Interface QuerySplitter (2.20.0)

Version 2.20.0

• 2.24.3 (latest)
• 2.24.1
• 2.23.0
• 2.22.0
• 2.21.3
• 2.20.2
• 2.19.2
• 2.18.5
• 2.17.6

public interface QuerySplitter

Provides the ability to split a query into multiple shards.

Methods

getSplits(Query query, PartitionId partition, int numSplits, Datastore datastore)

public abstract List<Query> getSplits(Query query, PartitionId partition, int numSplits, Datastore datastore)

Returns a list of sharded Querys for the given query.

This will create up to the desired number of splits, however it may return less splits if the desired number of splits is unavailable. This will happen if the number of split points provided by the underlying Datastore is less than the desired number, which will occur if the number of results for the query is too small.

Parameters
Name	Description
query	Query the query to split.
partition	PartitionId the partition the query is running in.
numSplits	int the desired number of splits.
datastore	Datastore the datastore to run on.

Returns
Type	Description
List<Query>

Exceptions
Type	Description
DatastoreException	if there was a datastore error while generating query splits.

getSplits(Query query, PartitionId partition, int numSplits, Datastore datastore, Timestamp readTime)

public default List<Query> getSplits(Query query, PartitionId partition, int numSplits, Datastore datastore, Timestamp readTime)

Beta

This feature is covered by the Pre-GA Offerings Terms of the Terms of Service. Pre-GA libraries might have limited support, and changes to pre-GA libraries might not be compatible with other pre-GA versions. For more information, see the launch stage descriptions.

Same as #getSplits(Query, PartitionId, int, Datastore) but the splits are based on readTime, and the returned sharded Querys should also be executed with readTime. Reading from a timestamp is currently a private preview feature in Datastore.

Parameters
Name	Description
query	Query
partition	PartitionId
numSplits	int
datastore	Datastore
readTime	Timestamp

Returns
Type	Description
List<Query>

Exceptions
Type	Description
DatastoreException