pubsub

configured in the redis.conf file: Config get Client-output-buffer-limit 1) "Client-output-buffer-limit" 2) "Normal 0 0 0 slave 268435456 67108864 pubsub 33554432 8388608" Output buffer is a buffer allocated by Redis to the client (the "client" may be a real client or a slave or monitor), and if the output buffer assigned to a client exceeds the reserved size, Redis may turn off connections to that end based on the configura

Two basic design patterns.1.PubSub Mode is a callback organization that assigns callbacks to named eventsA 2.Promise object is a visual object that represents a one-time event.and async.js workflow control, Async Utilities for node and the browserHttps://github.com/caolan/asyncAnd Tim Caswell's Step① is a lightweight JavaScript library.Https://github.com/creationix/step1.PubSub (Publish/subscribe, meaning "

, the clients that have subscribed to these channels will automatically receive these messages. Finally, we will pass these messages throughSSEPush to the client.3. Implementation After the above analysis, the entire chat room process has been very clear. The following is an analysis by using source code annotations. In/home/shiyanlouDirectory to create a directorycodeAnd then create the source file in this directory.app.py # Message generator def event_stream ():

Websocket Application Messaging Protocol protocol: Https://github.com/wamp-proto/wamp-proto1. Basic ArchivesIntroduced:The WAMP protocol is a communication protocol that can be publishsubscribe and RPC based on WebSocket. It realizes the pubsub communication pattern similar to the ZEROMQ, and uses this mode for the traditional RPC communication, which is a good way to decouple the direct connection between the communication endpoints.Basic concepts:Br

clients to listen to the message queue, once the message arrives, consumers immediately consume, who first grabbed the count, if there is no message in the queue, then consumers continue to monitor. The latter is also one or more clients subscribing to the message channel, so long as the publisher publishes the message, all Subscribers are able to receive the message and the subscribers are ping.Production and consumption patternsThe main use of Redis-provided blpop to get the queue data, if th

The following code demonstrates the use of the first two methods to implement publications and subscriptions. var test = ko.observable (); Create a subscription for the "Test-event" test.subscribe (function (val) { console.log (val); }, Test, " Test-event "); Test.notifysubscribers ("Hello World", "test-event"); One of the cool features of subscriptions in knockout is that it can be mixed into any Javascript object, and the following code sho

, in an async function, you cannot use Try/catch to catch exceptions.Distributed eventsThe event core of JavaScript is the event distribution mechanism, which achieves asynchronous response by binding a subscription handle to the Publisher: Document.onclick = function () { Click }； PubSub (Publish/subscribe, publish/subscribe) mode is a pattern that achieves multi-tier distribution decoupling by subscribing to the publisher's eve

called Nscollectionview. At the same time, there is an example called PubSub that uses Ikimagebrowserview, and you can find this example in the/developer/examples/pubsub/newmusic/directory.Set up your own smart groups, playlists, directoriesYou can use the two classes of Nsruleeditor and Nspredicateeditor to develop a familiar rule editing interface.Add a custom view to the menuNsmenuitem now provides a-se

Introduced The observer pattern, also known as the Publish subscription model (Publish/subscribe), defines a one-to-many relationship in which multiple observer objects listen to a Subject object at the same time, and the subject object's state changes to notify all observer objects so that they can automatically update themselves. Benefits of using the Observer pattern: 1. Support Simple broadcast communication and automatically notify all objects that have been subscribed to.2. The target o

unclear. 5. Observer Mode We assume that there is a "signal center". When a task is completed, a signal is published to the signal center (publish). Other tasks can subscribe to the signal center) this signal to know when you can start execution. This is called publish-subscribe pattern and observer pattern ). Var pubsub = (function () {var q = {} topics = {}, subUid =-1; // publish message q. publish = function (topic, args) {if (! Topics [topic])

