Package io.github.flink.gcp.connector.spanner.source

Class SpannerSource

java.lang.Object

io.github.flink.gcp.connector.spanner.source.SpannerSource

@Public
public final class SpannerSource
extends Object

Reads rows from a Cloud Spanner database.

 Source<Singer, ?, ?> source =
         SpannerSource.<Singer>builder()
                 .database(DatabaseDestination.of("my-project", "my-instance", "my-db"))
                 .readOperation(
                         SpannerReadOperation.query(
                                 Statement.of("SELECT id, name FROM singers")))
                 .deserializer(mySingerDeserializer)
                 .build();
 

The read is bounded: the source reads the rows the operation names, at one snapshot, and finishes. That is not the same as batch-only — a bounded source runs inside a streaming pipeline and simply ends, which is what makes reading a Spanner table and joining it against an unbounded stream work.

Every subtask reads the same snapshot. The source asks Spanner to divide the read into partitions at one timestamp, and each subtask rejoins that transaction to read the partitions it was given. There is no column to split on and no bounds to supply: where the divisions fall is the service's decision, made from how the data is actually stored.

Method Summary

Modifier and Type	Method	Description
static <T> SpannerSourceBuilder<T>	builder()	Returns a builder for a Spanner batch source.

Methods inherited from class java.lang.Object

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

Method Details

builder

public static <T> SpannerSourceBuilder<T> builder()

Returns a builder for a Spanner batch source.

Type Parameters:

T - the record type produced

Returns:

the builder