org.apache.cassandra.db

Class SinglePartitionReadCommand

java.lang.Object

org.apache.cassandra.db.monitoring.MonitorableImpl

org.apache.cassandra.db.ReadCommand

org.apache.cassandra.db.SinglePartitionReadCommand

All Implemented Interfaces:

Monitorable, ReadQuery, SinglePartitionReadQuery

public class SinglePartitionReadCommand
extends ReadCommand
implements SinglePartitionReadQuery

A read command that selects a (part of a) single partition.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SinglePartitionReadCommand.Group Groups multiple single partition read commands.

Nested classes/interfaces inherited from class org.apache.cassandra.db.ReadCommand

ReadCommand.CheckForAbort, ReadCommand.Kind, ReadCommand.SelectionDeserializer, ReadCommand.Serializer

Field Summary

Fields

Modifier and Type	Field and Description
protected static ReadCommand.SelectionDeserializer	selectionDeserializer

Fields inherited from class org.apache.cassandra.db.ReadCommand

logger, serializer

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SinglePartitionReadCommand(boolean isDigest, int digestVersion, boolean acceptsTransient, TableMetadata metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits, DecoratedKey partitionKey, ClusteringIndexFilter clusteringIndexFilter, IndexMetadata index)

Method Summary

Modifier and Type	Method and Description
protected void	appendCQLWhereClause(java.lang.StringBuilder sb)
ClusteringIndexFilter	clusteringIndexFilter()
ClusteringIndexFilter	clusteringIndexFilter(DecoratedKey key) The clustering index filter this command to use for the provided key.
ColumnFilter	columnFilter() A filter on which (non-PK) columns must be returned by the query.
SinglePartitionReadCommand	copy() Returns a copy of this command.
protected SinglePartitionReadCommand	copyAsDigestQuery()
protected SinglePartitionReadCommand	copyAsTransientQuery()
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, java.nio.ByteBuffer key, Slices slices) Creates a new single partition slice command for the provided slices.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits, DecoratedKey partitionKey, ClusteringIndexFilter clusteringIndexFilter) Creates a new read command on a single partition.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, ColumnFilter columnFilter, RowFilter rowFilter, DataLimits limits, DecoratedKey partitionKey, ClusteringIndexFilter clusteringIndexFilter, IndexMetadata indexMetadata) Creates a new read command on a single partition.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, DecoratedKey key, Clustering<?> name) Creates a new single partition name command for the provided row.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, DecoratedKey key, ColumnFilter columnFilter, ClusteringIndexFilter filter) Creates a new read command on a single partition.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, DecoratedKey key, java.util.NavigableSet<Clustering<?>> names) Creates a new single partition name command for the provided rows.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, DecoratedKey key, Slice slice) Creates a new single partition slice command for the provided single slice.
static SinglePartitionReadCommand	create(TableMetadata metadata, int nowInSec, DecoratedKey key, Slices slices) Creates a new single partition slice command for the provided slices.
PartitionIterator	execute(ConsistencyLevel consistency, ClientState clientState, long queryStartNanoTime) Executes the query at the provided consistency level.
PartitionIterator	executeInternal(ReadExecutionController controller) Execute the query for internal queries (that is, it basically executes the query locally).
SinglePartitionReadCommand	forPaging(Clustering<?> lastReturned, DataLimits limits) Returns a new SinglePartitionReadQuery suitable to paging from the last returned row.
static SinglePartitionReadCommand	fullPartitionRead(TableMetadata metadata, int nowInSec, java.nio.ByteBuffer key) Creates a new read command that queries a single partition in its entirety.
static SinglePartitionReadCommand	fullPartitionRead(TableMetadata metadata, int nowInSec, DecoratedKey key) Creates a new read command that queries a single partition in its entirety.
long	getTimeout(java.util.concurrent.TimeUnit unit) The configured timeout for this command.
boolean	isLimitedToOnePartition()
boolean	isRangeRequest()
boolean	isReversed() Whether the underlying ClusteringIndexFilter is reversed or not.
DataLimits	limits() The limits for the query.
TableMetadata	metadata() The metadata for the table this is a query on.
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
UnfilteredRowIterator	queryMemtableAndDisk(ColumnFamilyStore cfs, ReadExecutionController executionController) Queries both memtable and sstables to fetch the result of this query.
protected UnfilteredPartitionIterator	queryStorage(ColumnFamilyStore cfs, ReadExecutionController executionController)
protected void	recordLatency(TableMetrics metric, long latencyNanos)
RowFilter	rowFilter() Filters/Resrictions on CQL rows.
protected long	selectionSerializedSize(int version)
boolean	selectsFullPartition() Checks if this ReadQuery selects full partitions, that is it has no filtering on clustering or regular columns.
protected void	serializeSelection(DataOutputPlus out, int version)
java.lang.String	toString()
Verb	verb()
SinglePartitionReadCommand	withUpdatedLimit(DataLimits newLimits) Creates a new ReadCommand instance with new limits.

