Jedis pool configuration for get and set/flush operations - redis

I am new to redis and using Jedis client in my application. I have gone through couple of threads and did not find the conclusive answers.
I have 2 questions where I need clarity.
For my production use I want to set separate timeout for jedis get operations and set operations. For all set operation I want to set timeout to 2000ms and for get 100ms. I have implemented below configuration.
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxIdle(30);
poolConfig.setMinIdle(10);
poolConfig.setMaxWaitMillis(2000);
jedisPool = new JedisPool(poolConfig, RedisDBUrl, port, 100);
Let me know if above configuration will do the job. I am setting read timeout to 100ms and maxwait to 2000ms.
Let me know if my understanding is correct.
At times I get JedisConnectionException: java.net.SocketTimeoutException: Read timed out or sometimes connect timeout.
Here connect time out is thrown when my application is not able to make connection to redis withing configured time?
Secondly, read timeout comes when application is connected to redis but operations(get/set) are taking time or for some reason?
Lastly, how do i configure timeout for read timeout and connect timeout?

After many hit and trial and some test runs found out, you can not set separate timeout for jedis get and set operations.
May be you can use some external library to achieve(Like google's SimpleTimeLimiter.
Further from what I have observed connect timeout occurs when jedis tries to connect to redis server. In my case my redis server latency from my system is ~120-125ms so if I set timeout=100ms in jedis constructor I get "connect time out".
Whereas "read time out" comes when you are connected to redis server but redis operation doesn't return in specified time. To test this scenario I have set the timeout in constructor to 180ms and tried to run the flushall operation(takes long time), here I got read timeout.
Still not sure though whats the significance of poolConfig.setMaxWaitMillis().

Related

Moleculer JS "Redis-pub client is disconnected" every 10 minutes

my application (Node.js) is using moleculer for microservices and redis as transporter. However, I find that the application will have this log Redis-pub client is disconnected every 10 minutes, then reconnect with the log Redis-pub client is connected after a few seconds. This is a problem because if a client send a moleculer action during this time, it will fail.
Any idea what is causing this? Let me know if more information is needed.
Azure Cache for Redis currently has a 10-minute idle timeout for connections, so the idle timeout setting in your client application should be less than 10 minutes. Most common client libraries have a configuration setting that allows client libraries to send Redis PING commands to a Redis server automatically and periodically. However, when using client libraries without this type of setting, customer applications themselves are responsible for keeping the connection alive.
More info: https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-best-practices-connection#idle-timeout

Timeout exception (wcf) while running python script

I am running a python script that controls an ADI software named ACE capturing data remotely through port 8080. The ACE will attempt to create an IPC server on the port number. It takes around 12 minutes to capture 1 data set. The script runs normally for capture under 10 minutes. I suspects that the exception occurs because the default ReceiveTimeout is 10 minutes.
I adjusts the ReceiveTimeout in the SMSvcHost.exe.config file but it still not fix the issue. Other threads suggest that I need to adjust the ReceiveTimeout in app.config/ web.config. I am not sure how to locate these file. I am worried I might make changes to the wrong config file. Please advise!
Tracing Information:
[1]: https://i.stack.imgur.com/AKeHA.png
Here is the error message
This request operation sent to net.tcp://localhost:8080/ did not receive a reply within the configured timeout (00:10:00). The time allotted to this operation may have been a portion of a longer timeout. This may be because the service is still processing the operation or because the service was unable to send a reply message. Please consider increasing the operation timeout (by casting the channel/proxy to IContextChannel and setting the OperationTimeout property) and ensure that the service is able to connect to the client.

Debugging Redisson Subscribe Timeouts

I am using Redisson 3.8.2 to connect to a replicated AWS elasticache, after a while of operation my client frequently gets timeout exceptions trying to subscribe to topics.
I've checked the load on AWS and the load on my client, AWS is barely above idle and the client has far fewer subscriptions than it should be able to support (subscriber pool * subscriptions per connection).
I have tried adjusting the subscription connection pool and subscribers per connections settings but still get the issue.
The exception is thrown at a high level, timing out waiting for the Redisson promise to sync, looking through the detail code behind the promise there is a lot happening involving at least 2 locks in the java code and async futures to subscribe and attach the listener.
Is there a way I can get more debugging information from Redisson about where is it timing out / what stage it is getting to and when it fails seeing what the state of the connection pools and the connection entries are?
org.redisson.client.RedisTimeoutException: Subscribe timeout: (7500ms)
at org.redisson.command.CommandAsyncService.syncSubscription(CommandAsyncService.java:142) ~[redisson-3.8.2.jar!/:na]
at org.redisson.RedissonTopic.addListener(RedissonTopic.java:133) ~[redisson-3.8.2.jar!/:na]
at org.redisson.RedissonTopic.addListener(RedissonTopic.java:109) ~[redisson-3.8.2.jar!/:na]

When does Resque open a redis connection?

I've been running into Redis::TimeoutError: Connection timed out errors on Heroku, and I'm trying to pin down the problem. I'm only using Resque to connect to redis, so I'm wondering how Resque connects to redis:
When does Resque connect to redis? When a worker is started?
How long do redis connections last, typically?
It's unclear to me when connections are made and how long they last. Can anyone shed some light on this for me? Thanks!
Typically connections to Redis from Rails apps are established lazily, when the connection is first time used. For troubleshooting, sometimes it is useful to force the connection by adding Redis PING (http://redis.io/commands/ping) in the initializer code.
Once connection is established it will be maintained forever. If connection is dropped, an attempt to reconnect will happen next time it is used.
Also, be aware that as of early 2015, Heroku had an ongoing issue establishing connections to Redis instances on AWS, as the connections would occasionally time out. Heroku support is aware of that, so you may be able to get some help reaching out to them.

jedis connection settings for high performance and reliablity

I am using Jedis client for connecting to my Redis server. The following are the settings I'm using for connecting with Jedis (using apache common pool):
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setTestOnBorrow(true);
poolConfig.setTestOnReturn(true);
poolConfig.setMaxIdle(400);
// Tests whether connections are dead during idle periods
poolConfig.setTestWhileIdle(true);
poolConfig.setMaxTotal(400);
// configuring it for some good max value so that timeout don't occur
poolConfig.setMaxWaitMillis(120000);
So far with these setting I'm not facing any issues in terms of reliability (I can always get the Jedis connection whenever I want), but I am seeing a certain lag with Jedis performance.
Can any one suggest me some more optimization for achieving high performance?
You have 3 tests configured:
TestOnBorrow - Sends a PING request when you ask for the resource.
TestOnReturn - Sends a PING whe you return a resource to the pool.
TestWhileIdle - Sends periodic PINGS from idle resources in the pool.
While it is nice to know your connections are still alive, those onBorrow PING requests are wasting an RTT before your request, and the other two tests are wasting valuable Redis resources. In theory, a connection can go bad even after the PING test so you should catch a connection exception in your code and deal with it even if you send a PING. If your network is stable, and you do not have too many drops, you should remove those tests and handle this scenario in your exception catches only.
Also, by setting MaxIdle == MaxTotal, there will be no eviction of resources from your pool (good/bad?, depends on your usage). And when your pool is exhausted, an attempt to get a resource will endup in timeout after 2 minutes of waiting for a free resource.