Cassandra 查询超时，当明确指定为 LOCAL_QUORUM 时，将一致性视为 ALL

Question

Cassandra 查询为选择查询超时:

SELECT x, y FROM <table> WHERE unique_id= <value>

有这个特例

com.datastax.driver.core.exceptions.ReadTimeoutException: Cassandra timeout during read query at consistency ALL (3 responses were required but only 2 replica responded)
    at com.datastax.driver.core.exceptions.ReadTimeoutException.copy(ReadTimeoutException.java:88)
    at com.datastax.driver.core.exceptions.ReadTimeoutException.copy(ReadTimeoutException.java:25)
    at com.datastax.driver.core.DriverThrowables.propagateCause(DriverThrowables.java:37)
    at com.datastax.driver.core.DefaultResultSetFuture.getUninterruptibly(DefaultResultSetFuture.java:245)

Cassandra 驱动程序:

<dependency>
    <groupId>com.datastax.cassandra</groupId>
    <artifactId>cassandra-driver-core</artifactId>
    <version>3.5.0</version>
</dependency>

我们的查询代码:

    QueryOptions queryOptions = new QueryOptions();
    queryOptions.setSerialConsistencyLevel(ConsistencyLevel.LOCAL_SERIAL);
    queryOptions.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);

    List<String> contactPoints = Utils
        .getArrayStrings(config, Constants.CASSANDRA_CONTACT_POINTS);

    Cluster cluster = Cluster.builder()
        .addContactPoints(contactPoints.toArray(new String[contactPoints.size()]))
        .withQueryOptions(queryOptions)
        .withProtocolVersion(ProtocolVersion.V4)
        .build();

    Session session = cluster.connect();
    session.executeAsync(SELECT_STATEMENT).bind()
                .setUUID(0, UUID.fromString(inputEvent.getUniqueId()))

当我们在查询选项中将一致性显式设置为 LOCAL_QUORUM 时，为什么将一致性视为 ALL？

Answer 1

我们在生产环境中遇到了同样的问题。看起来它与这里描述的读取修复过程有关CASSANDRA-10726 .同样在此副本中 CASSANDRA-14480错误其他人有确切的行为。

我们只有在切换到多 DC 环境后才注意到此错误。

我们正在使用这个版本:

Cassandra :3.0.15
DSE:5.0.12
Java 驱动程序:3.1.4