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

acceptsTransient, copyAsDigestQuery, copyAsDigestQuery, copyAsTransientQuery, copyAsTransientQuery, createMessage, createResponse, digestVersion, executeLocally, executionController, getIndex, getRepairedDataDigest, indexMetadata, isDigestQuery, isRepairedDataDigestConclusive, isTrackingRepairedStatus, maybeValidateIndex, name, oldestUnrepairedTombstone, setDigestVersion, toCQLString, trackRepairedStatus, withoutPurgeableTombstones, withStateTracking

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, wait, wait, wait

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

createGroup, getPager, selectsClustering, selectsKey

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

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

Field Detail

selectionDeserializer

protected static final ReadCommand.SelectionDeserializer selectionDeserializer

Constructor Detail

SinglePartitionReadCommand

protected SinglePartitionReadCommand(boolean isDigest,
                                     int digestVersion,
                                     boolean acceptsTransient,
                                     TableMetadata metadata,
                                     int nowInSec,
                                     ColumnFilter columnFilter,
                                     RowFilter rowFilter,
                                     DataLimits limits,
                                     DecoratedKey partitionKey,
                                     ClusteringIndexFilter clusteringIndexFilter,
                                     IndexMetadata index)

Method Detail

create

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

Creates a new read command on a single partition.

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.

indexMetadata - explicitly specified index to use for the query

Returns:

a newly created read command.

create

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

Creates a new read command 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 command.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                DecoratedKey key,
                                                ColumnFilter columnFilter,
                                                ClusteringIndexFilter filter)

Creates a new read command 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.

key - the partition key for the partition to query.

columnFilter - the column filter to use for the query.

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

Returns:

a newly created read command. The returned command will use no row filter and have no limits.

fullPartitionRead

public static SinglePartitionReadCommand fullPartitionRead(TableMetadata metadata,
                                                           int nowInSec,
                                                           DecoratedKey key)

Creates a new read command that queries a single partition in its entirety.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

Returns:

a newly created read command that queries all the rows of key.

fullPartitionRead

public static SinglePartitionReadCommand fullPartitionRead(TableMetadata metadata,
                                                           int nowInSec,
                                                           java.nio.ByteBuffer key)

Creates a new read command that queries a single partition in its entirety.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

Returns:

a newly created read command that queries all the rows of key.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                DecoratedKey key,
                                                Slice slice)

Creates a new single partition slice command for the provided single slice.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

slice - the slice of rows to query.

Returns:

a newly created read command that queries slice in key. The returned query will query every columns for the table (without limit or row filtering) and be in forward order.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                DecoratedKey key,
                                                Slices slices)

Creates a new single partition slice command for the provided slices.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

slices - the slices of rows to query.

Returns:

a newly created read command that queries the slices in key. The returned query will query every columns for the table (without limit or row filtering) and be in forward order.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                java.nio.ByteBuffer key,
                                                Slices slices)

Creates a new single partition slice command for the provided slices.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

slices - the slices of rows to query.

Returns:

a newly created read command that queries the slices in key. The returned query will query every columns for the table (without limit or row filtering) and be in forward order.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                DecoratedKey key,
                                                java.util.NavigableSet<Clustering<?>> names)

Creates a new single partition name command for the provided rows.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

names - the clustering for the rows to query.

Returns:

a newly created read command that queries the names in key. The returned query will query every columns (without limit or row filtering) and be in forward order.

create

public static SinglePartitionReadCommand create(TableMetadata metadata,
                                                int nowInSec,
                                                DecoratedKey key,
                                                Clustering<?> name)

Creates a new single partition name command for the provided row.

Parameters:

metadata - the table to query.

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

key - the partition key for the partition to query.

name - the clustering for the row to query.

Returns:

a newly created read command that queries name in key. The returned query will query every columns (without limit or row filtering).

copy

public SinglePartitionReadCommand copy()

Description copied from class: ReadCommand

Returns a copy of this command.

