org.apache.cassandra.db

Class VirtualTableSinglePartitionReadQuery

java.lang.Object

org.apache.cassandra.db.monitoring.MonitorableImpl

org.apache.cassandra.db.VirtualTableReadQuery

org.apache.cassandra.db.VirtualTableSinglePartitionReadQuery

All Implemented Interfaces:

Monitorable, ReadQuery, SinglePartitionReadQuery

public class VirtualTableSinglePartitionReadQuery
extends VirtualTableReadQuery
implements SinglePartitionReadQuery

A read query that selects a (part of a) single partition of a virtual table.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	VirtualTableSinglePartitionReadQuery.Group Groups multiple single partition read queries.

Method Summary

Modifier and Type	Method and Description
protected void	appendCQLWhereClause(java.lang.StringBuilder sb)
ClusteringIndexFilter	clusteringIndexFilter()
ColumnFilter	columnFilter() A filter on which (non-PK) columns must be returned by the query.
static VirtualTableSinglePartitionReadQuery	create(TableMetadata metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits, DecoratedKey partitionKey, ClusteringIndexFilter clusteringIndexFilter) Creates a new read query on a single partition.
PartitionIterator	executeInternal(ReadExecutionController controller) Execute the query for internal queries (that is, it basically executes the query locally).
SinglePartitionReadQuery	forPaging(Clustering<?> lastReturned, DataLimits limits) Returns a new SinglePartitionReadQuery suitable to paging from the last returned row.
DataLimits	limits() The limits for the query.
TableMetadata	metadata() The metadata for the table this is a query on.
java.lang.String	name()
int	nowInSec() The time in seconds to use as "now" for this query.
DecoratedKey	partitionKey() Returns the key of the partition queried by this ReadQuery
protected UnfilteredPartitionIterator	queryVirtualTable()
RowFilter	rowFilter() Filters/Resrictions on CQL rows.
boolean	selectsFullPartition() Checks if this ReadQuery selects full partitions, that is it has no filtering on clustering or regular columns.
java.lang.String	toCQLString() Recreate the CQL string corresponding to this query.
SinglePartitionReadQuery	withUpdatedLimit(DataLimits newLimits) Creates a new SinglePartitionReadQuery with the specified limits.

Methods inherited from class org.apache.cassandra.db.VirtualTableReadQuery

execute, executeLocally, executionController

Methods inherited from class org.apache.cassandra.db.monitoring.MonitorableImpl

abort, complete, creationTimeNanos, isAborted, isCompleted, isCrossNode, isInProgress, isSlow, setMonitoringTime, slowTimeoutNanos, timeoutNanos

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.db.SinglePartitionReadQuery

create, createGroup, getPager, selectsClustering, selectsKey

Methods inherited from interface org.apache.cassandra.db.ReadQuery

columnFilter, empty, execute, executeInternal, executeLocally, executionController, isEmpty, limits, maybeValidateIndex, metadata, nowInSec, rowFilter

Method Detail

create

public static VirtualTableSinglePartitionReadQuery create(TableMetadata metadata,
                                                          int nowInSec,
                                                          ColumnFilter columnFilter,
                                                          RowFilter rowFilter,
                                                          DataLimits limits,
                                                          DecoratedKey partitionKey,
                                                          ClusteringIndexFilter clusteringIndexFilter)

Description copied from interface: SinglePartitionReadQuery

Creates a new read query on a single partition.

Specified by:

create in interface SinglePartitionReadQuery

Parameters:

metadata - the table to query.

nowInSec - the time in seconds to use are "now" for this query.

columnFilter - the column filter to use for the query.

rowFilter - the row filter to use for the query.

limits - the limits to use for the query.

partitionKey - the partition key for the partition to query.

clusteringIndexFilter - the clustering index filter to use for the query.

Returns:

a newly created read query.

appendCQLWhereClause

protected void appendCQLWhereClause(java.lang.StringBuilder sb)

clusteringIndexFilter

public ClusteringIndexFilter clusteringIndexFilter()

Specified by:

clusteringIndexFilter in interface SinglePartitionReadQuery

selectsFullPartition

public boolean selectsFullPartition()

Description copied from interface: ReadQuery

Checks if this ReadQuery selects full partitions, that is it has no filtering on clustering or regular columns.

