ARINSERT - Upstash Documentation

Use ARINSERT to append one or more values to the end of an array.

Each array keeps an append cursor holding the last index written by an append, so ARINSERT does not need to look up where the data ends: the first value goes to the slot after the cursor, the rest follow it, and the cursor moves to the last one. The reply is the index that last value received, which is what a producer records to point at what it just wrote.

Because the cursor is separate from the contents, appending is unaffected by deletions: freeing slots with ARDEL never causes a later append to reuse an index. Use ARSEEK to move the cursor deliberately and ARNEXT to read where the next append would land.

See the array command overview for the data model these commands share.

Syntax#

ARINSERT <key> <value> [<value> ...]

Arguments#

Argument	Required	Repeatable	Description
`<key>`	Yes	No	Array key targeted by the command.
`<value>`	Yes	Yes	Value to append. Repeat to append several values in one call.

Important points#

The reply is the index of the last value written, not the number of values written.
Appending past the highest supported index returns ERR insert index overflow.

Response#

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.

Protocol	Reply
RESP2	Integer, or bulk string when the index exceeds the signed 64-bit range
RESP3	Integer, or Big number when the index exceeds the signed 64-bit range

Note

Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.

Examples#

TCP examples use the TLS REDIS_URL from the Upstash console. REST examples use UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN.

Redis CLI

ARINSERT my-array hello world

@upstash/redis

Note

This command is not supported yet in @upstash/redis.

upstash_redis

Note

This command is not supported yet in upstash_redis.

ioredis

import Redis from "ioredis";const redis = new Redis(process.env.REDIS_URL!);const result = await redis.arinsert("my-array", "hello", "world");console.log(result);

node-redis

import { createClient } from "redis";const client = await createClient({ url: process.env.REDIS_URL })  .on("error", console.error)  .connect();const result = await client.arInsert("my-array", ["hello", "world"]);console.log(result);

redis-py

import osimport redisclient = redis.from_url(os.environ["REDIS_URL"])result = client.arinsert("my-array", "hello", "world")print(result)

go-redis

package mainimport (    "context"    "fmt"    "os"    "github.com/redis/go-redis/v9")func main() {    opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))    if err != nil {        panic(err)    }    client := redis.NewClient(opts)    result, err := client.ARInsert(context.Background(), "my-array", "hello", "world").Result()    if err != nil {        panic(err)    }    fmt.Println(result)}

jedis

import java.net.URI;import redis.clients.jedis.Jedis;try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {  Object result = jedis.arinsert("my-array", "hello", "world");  System.out.println(result);}

redis-rs

fn main() -> redis::RedisResult<()> {    let url = std::env::var("REDIS_URL").expect("REDIS_URL is not set");    let client = redis::Client::open(url)?;    let mut connection = client.get_connection()?;    let mut command = redis::cmd("ARINSERT");    command.arg("my-array");    command.arg("hello");    command.arg("world");    let result: redis::Value = command.query(&mut connection)?;    println!("{result:?}");    Ok(())}