Redis pipeline memory leak?

[TrystanLea]

Hello, Im using the following code to load in input data in our application (https://github.com/emoncms/emoncms/)

    $pipe = $this->redis->multi(Redis::PIPELINE);
    foreach ($inputids as $id) {
        $pipe->hGetAll("input:$id");
    }
    $result = $pipe->exec();

This seems to give me a memory leak with the latest version of phpredis develop branch and php 8.1.23 (raspberrypi os 32-bit, may 3rd debian 11 bullseye, kernel 6.1.21-v8+.

The issue remains with hMGet but is not present with hGet with a single key.

This has been working fine for years without the memory issue and seems to have only become apparent this year, first reported issue around April 2023

Let me know if there is any other information that I can provide to assist in any way.

[mfn]

(Tried to) upgrade to Redis 6 today and confirm, the pipeline feature leaks memory.

This short script was enough to trigger the linux OOM:

<?php

$redis = new Redis();
$redis->connect('redis');

while (true) {
    $redis->pipeline();
    $redis->exec();
}

=> with 6.0.0 it's killed after a minute or so (depending on the RAM of the [virtual] machine, so be careful)

root@e0acc6751f6c:/prject# php test_redis.php
Killed

=> with 5.3.7 no problems, runs and runs

[mfn]

Using git bisect I found this being the breaking commit 5a643b6 , which is part of #2326 .

Whilst doing this I also found #2390 , it was actually part of the same commit which introduced the leak.

[yatsukhnenko]

@TrystanLea @mfn issue should be fixed in develop branch, could you test it?

[mfn]

@yatsukhnenko with my test script I can confirm I can't reproduce the memory leak nor the crash!

edit: I tested with 6.0.1 installed via pecl, since I saw it was already taggad. Not sure if there's a way to test the main/master/develop branch diretly via pecl? But I figure that it's good enough 🤞🏼

[TrystanLea]

All working fine for me now, thanks a lot for fixing this!