Specified by:

selectsFullPartition in interface ReadQuery

Returns:

true if this ReadQuery selects full partitions, false otherwise.

partitionKey

public DecoratedKey partitionKey()

Description copied from interface: SinglePartitionReadQuery

Returns the key of the partition queried by this ReadQuery

Specified by:

partitionKey in interface SinglePartitionReadQuery

Returns:

the key of the partition queried

withUpdatedLimit

public SinglePartitionReadQuery withUpdatedLimit(DataLimits newLimits)

Description copied from interface: SinglePartitionReadQuery

Creates a new SinglePartitionReadQuery with the specified limits.

Specified by:

withUpdatedLimit in interface SinglePartitionReadQuery

Parameters:

newLimits - the new limits

Returns:

the new SinglePartitionReadQuery

forPaging

public SinglePartitionReadQuery forPaging(Clustering<?> lastReturned,
                                          DataLimits limits)

Description copied from interface: SinglePartitionReadQuery

Returns a new SinglePartitionReadQuery suitable to paging from the last returned row.

Specified by:

forPaging in interface SinglePartitionReadQuery

Parameters:

lastReturned - the last row returned by the previous page. The newly created query will only query row that comes after this (in query order). This can be null if this is the first page.

limits - the limits to use for the page to query.

Returns:

the newly create query.

queryVirtualTable

protected UnfilteredPartitionIterator queryVirtualTable()

Specified by:

queryVirtualTable in class VirtualTableReadQuery

metadata

public TableMetadata metadata()

Description copied from interface: ReadQuery

The metadata for the table this is a query on.

Specified by:

metadata in interface ReadQuery

Returns:

the metadata for the table this is a query on.

name

public java.lang.String name()

Specified by:

name in interface Monitorable

executeInternal

public PartitionIterator executeInternal(ReadExecutionController controller)

Description copied from interface: ReadQuery

Execute the query for internal queries (that is, it basically executes the query locally).

Specified by:

executeInternal in interface ReadQuery

Parameters:

controller - the ReadExecutionController protecting the read.

Returns:

the result of the query.

limits

public DataLimits limits()

Description copied from interface: ReadQuery

The limits for the query.

Specified by:

limits in interface ReadQuery

Returns:

The limits for the query.

nowInSec

public int nowInSec()

Description copied from interface: ReadQuery

The time in seconds to use as "now" for this query.

We use the same time as "now" for the whole query to avoid considering different values as expired during the query, which would be buggy (would throw of counting amongst other things).

Specified by:

nowInSec in interface ReadQuery

Returns:

the time (in seconds) to use as "now".

rowFilter

public RowFilter rowFilter()

Description copied from interface: ReadQuery

Filters/Resrictions on CQL rows.

This contains the restrictions that are not directly handled by the ClusteringIndexFilter. More specifically, this includes any non-PK column restrictions and can include some PK columns restrictions when those can't be satisfied entirely by the clustering index filter (because not all clustering columns have been restricted for instance). If there is 2ndary indexes on the table, one of this restriction might be handled by a 2ndary index.

Specified by:

rowFilter in interface ReadQuery

Returns:

the filter holding the expression that rows must satisfy.

columnFilter

public ColumnFilter columnFilter()

Description copied from interface: ReadQuery

A filter on which (non-PK) columns must be returned by the query.

Specified by:

columnFilter in interface ReadQuery

Returns:

which columns must be fetched by this query.

toCQLString

public java.lang.String toCQLString()

Recreate the CQL string corresponding to this query.

Note that in general the returned string will not be exactly the original user string, first because there isn't always a single syntax for a given query, but also because we don't have all the information needed (we know the non-PK columns queried but not the PK ones as internally we query them all). So this shouldn't be relied too strongly, but this should be good enough for debugging purpose which is what this is for.