Hello all, I was wondering if someone could help me with a seemingly trivial issue that I'm unable to figure out. I have the following code:
redisTemplate.multi();
redisTemplate.opsForHash().putIfAbsent(key, hashKey, String.valueOf(value));
redisTemplate.opsForHash().get(key, hashKey);
List<Object> result = redisTemplate.exec();The result that I get is just a boolean which is the output of the putIfAbsent(), and I never get the output of get(). Am I missing something, or is this the expected behaviour? What shall I do to get the value from the transaction?
Ok, I managed to find a workaround by using the increment command. But for reasons unrelated to the above problem, I get the the following error:
org.springframework.data.redis.RedisSystemException: Error in execution; nested exception is io.lettuce.core.RedisCommandExecutionException: ERR EXEC without MULTI
at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:54)
at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:52)
at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:41)
at org.springframework.data.redis.PassThroughExceptionTranslationStrategy.translate(PassThroughExceptionTranslationStrategy.java:44)
at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:42)
at org.springframework.data.redis.connection.lettuce.LettuceConnection.convertLettuceAccessException(LettuceConnection.java:270)
at org.springframework.data.redis.connection.lettuce.LettuceConnection.exec(LettuceConnection.java:667)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.data.redis.core.RedisConnectionUtils$ConnectionSplittingInterceptor.invoke(RedisConnectionUtils.java:381)
at org.springframework.data.redis.core.RedisConnectionUtils$ConnectionSplittingInterceptor.intercept(RedisConnectionUtils.java:359)
ByteBuffer. For every other case it does not work well.
String in ScanArgs
ScanIterator utility that simplifies the SCAN API usage by hiding multiple SCAN calls behind an Iterator API.
RedisClusterClient sounds the most appropriate way to go. In doubt, run the INFO command and check out the cluster and replication section for which one is enabled.
MasterReplica and provide all hosts so that Lettuce is able to determine roles of each node in the replica setup.
StatefulRedisClusterConnection I am able to get the RedisClusterNode for given slot, and I can even figure out list of replicas. But I am not able convert RedisClusterNodeinto *AsyncCommand interface.
REPLICA_PREFERRED and kill one of my replicas in cluster I keep getting error and failover to master never happens. Despite the fact I have cluster refresh topology configured like this:val timeoutOptions = TimeoutOptions.builder()
.timeoutCommands(true)
.connectionTimeout()
.fixedTimeout(Duration.ofMillis(500))
.build()
val clusterTopologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
.enableAllAdaptiveRefreshTriggers()
.refreshTriggersReconnectAttempts(3)
.enablePeriodicRefresh(true)
.enablePeriodicRefresh(Duration.ofSeconds(15))
.dynamicRefreshSources(true)
.build()
val connectionOptions = ClusterClientOptions.builder()
.timeoutOptions(timeoutOptions)
.topologyRefreshOptions(clusterTopologyRefreshOptions)
.build()
return RedisClusterClient.create(url).apply {
setOptions(connectionOptions)
setDefaultTimeout(Duration.ofSeconds(1))
}.connect().apply {
readFrom = ReadFrom.REPLICA_PREFERRED
}StatefulRedisClusterConnection as singleton
reloadPartitions
connectAsync I have to call getPartition which is a blocking API
String.
SCAN may return without results but without necessarily completing. COUNT is a hint how many iterations Redis does on the server side when attempting to find keys. See https://redis.io/commands/scan for further details.
I am new to Lettuce and exploring the Lettuce library for our redis cluster setup with Master-Slave-Sentinel deployment.
I have the following deployment presently -
1] Bunch of master redis instances
2] Bunch of slave redis instances (1 slave per master)
3] Bunch of sentinels monitoring all the Master/Slave instances
4] All in Kubernetes
I need the following functionality -
1] Client to connect to sentinel for getting the cluster state
2] Client writer to partition data evenly across all masters by key to be flushed to the bunch of masters
3] Client writer should have ability to receive notifications of new masters (which were slaves earlier) when there is a failover of an existing master
& the ability to update the in memory state of the cluster dynamically.
4] Client should have the ability to pipeline the requests for better performance
5] The connections to every redis instance should support pooling
6] The ability to scale up and down the number of masters-slave nodes with the client seamlessly able to catch up with the cluster state dynamically
I would like to know whether Lettuce library can support all the things I have listed above.