVariables()
```
    Description copied from interface: IEvaluationContext
    
    Returns all the variables with a global scope. This basically serves the purpose of identifying variables that are injected through Sesame's Operation.setBinding() interface. Guaranteed to be not null.
    
    Specified by:
    
    getGloballyScopedVariables in interface IEvaluationContext
    
    Returns:
  - setGloballyScopedVariables
```
public void setGloballyScopedVariables(Set<IVariable<?>> globallyScopedVariables)
```
    Description copied from interface: IEvaluationContext
    
    Sets the variables with global scope. This basically serves the purpose of identifying
    
    Specified by:
    
    setGloballyScopedVariables in interface IEvaluationContext

Class AST2BOpContext

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

astContainer

db

queryEngine

solutionSetManager

describeCache

queryHints

queryId

optimizers

context

gpuEvaluation

nativeDistinctSPO

nativeDistinctSPOThreshold

nativeDistinctSolutions

queryEngineChunkHandler

nativeHashJoins

pipelinedHashJoins

mergeJoin

maxParallelForSolutionSetHashJoin

constructDistinctSPO

remoteAPs

accessPathSampleLimit

accessPathScanAndFilter

defaultGraphDistinctFilter

Constructor Detail

AST2BOpContext

Method Detail

getSolutionSetStats

getStaticAnalysisStats

setSolutionSetStats

setStaticAnalysisStats

addQueryAttribute

getQueryAttributes

getTimestamp

nextId

isCluster

isQuads

isSIDs

isTriples

getNamespace

getSPONamespace

getLexiconNamespace

getBOpContext

createVar

getLexiconReadTimestamp

getAbstractTripleStore

getSolutionSetManager

getDescribeCache

getDescribeMode

getDescribeIterationLimit

getDescribeStatementLimit

getSolutionSetStats

getGloballyScopedVariables

setGloballyScopedVariables