Package org.apache.druid.query.scan

Class ScanQuery

java.lang.Object

org.apache.druid.query.BaseQuery<ScanResultValue>

org.apache.druid.query.scan.ScanQuery

All Implemented Interfaces:

Query<ScanResultValue>

public class ScanQuery
extends BaseQuery<ScanResultValue>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ScanQuery.ResultFormat

Field Summary

Fields

Modifier and Type	Field	Description
static String	CTX_KEY_OUTERMOST	This context flag corresponds to whether the query is running on the "outermost" process (i.e.
static int	DEFAULT_BATCH_SIZE

Fields inherited from class org.apache.druid.query.BaseQuery

QUERY_ID, SQL_QUERY_ID, SUB_QUERY_ID

Fields inherited from interface org.apache.druid.query.Query

DATASOURCE_METADATA, GROUP_BY, SCAN, SEARCH, SEGMENT_METADATA, SELECT, TIME_BOUNDARY, TIMESERIES, TOPN, UNION_QUERY, WINDOW_OPERATOR

Constructor Summary

Constructors

Constructor	Description
ScanQuery(DataSource dataSource, QuerySegmentSpec querySegmentSpec, VirtualColumns virtualColumns, ScanQuery.ResultFormat resultFormat, int batchSize, long scanRowsOffset, long scanRowsLimit, Order orderFromUser, List<OrderBy> orderBysFromUser, DimFilter dimFilter, List<String> columns, Map<String,Object> context, List<ColumnType> columnTypes)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
int	getBatchSize()
List<String>	getColumns()
List<ColumnType>	getColumnTypes()
DimFilter	getFilter()
Integer	getMaxRowsQueuedForOrdering()
Integer	getMaxSegmentPartitionsOrderedInMemory()
OffsetLimit	getOffsetLimit()
List<OrderBy>	getOrderBys()
Set<String>	getRequiredColumns()	Returns the set of columns that this query will need to access out of its datasource.
ScanQuery.ResultFormat	getResultFormat()
com.google.common.collect.Ordering<ScanResultValue>	getResultOrdering()	Default implementation of Query.getResultOrdering() that uses Ordering.natural().
RowSignature	getResultRowSignature(RowSignature.Finalization finalization)
RowSignature	getRowSignature()	Returns the RowSignature.
long	getScanRowsLimit()	Limit for this query; behaves like SQL "LIMIT".
long	getScanRowsOffset()	Offset for this query; behaves like SQL "OFFSET".
Order	getTimeOrder()	If this query is purely-time-ordered, returns a value of the enum Order.
String	getType()
VirtualColumns	getVirtualColumns()
boolean	hasFilters()
int	hashCode()
Boolean	isLegacy()	Deprecated.
boolean	isLimited()	Returns whether this query is limited or not.
String	toString()
static void	verifyOrderByForNativeExecution(ScanQuery query)	Verifies that the ordering of a query is solely determined by getTimeOrder().
ScanQuery	withDataSource(DataSource dataSource)
ScanQuery	withLimit(long newLimit)
ScanQuery	withOffset(long newOffset)
ScanQuery	withOverriddenContext(Map<String,Object> contextOverrides)
ScanQuery	withQuerySegmentSpec(QuerySegmentSpec querySegmentSpec)	Returns a new query, identical to this one, but with a different associated QuerySegmentSpec.

Methods inherited from class org.apache.druid.query.BaseQuery

checkInterrupted, computeOverriddenContext, computeOverridenContext, context, getContext, getDataSource, getDuration, getGranularity, getId, getIntervals, getQuerySegmentSpec, getQuerySegmentSpecForLookUp, getRunner, getSubQueryId, getTimezone, withId, withSqlQueryId, withSubQueryId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.druid.query.Query

getContextBoolean, getContextHumanReadableBytes, getContextValue, getDataSourceAnalysis, getMostSpecificId, getResultRowSignature, getSingleInterval, getSqlQueryId, optimizeForSegment, withDefaultSubQueryId, withLane, withPriority

Field Detail

CTX_KEY_OUTERMOST

public static final String CTX_KEY_OUTERMOST

This context flag corresponds to whether the query is running on the "outermost" process (i.e. the process the query is sent to).

See Also:

Constant Field Values

DEFAULT_BATCH_SIZE

public static final int DEFAULT_BATCH_SIZE

See Also:

Constant Field Values

Constructor Detail

ScanQuery

public ScanQuery(DataSource dataSource,
                 QuerySegmentSpec querySegmentSpec,
                 VirtualColumns virtualColumns,
                 ScanQuery.ResultFormat resultFormat,
                 int batchSize,
                 long scanRowsOffset,
                 long scanRowsLimit,
                 Order orderFromUser,
                 List<OrderBy> orderBysFromUser,
                 DimFilter dimFilter,
                 List<String> columns,
                 Map<String,Object> context,
                 List<ColumnType> columnTypes)

Method Detail

verifyOrderByForNativeExecution

public static void verifyOrderByForNativeExecution(ScanQuery query)

Verifies that the ordering of a query is solely determined by getTimeOrder(). Required to actually execute queries, because getOrderBys() is not yet understood by the query engines.

