Redis Pipelining is a technique that helps to reduce the round-trip time between the Redis server and the client. In this article, we will explore the Redis Pipelining in Node.js.
Before we start, let's first understand the time between round trips involved in executing Redis commands between the server and client.
The client sends a Redis query to the Redis server.
The Redis server processes this query and responds to the client.
For each Redis command, this request-response cycle continues.
MULTI Command In Redis
The MULTI command in the Redis allows the execution of multiple Redis commands in a single step.
Syntax
Using Redis Multi and Pipeline in NodeJS
In Node.js, Redis clients have two main methods for batching commands and creating transactions. One is the Redis multi command, mentioned above, and the other is the pipeline method.
In this article, we will be using the node-redis package.
Install
npm i redis
Multi with node-redis
The MULTI command in Redis executes a group of commands as atomic transactions to ensure data integrity. This means that all commands in the block are either executed or none are.
Redis example of multi
const redis = require("redis");
const client = redis.createClient();
const execMulti = () => {
const multi = client.multi();
multi.set("key1", "value1");
multi.set("key2", "value2");
multi.get("key1");
multi.get("key2");
const multiExec = multi.exec();
multiExec
.then((res) => {
console.log("Multi commands executed successfully");
console.log(res);
client.quit();
})
.catch((err) => {
console.log("Error executing multi commands");
console.log(err);
});
};
client.on("error", (err) => {
console.log("Redis Client Error", err);
});
client
.connect()
.then(() => {
console.log("Connected to Redis");
execMulti();
})
.catch((err) => {
console.log(err);
});
Pipeline with node-redis
The pipeline feature of the node-redis client allows batching of multiple commands but does not guarantee atomicity.
Node Redis can automatically group multiple requests made during the same "tick, " meaning if commands are in a single cycle of the event loop, the node-redis client can combine them into a single pipeline.
Auto-Pipelining example in Node Redis
const redis = require("redis");
const client = redis.createClient();
client.on("error", (err) => {
console.error("Redis client error", err);
});
client
.connect()
.then(() => {
console.log("Connected to Redis");
Promise.all([
client.set("key", "value"),
client.get("key"),
client.set("key1", 1),
client.incr("key1"),
client.get("key1"),
])
.then((results) => {
console.log("SET", results[0]);
console.log("GET", results[1]);
console.log("SET", results[2]);
console.log("INCR", results[3]);
console.log("GET", results[4]);
client.quit();
})
.catch((err) => {
console.error("Error setting/getting from Redis", err);
});
})
.catch((err) => {
console.error("Error connecting to Redis", err);
});
Output
Connected to Redis
SET OK
GET value
SET OK
INCR 2
GET 2
Node-redis client also contains execAsPipeline() method for manual batching of redis commands
Example using execAsPipeline method
const redis = require("redis");
const client = redis.createClient();
client.on("error", (err) => {
console.error("Redis client error", err);
});
client
.connect()
.then(async () => {
console.log("Connected to Redis");
let pipeline = client.multi();
pipeline.set("key1", "value1");
pipeline.set("key2", "value2");
pipeline.get("key1");
pipeline.get("key2");
let result = await pipeline.execAsPipeline();
console.log(result);
client.quit();
})
.catch((err) => {
console.error("Error connecting to Redis", err);
});
output
Connected to Redis
[ 'OK', 'OK', 'value1', 'value2' ]
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