Redis cache tags flush cause Error while writing bytes to the server

[MoishyTlushTakin]

Laravel Version

12.35

PHP Version

8.3.6

Database Driver & Version

Valkey 8.1

Description

When Trying to flush cache()->tags($tags)->flush(); when there very much keys under this tags, it fails to write the LUA scipt to the server becaude of buffer size, when using Predis in the Predis\Connection\StreamConnection:295 in the write function when perform fwrite($socket, $buffer) it return 0, I think the anser it to chunk the LUA script to chunks let's say 1000 keys in chunk

Steps To Reproduce

in laravel project run the code
function test_tags_flush(array $tags){
foreach (range(1,5000) as $key => $value) {
cache()->tags($tags)->put("key:{$key}", "value:{$value}", 300);
}
cache()->tags($tags)->flush();
}

test_tags_flush(['test-tags-flush']);

[github-actions]

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If possible, please make a pull request fixing the issue you have described, along with corresponding tests. All pull requests are promptly reviewed by the Laravel team.

Thank you!

[faisuc]

I can confirm this is a real issue. Just dug through the code and the problem is pretty clear.

In RedisTaggedCache::flush() (lines 138-160), when you're not using a clustered connection, it collects ALL the keys into an array and then tries to pass them all at once to a single LUA script via eval():

foreach ($this->tags->entries() as $entry) {
    $keysToBeDeleted[] = $this->store->getPrefix().$entry;
}

$connection->eval(
    $script,
    count($keysToBeDeleted),
    ...$keysToBeDeleted,  // spreading 5000+ keys here
    ...[$cachePrefix, ...$cacheTags]
);

With 5000 keys, that's a huge amount of data being shoved through fwrite() in one go, which is why Predis is choking on it.

The funny thing is, Laravel already handles this correctly for clustered connections. Check out flushValues() on line 189:

protected function flushValues()
{
    $entries = $this->tags->entries()
        ->map(fn (string $key) => $this->store->getPrefix().$key)
        ->chunk(1000);  // chunks it into batches

    foreach ($entries as $cacheKeys) {
        $this->store->connection()->del(...$cacheKeys);
    }
}

So basically the clustered path uses chunking but the non-clustered path doesn't, which seems like an oversight. The fix would be to apply the same chunking approach to the regular flush() method.

[varunkasyap]

We should close this issue, if i am not wrong