Package org.elasticsearch.xpack.esql.io.stream

Class PlanStreamOutput

java.lang.Object

java.io.OutputStream

org.elasticsearch.common.io.stream.StreamOutput

org.elasticsearch.xpack.esql.io.stream.PlanStreamOutput

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public final class PlanStreamOutput
extends StreamOutput

A customized stream output used to serialize ESQL physical plan fragments. Complements stream output with methods that write plan nodes, Attributes, Expressions, etc.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<Attribute,Integer>	cachedAttributes	Cache for field attributes.
protected final Map<EsField,Integer>	cachedEsFields	Cache for EsFields.
protected static final int	MAX_SERIALIZED_ATTRIBUTES	max number of attributes that can be cached for serialization
protected final Map<String,Integer>	stringCache

Fields inherited from class org.elasticsearch.common.io.stream.StreamOutput

GENERIC_LIST_HEADER

Constructor Summary

Constructors

Constructor	Description
PlanStreamOutput(StreamOutput delegate, Configuration configuration)
PlanStreamOutput(StreamOutput delegate, Configuration configuration, int maxSerializedAttributes)

Method Summary

Modifier and Type	Method	Description
void	close()
void	flush()
TransportVersion	getTransportVersion()
long	position()
void	setTransportVersion(TransportVersion version)
boolean	writeAttributeCacheHeader(Attribute attribute)	Writes a cache header for an Attribute and caches it if it is not already in the cache.
void	writeByte(byte b)
void	writeBytes(byte[] b, int offset, int length)
void	writeCachedBlock(Block block)	Write a Block as part of the plan.
void	writeCachedString(String string)	Writes a string caching it, ie.
boolean	writeEsFieldCacheHeader(EsField field, TransportVersion transportVersion)	Writes a cache header for an EsField and caches it if it is not already in the cache.
void	writeGenericString(String value)
void	writeOptionalCachedString(String str)
void	writeOptionalString(String str)
void	writeString(String str)

Methods inherited from class org.elasticsearch.common.io.stream.StreamOutput

checkWriteable, legacyWriteWithSizePrefix, write, write, writeArray, writeArray, writeBigInteger, writeBoolean, writeByteArray, writeBytes, writeBytes, writeBytesRef, writeBytesReference, writeCollection, writeCollection, writeDouble, writeDoubleArray, writeDoubleLE, writeEnum, writeEnumSet, writeException, writeFloat, writeFloatArray, writeGenericList, writeGenericMap, writeGenericNull, writeGenericValue, writeGeoPoint, writeInstant, writeInt, writeIntArray, writeIntLE, writeLong, writeLongArray, writeLongLE, writeMap, writeMap, writeMap, writeMapValues, writeMapValues, writeMapWithConsistentOrder, writeMissingString, writeMissingWriteable, writeNamedWriteable, writeNamedWriteableCollection, writeOptional, writeOptionalArray, writeOptionalArray, writeOptionalBoolean, writeOptionalByteArray, writeOptionalBytesReference, writeOptionalCollection, writeOptionalCollection, writeOptionalDouble, writeOptionalEnum, writeOptionalException, writeOptionalFloat, writeOptionalFloatArray, writeOptionalInstant, writeOptionalInt, writeOptionalLong, writeOptionalMap, writeOptionalNamedWriteable, writeOptionalNamedWriteableCollection, writeOptionalSecureString, writeOptionalStringArray, writeOptionalStringCollection, writeOptionalText, writeOptionalTimeValue, writeOptionalVInt, writeOptionalVLong, writeOptionalWriteable, writeOptionalZoneId, writeSecureString, writeShort, writeStringArray, writeStringArrayNullable, writeStringCollection, writeText, writeTimeValue, writeVInt, writeVIntArray, writeVLong, writeVLongArray, writeWithSizePrefix, writeWriteable, writeZLong, writeZoneId

Methods inherited from class java.io.OutputStream

nullOutputStream, write

Methods inherited from class java.lang.Object

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

Field Details

MAX_SERIALIZED_ATTRIBUTES

protected static final int MAX_SERIALIZED_ATTRIBUTES

max number of attributes that can be cached for serialization

TODO should this be a cluster setting...?