bytes are in a compact storage format.Zset-max-ziplist-entries 128Zset-max-ziplist-value 64# Redis will use 1 milliseconds of CPU time every 100 milliseconds to re-hash the Redis hash table, which can reduce the use of memory# When you have a very strict real-time requirement in your usage scenario, you cannot accept Redis's occasional 2 millisecond delay for requests, and configure this as No.# If you don't have such strict real-time requirements, you can set it to Yes so that you can free up

disconnection (a common reason is that a publish/subscribe client consumes messages at a rate that cannot catch up with the speed at which they are produced).# can be set in three different ways for clients:# Normal Client# slave-Slave and MONITOR client# PubSub has subscribed to at least one pubsub channel or pattern client# each CLIENT-OUTPUT-BUFFER-LIMIT syntax:# Client-output-buffer-limit# Once the har

-truncated YesLua-time-limit 5000Slowlog-log-slower-than 10000Slowlog-max-len 128Latency-monitor-threshold 0Notify-keyspace-events ""Hash-max-ziplist-entries 512Hash-max-ziplist-value 64List-max-ziplist-size-2List-compress-depth 0Set-max-intset-entries 512Zset-max-ziplist-entries 128Zset-max-ziplist-value 64Hll-sparse-max-bytes 3000activerehashing YesClient-output-buffer-limit Normal 0 0 0Client-output-buffer-limit slave 256MB 64MB 60Client-output-buffer-limit

aggregate computing, pubsub, and scripting. For such functions, you need to understand their implementation principles, you can use pubsub correctly only after you understand its limitations. For example, the pubsub function does not support persistence, all messages sent from the consumer's transient disconnection or reconnection will be lost. For example, func

in different languagesFor clients in different languages, memcached and redis both have a wide range of third-party clients to choose from. However, because memcached has been developing for a longer time, it is currently supported by clients, many clients of memcached are more mature and stable, while redis is more complicated than memcached because of its Protocol itself. In addition, due to the author's continuous addition of new features, the follow-up speed of the corresponding third-party

parameters: The first one is the length of the day in microseconds! , which is 1 per thousand of milliseconds. ）。 The second is the size of log, and the previous log will be deleted. # 1000000 is a second.Negative ValueAll requests are recorded log! Below is 0.10S. 100 milliseconds. Slowlog-log-slower-than 10000# Log Length setting value is unlimited. But memory is required. Slowlog-max-len 128################################ LATENCY MONITOR ############################### Use latency to print

function, using redis is more suitable than using memcached. Some peripheral functions of redis In addition to storage, redis also provides some other functions, such as aggregate computing, pubsub, and scripting. For such functions, you need to understand their implementation principles, you can use pubsub correctly only after you understand its limitations. For example, the

The main structure is: The Python process publishes messages, and the Java process subscribes to messages.Dependent environment:Python:pip Install RedisJava:jedis1. Python side:pubsub.pyImport Redisclass PubSub (object): def __init__ (self, host, port, db): self.__conn = Redis. Redis (host, port, DB) def publish (self, Channel, msg): self.__conn.publish (channel, msg) return True def subscribe (self, channel): pub

127.0.0.1:6379> PUBLISH Redischat "Learn Redis by w3cschool.cn" (integer) # Subscriber will display the following message 1) "Message" 2) "Redischat" 3) "Redis is a great caching Technique "1)" "Message" 2) "Redischat" 3) "Learn Redis by w3cschool.cn"The Psubscribe command subscribes to one or more channels that match a given pattern. Each pattern takes a * as a match, for example it* matches all channels that start with it (It.news, It.blog, It.tweets, and so on). News.* matches all with news.

real-time requirements, you can set to Yes so that you can free up memory as quickly as possible activerehashing Yes # The client's output buffer is limited because, for some reason, the client is not fast enough to read data from the server, # can be used to force a disconnect (a common cause is the speed at which a publish/subscribe client's consumer messages cannot catch up with the production of them). # can be set in three different client ways: # Normal-> Client # slave-> slave and