Specified by:

copy in class ReadCommand

Returns:

a copy of this command.

copyAsDigestQuery

protected SinglePartitionReadCommand copyAsDigestQuery()

Specified by:

copyAsDigestQuery in class ReadCommand

copyAsTransientQuery

protected SinglePartitionReadCommand copyAsTransientQuery()

Specified by:

copyAsTransientQuery in class ReadCommand

withUpdatedLimit

public SinglePartitionReadCommand withUpdatedLimit(DataLimits newLimits)

Description copied from class: ReadCommand

Creates a new ReadCommand instance with new limits.

Specified by:

withUpdatedLimit in interface SinglePartitionReadQuery

Specified by:

withUpdatedLimit in class ReadCommand

Parameters:

newLimits - the new limits

Returns:

a new ReadCommand with the updated limits

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

clusteringIndexFilter

public ClusteringIndexFilter clusteringIndexFilter()

Specified by:

clusteringIndexFilter in interface SinglePartitionReadQuery

clusteringIndexFilter

public ClusteringIndexFilter clusteringIndexFilter(DecoratedKey key)

Description copied from class: ReadCommand

The clustering index filter this command to use for the provided key.

Note that that method should only be called on a key actually queried by this command and in practice, this will almost always return the same filter, but for the sake of paging, the filter on the first key of a range command might be slightly different.

Specified by:

clusteringIndexFilter in class ReadCommand

Parameters:

key - a partition key queried by this command.

Returns:

the ClusteringIndexFilter to use for the partition of key key.

getTimeout

public long getTimeout(java.util.concurrent.TimeUnit unit)

Description copied from class: ReadCommand

The configured timeout for this command.

Specified by:

getTimeout in class ReadCommand

Returns:

the configured timeout for this command.

isReversed

public boolean isReversed()

Description copied from class: ReadCommand

Whether the underlying ClusteringIndexFilter is reversed or not.

Specified by:

isReversed in class ReadCommand

Returns:

whether the underlying ClusteringIndexFilter is reversed or not.

forPaging

public SinglePartitionReadCommand 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.

execute

public PartitionIterator execute(ConsistencyLevel consistency,
                                 ClientState clientState,
                                 long queryStartNanoTime)
                          throws RequestExecutionException

Description copied from interface: ReadQuery

Executes the query at the provided consistency level.

Specified by:

execute in interface ReadQuery

Parameters:

consistency - the consistency level to achieve for the query.

clientState - the ClientState for the query. In practice, this can be null unless consistency is a serial consistency.

Returns:

the result of the query.

Throws:

RequestExecutionException

recordLatency

protected void recordLatency(TableMetrics metric,
                             long latencyNanos)

Specified by:

recordLatency in class ReadCommand

queryStorage

protected UnfilteredPartitionIterator queryStorage(ColumnFamilyStore cfs,
                                                   ReadExecutionController executionController)

Specified by:

queryStorage in class ReadCommand

queryMemtableAndDisk

public UnfilteredRowIterator queryMemtableAndDisk(ColumnFamilyStore cfs,
                                                  ReadExecutionController executionController)

Queries both memtable and sstables to fetch the result of this query.

Please note that this method: 1) does not check the row cache. 2) does not apply the query limit, nor the row filter (and so ignore 2ndary indexes). Those are applied in ReadCommand.executeLocally(org.apache.cassandra.db.ReadExecutionController). 3) does not record some of the read metrics (latency, scanned cells histograms) nor throws TombstoneOverwhelmingException. It is publicly exposed because there is a few places where that is exactly what we want, but it should be used only where you know you don't need thoses things.

Also note that one must have created a ReadExecutionController on the queried table and we require it as a parameter to enforce that fact, even though it's not explicitlly used by the method.

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.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

verb

public Verb verb()

Specified by:

verb in class ReadCommand

appendCQLWhereClause

protected void appendCQLWhereClause(java.lang.StringBuilder sb)

Specified by:

appendCQLWhereClause in class ReadCommand

serializeSelection

protected void serializeSelection(DataOutputPlus out,
                                  int version)
                           throws java.io.IOException

Specified by:

serializeSelection in class ReadCommand

Throws:

java.io.IOException

selectionSerializedSize

protected long selectionSerializedSize(int version)

Specified by:

selectionSerializedSize in class ReadCommand

isLimitedToOnePartition

public boolean isLimitedToOnePartition()

Specified by:

isLimitedToOnePartition in class ReadCommand

isRangeRequest

public boolean isRangeRequest()

Specified by:

isRangeRequest in class ReadCommand

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.

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.