See Also:

• Constant Field Values

cachedAttributes

protected final Map<Attribute,Integer> cachedAttributes

Cache for field attributes. Field attributes can be a significant part of the query execution plan, especially for queries like `from *`, that can have thousands of output columns. Attributes can be shared by many plan nodes (eg. ExcahngeSink output, Project output, EsRelation fields); in addition, multiple Attributes can share the same parent field. This cache allows to send each attribute only once; from the second occurrence, only an id will be sent

cachedEsFields

protected final Map<EsField,Integer> cachedEsFields

Cache for EsFields.

stringCache

protected final Map<String,Integer> stringCache

Constructor Details

PlanStreamOutput

public PlanStreamOutput(StreamOutput delegate,
 @Nullable
 Configuration configuration)
                 throws IOException

Throws:

IOException

PlanStreamOutput

public PlanStreamOutput(StreamOutput delegate,
 @Nullable
 Configuration configuration,
 int maxSerializedAttributes)
                 throws IOException

Throws:

IOException

Method Details

writeByte

public void writeByte(byte b)
               throws IOException

Specified by:

writeByte in class StreamOutput

Throws:

IOException

writeBytes

public void writeBytes(byte[] b,
 int offset,
 int length)
                throws IOException

Specified by:

writeBytes in class StreamOutput

Throws:

IOException

position

public long position()

Specified by:

position in class StreamOutput

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Specified by:

flush in class StreamOutput

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class StreamOutput

Throws:

IOException

getTransportVersion

public TransportVersion getTransportVersion()

Overrides:

getTransportVersion in class StreamOutput

setTransportVersion

public void setTransportVersion(TransportVersion version)

Overrides:

setTransportVersion in class StreamOutput

writeCachedBlock

public void writeCachedBlock(Block block)
                      throws IOException

Write a Block as part of the plan.

These Blocks are not tracked by BlockFactory and closing them does nothing so they should be small. We do make sure not to send duplicates, reusing blocks sent as part of the Configuration.tables() if possible, otherwise sending a Block inline.

Throws:

IOException

writeAttributeCacheHeader

public boolean writeAttributeCacheHeader(Attribute attribute)
                                  throws IOException

Writes a cache header for an Attribute and caches it if it is not already in the cache. In that case, the attribute will have to serialize itself into this stream immediately after this method call.

Parameters:

attribute - The attribute to serialize

Returns:

true if the attribute needs to serialize itself, false otherwise (ie. if already cached)

Throws:

IOException

writeEsFieldCacheHeader

public boolean writeEsFieldCacheHeader(EsField field,
 TransportVersion transportVersion)
                                throws IOException

Writes a cache header for an EsField and caches it if it is not already in the cache. In that case, the field will have to serialize itself into this stream immediately after this method call.

Parameters:

field - The EsField to serialize

transportVersion - The transport version to use for serialization, needed to get the correct field name in case of versioned fields.

Returns:

true if the attribute needs to serialize itself, false otherwise (ie. if already cached)

Throws:

IOException

writeString

public void writeString(String str)
                 throws IOException

Specified by:

writeString in class StreamOutput

Throws:

IOException

writeOptionalString

public void writeOptionalString(@Nullable
 String str)
                         throws IOException

Specified by:

writeOptionalString in class StreamOutput

Throws:

IOException

writeGenericString

public void writeGenericString(String value)
                        throws IOException

Specified by:

writeGenericString in class StreamOutput

Throws:

IOException

writeCachedString

public void writeCachedString(String string)
                       throws IOException

Writes a string caching it, ie. the second time the same string is written, only a small, numeric ID will be sent. This should be used only to serialize recurring strings. Values serialized with this method have to be deserialized with PlanStreamInput.readCachedString()

Throws:

IOException

writeOptionalCachedString

public void writeOptionalCachedString(String str)
                               throws IOException

Throws:

IOException