Examples with MapSerializerSnapshot org.apache.flink.api.common.typeutils.base.MapSerializerSnapshot used on opensource projects

Example 1 with MapSerializerSnapshot

use of org.apache.flink.api.common.typeutils.base.MapSerializerSnapshot in project flink by apache.

the class RocksDBKeyedStateBackend method migrateStateValues.

/**
 * Migrate only the state value, that is the "value" that is stored in RocksDB. We don't migrate
 * the key here, which is made up of key group, key, namespace and map key (in case of
 * MapState).
 */
@SuppressWarnings("unchecked")
private <N, S extends State, SV> void migrateStateValues(StateDescriptor<S, SV> stateDesc, Tuple2<ColumnFamilyHandle, RegisteredKeyValueStateBackendMetaInfo<N, SV>> stateMetaInfo) throws Exception {
    if (stateDesc.getType() == StateDescriptor.Type.MAP) {
        TypeSerializerSnapshot<SV> previousSerializerSnapshot = stateMetaInfo.f1.getPreviousStateSerializerSnapshot();
        checkState(previousSerializerSnapshot != null, "the previous serializer snapshot should exist.");
        checkState(previousSerializerSnapshot instanceof MapSerializerSnapshot, "previous serializer snapshot should be a MapSerializerSnapshot.");
        TypeSerializer<SV> newSerializer = stateMetaInfo.f1.getStateSerializer();
        checkState(newSerializer instanceof MapSerializer, "new serializer should be a MapSerializer.");
        MapSerializer<?, ?> mapSerializer = (MapSerializer<?, ?>) newSerializer;
        MapSerializerSnapshot<?, ?> mapSerializerSnapshot = (MapSerializerSnapshot<?, ?>) previousSerializerSnapshot;
        if (!checkMapStateKeySchemaCompatibility(mapSerializerSnapshot, mapSerializer)) {
            throw new StateMigrationException("The new serializer for a MapState requires state migration in order for the job to proceed, since the key schema has changed. However, migration for MapState currently only allows value schema evolutions.");
        }
    }
    LOG.info("Performing state migration for state {} because the state serializer's schema, i.e. serialization format, has changed.", stateDesc);
    // we need to get an actual state instance because migration is different
    // for different state types. For example, ListState needs to deal with
    // individual elements
    StateFactory stateFactory = STATE_FACTORIES.get(stateDesc.getType());
    if (stateFactory == null) {
        String message = String.format("State %s is not supported by %s", stateDesc.getClass(), this.getClass());
        throw new FlinkRuntimeException(message);
    }
    State state = stateFactory.createState(stateDesc, stateMetaInfo, RocksDBKeyedStateBackend.this);
    if (!(state instanceof AbstractRocksDBState)) {
        throw new FlinkRuntimeException("State should be an AbstractRocksDBState but is " + state);
    }
    @SuppressWarnings("unchecked") AbstractRocksDBState<?, ?, SV> rocksDBState = (AbstractRocksDBState<?, ?, SV>) state;
    Snapshot rocksDBSnapshot = db.getSnapshot();
    try (RocksIteratorWrapper iterator = RocksDBOperationUtils.getRocksIterator(db, stateMetaInfo.f0, readOptions);
        RocksDBWriteBatchWrapper batchWriter = new RocksDBWriteBatchWrapper(db, getWriteOptions(), getWriteBatchSize())) {
        iterator.seekToFirst();
        DataInputDeserializer serializedValueInput = new DataInputDeserializer();
        DataOutputSerializer migratedSerializedValueOutput = new DataOutputSerializer(512);
        while (iterator.isValid()) {
            serializedValueInput.setBuffer(iterator.value());
            rocksDBState.migrateSerializedValue(serializedValueInput, migratedSerializedValueOutput, stateMetaInfo.f1.getPreviousStateSerializer(), stateMetaInfo.f1.getStateSerializer());
            batchWriter.put(stateMetaInfo.f0, iterator.key(), migratedSerializedValueOutput.getCopyOfBuffer());
            migratedSerializedValueOutput.clear();
            iterator.next();
        }
    } finally {
        db.releaseSnapshot(rocksDBSnapshot);
        rocksDBSnapshot.close();
    }
}