Redis/Predis driver implementation error when using optPrefix

[MaximilianKresse]

What type of issue is this?

Incorrect/unexpected/unexplainable behavior

Connector/Database version (if applicable)

Redis and Predis

Phpfastcache version

9.1.2 ✅

Describe the issue you're facing

The redis and predis implementation of Driver::driverClear() method is currently incorrect when using the optPrefix setting. The current implementations just always call $this->instance->flushDB(); (redis and predis). This method is not effected by the prefix option and will simply wipe the current database clear.

Expected behavior

Driver::driverClear() should only clear the keys with the configured prefix.

Suggestion to fix the issue (optional)

The fixed driverClear method should look something like this:

if ($this->getConfig()->getOptPrefix() !== '') {
    return (bool) $this->instance->del(...$this->instance->keys('*'));
}
return $this->instance->flushDB();

Have you searched in our Wiki before posting ?

• [X] I have searched over the Wiki

[Geolim4]

The redis and predis implementation of Driver::driverClear() method is currently incorrect when using the optPrefix setting. The current implementations just always call $this->instance->flushDB(); (redis and predis). This method is not effected by the prefix option and will simply wipe the current database clear.

Unfortunately it's a known limitation of Redis/Predis with Flushdb, I can't really do something about it because of the reason below:

if ($this->getConfig()->getOptPrefix() !== '') {
    return (bool) $this->instance->del(...$this->instance->keys('*'));
}
return $this->instance->flushDB();

This code is a bit dangerous and not optimized because if the cache contains a lot of keys Phpfastcache will have a timeout/memory issue for sure. Retrieving all the keys from a cache is a red line that I always refused to do on Phpfastcache for performances reasons.

[MaximilianKresse]

Mhh ok I understand your point and also don't see any reliable way to do this without the risk of a memory issue. This behaviour should be documented as it may be unexpected. For now we'll try to use our own driver.

[Geolim4]

You can also create a new database to deal with the optPrefix issue too !

[Geolim4]

Here is the documentation to help you to create then register a new driver:

https://github.com/PHPSocialNetwork/phpfastcache/wiki/%5BV7%CB%96%5D-Override-a-core-driver-%7C-Setup-a-custom-driver

You can extends the 3 classes and just override DriverClear() :)