Throws:

IllegalStateException - if the ordering is not solely determined by getTimeOrder()

getVirtualColumns

public VirtualColumns getVirtualColumns()

getResultFormat

public ScanQuery.ResultFormat getResultFormat()

getBatchSize

public int getBatchSize()

getScanRowsOffset

public long getScanRowsOffset()

Offset for this query; behaves like SQL "OFFSET". Zero means no offset. Negative values are invalid.

getScanRowsLimit

public long getScanRowsLimit()

Limit for this query; behaves like SQL "LIMIT". Will always be positive. Long.MAX_VALUE is used in situations where the user wants an effectively unlimited result set.

getOffsetLimit

public OffsetLimit getOffsetLimit()

isLimited

public boolean isLimited()

Returns whether this query is limited or not. Because Long.MAX_VALUE is used to signify unlimitedness, this is equivalent to getScanRowsLimit() != Long.Max_VALUE.

See Also:

getScanRowsLimit()

getTimeOrder

public Order getTimeOrder()

If this query is purely-time-ordered, returns a value of the enum Order. Otherwise, returns Order.NONE. If the returned value is Order.NONE it may not agree with getOrderBys().

getOrderBys

public List<OrderBy> getOrderBys()

getMaxRowsQueuedForOrdering

@Nullable
public Integer getMaxRowsQueuedForOrdering()

getMaxSegmentPartitionsOrderedInMemory

@Nullable
public Integer getMaxSegmentPartitionsOrderedInMemory()

hasFilters

public boolean hasFilters()

getFilter

@Nullable
public DimFilter getFilter()

getType

public String getType()

getColumns

@Nullable
public List<String> getColumns()

getColumnTypes

@Nullable
public List<ColumnType> getColumnTypes()

isLegacy

@Deprecated
public Boolean isLegacy()

Deprecated.

Prior to PR https://github.com/apache/druid/pull/16659 (Druid 31) data servers require the "legacy" parameter to be set to a non-null value. For compatibility with older data servers during rolling updates, we need to write out "false".

getResultOrdering

public com.google.common.collect.Ordering<ScanResultValue> getResultOrdering()

Description copied from class: BaseQuery

Default implementation of Query.getResultOrdering() that uses Ordering.natural(). If your query result type T is not Comparable, you must override this method.

Specified by:

getResultOrdering in interface Query<ScanResultValue>

Overrides:

getResultOrdering in class BaseQuery<ScanResultValue>

getRequiredColumns

@Nullable
public Set<String> getRequiredColumns()

Description copied from interface: Query

Returns the set of columns that this query will need to access out of its datasource.

This method does not "look into" what the datasource itself is doing. For example, if a query is built on a QueryDataSource, this method will not return the columns used by that subquery. As another example, if a query is built on a JoinDataSource, this method will not return the columns from the underlying datasources that are used by the join condition, unless those columns are also used by this query in other ways.

Returns null if the set of required columns cannot be known ahead of time.

withOffset

public ScanQuery withOffset(long newOffset)

withLimit

public ScanQuery withLimit(long newLimit)

withQuerySegmentSpec

public ScanQuery withQuerySegmentSpec(QuerySegmentSpec querySegmentSpec)

Description copied from interface: Query

Returns a new query, identical to this one, but with a different associated QuerySegmentSpec.

This often changes the behavior of Query.getRunner(QuerySegmentWalker), since most queries inherit that method from BaseQuery, which implements it by calling QuerySegmentSpec.lookup(org.apache.druid.query.Query<T>, org.apache.druid.query.QuerySegmentWalker).

withDataSource

public ScanQuery withDataSource(DataSource dataSource)

withOverriddenContext

public ScanQuery withOverriddenContext(Map<String,Object> contextOverrides)

equals

public boolean equals(Object o)

Overrides:

equals in class BaseQuery<ScanResultValue>

hashCode

public int hashCode()

Overrides:

hashCode in class BaseQuery<ScanResultValue>

toString

public String toString()

Overrides:

toString in class Object

getResultRowSignature

public RowSignature getResultRowSignature(RowSignature.Finalization finalization)

getRowSignature

@Nullable
public RowSignature getRowSignature()

Returns the RowSignature. If columnTypes is not available it will do its best to fill in the types.