io.debezium.connector.postgresql.spi

Interface Snapshotter

All Known Implementing Classes:

AlwaysSnapshotter, ExportedSnapshotter, InitialOnlySnapshotter, InitialSnapshotter, NeverSnapshotter, QueryingSnapshotter

@Incubating
public interface Snapshotter

This interface is used to determine details about the snapshot process: Namely: - Should a snapshot occur at all - Should streaming occur - What queries should be used to snapshot While many default snapshot modes are provided with debezium (see documentation for details) a custom implementation of this interface can be provided by the implementor which can provide more advanced functionality, such as partial snapshots Implementor's must return true for either shouldSnapshot() or shouldStream() or true for both.

Method Summary

Modifier and Type	Method and Description
Optional<String>	buildSnapshotQuery(TableId tableId) Generate a valid postgres query string for the specified table, or an empty Optional to skip snapshotting this table (but that table will still be streamed from)
default boolean	exportSnapshot()
void	init(PostgresConnectorConfig config, OffsetState sourceInfo, SlotState slotState)
boolean	shouldSnapshot()
boolean	shouldStream()
default Optional<String>	snapshotTableLockingStatement(Duration lockTimeout, Set<TableId> tableIds) Returns a SQL statement for locking the given tables during snapshotting, if required by the specific snapshotter implementation.
default String	snapshotTransactionIsolationLevelStatement(SlotCreationResult newSlotInfo) Return a new string that set up the transaction for snapshotting

Method Detail

init

void init(PostgresConnectorConfig config,
          OffsetState sourceInfo,
          SlotState slotState)

shouldSnapshot

boolean shouldSnapshot()

Returns:

true if the snapshotter should take a snapshot

shouldStream

boolean shouldStream()

Returns:

true if the snapshotter should stream after taking a snapshot

exportSnapshot

default boolean exportSnapshot()

Returns:

true if when creating a slot, a snapshot should be exported, which can be used as an alternative to taking a lock

buildSnapshotQuery

Optional<String> buildSnapshotQuery(TableId tableId)

Generate a valid postgres query string for the specified table, or an empty Optional to skip snapshotting this table (but that table will still be streamed from)

Parameters:

tableId - the table to generate a query for

Returns:

a valid query string, or none to skip snapshotting this table

snapshotTransactionIsolationLevelStatement

default String snapshotTransactionIsolationLevelStatement(SlotCreationResult newSlotInfo)

Return a new string that set up the transaction for snapshotting

Parameters:

newSlotInfo - if a new slow was created for snapshotting, this contains information from the `create_replication_slot` command

snapshotTableLockingStatement

default Optional<String> snapshotTableLockingStatement(Duration lockTimeout,
                                                       Set<TableId> tableIds)

Returns a SQL statement for locking the given tables during snapshotting, if required by the specific snapshotter implementation.