[case37]聊聊lettuce的shareNativeConnection参数

序

本文主要研究一下lettuce的shareNativeConnection参数

LettuceConnectionFactory

spring-data-redis-2.0.10.RELEASE-sources.jar!/org/springframework/data/redis/connection/lettuce/LettuceConnectionFactory.java

public class LettuceConnectionFactory
        implements InitializingBean, DisposableBean, RedisConnectionFactory, ReactiveRedisConnectionFactory {

    private static final ExceptionTranslationStrategy EXCEPTION_TRANSLATION = new PassThroughExceptionTranslationStrategy(
            LettuceConverters.exceptionConverter());

    private final Log log = LogFactory.getLog(getClass());
    private final LettuceClientConfiguration clientConfiguration;

    private @Nullable AbstractRedisClient client;
    private @Nullable LettuceConnectionProvider connectionProvider;
    private @Nullable LettuceConnectionProvider reactiveConnectionProvider;
    private boolean validateConnection = false;
    private boolean shareNativeConnection = true;
    private @Nullable SharedConnection<byte[]> connection;
    private @Nullable SharedConnection<ByteBuffer> reactiveConnection;
    private @Nullable LettucePool pool;
    /** Synchronization monitor for the shared Connection */
    private final Object connectionMonitor = new Object();
    private boolean convertPipelineAndTxResults = true;
    private RedisStandaloneConfiguration standaloneConfig = new RedisStandaloneConfiguration("localhost", 6379);
    private @Nullable RedisSentinelConfiguration sentinelConfiguration;
    private @Nullable RedisClusterConfiguration clusterConfiguration;
    private @Nullable ClusterCommandExecutor clusterCommandExecutor;

    //......

    @Override
    public LettuceReactiveRedisConnection getReactiveConnection() {

        return getShareNativeConnection()
                ? new LettuceReactiveRedisConnection(getSharedReactiveConnection(), reactiveConnectionProvider)
                : new LettuceReactiveRedisConnection(reactiveConnectionProvider);
    }

    @Override
    public LettuceReactiveRedisClusterConnection getReactiveClusterConnection() {

        if (!isClusterAware()) {
            throw new InvalidDataAccessApiUsageException("Cluster is not configured!");
        }

        RedisClusterClient client = (RedisClusterClient) this.client;

        return getShareNativeConnection()
                ? new LettuceReactiveRedisClusterConnection(getSharedReactiveConnection(), reactiveConnectionProvider, client)
                : new LettuceReactiveRedisClusterConnection(reactiveConnectionProvider, client);
    }

    /**
     * Indicates if multiple {@link LettuceConnection}s should share a single native connection.
     *
     * @return native connection shared.
     */
    public boolean getShareNativeConnection() {
        return shareNativeConnection;
    }

    /**
     * @return the shared connection using {@link ByteBuffer} encoding for reactive API use. {@literal null} if
     *         {@link #getShareNativeConnection() connection sharing} is disabled.
     * @since 2.0.1
     */
    @Nullable
    protected StatefulConnection<ByteBuffer, ByteBuffer> getSharedReactiveConnection() {
        return shareNativeConnection ? getOrCreateSharedReactiveConnection().getConnection() : null;
    }

    private SharedConnection<ByteBuffer> getOrCreateSharedReactiveConnection() {

        synchronized (this.connectionMonitor) {

            if (this.reactiveConnection == null) {
                this.reactiveConnection = new SharedConnection<>(reactiveConnectionProvider, true);
            }

            return this.reactiveConnection;
        }
    }
}

• 可以看到这里的shareNativeConnection默认为true，表示多个LettuceConnection将共享一个native connection
• 如果该值为true，则getReactiveConnection及getReactiveClusterConnection方法使用的是getSharedReactiveConnection
• getSharedReactiveConnection在shareNativeC