Bring back igbinary support
I just realized that php-redis in Ubuntu 18.04 has a dependency on php-igbinary.
This made me wonder because I remember it was used in the past in the caching framework but got removed again later:
The changelog for the removal commit says:
[TASK] Remove igbinary from cache framework The patch removes igbinary serializer support from the cache framework. When igbinary support was added back then in PHP 5.3 times, it had the potential to serialize data quicker than the default serializer. Unfortunately, other promises aren't held: * The module found no general acceptance within the PHP community and isn't supported very well. PHP 7 is still not officially supported. * Last release at the time of this writing was in 2014-08 * The module must still be compiled from source and no recent distribution ever packaged it by default * The maintenance load on devOps side is high: The module must be recompiled with each minor php release * In case the module is not updated, it throws errors at a central place of the system and can easily brick a whole instance * The module found no huge acceptance by hosters and is only very rarely used in real life instances * A performance impact is only measurable in very small and highly specialized use cases, it typically plays no role in casual frontend or backend requests. We've seen several life systems in the wild lately with sloppy hosters not maintaining the igbinary module within their infrastructure properly. The current implementation with VariableFrontend dynamically detecting and then force using the module leads to hard crashes in those situations. The main issue is that serializing is done via PHPs serializer and unserializing using igbinary then fails, effectively rendering the entire installation bricked. To come by those situations, it is considered more important to deliver a stable product than a product that is quicker in more theoretical use cases. Thus, the support for this module is kicked from the standard cache frontend. In case igbinary still gives significant boost for specialized specific instances, an admin can still configure a VariableFrontend that uses this serializer.
As it looks to me, this is no longer valid, and the module is actively improved:
Also, it is now required by php-redis:
- see changelog above at version 3.1.1
- Ubuntu 18.04 package: https://launchpad.net/ubuntu/bionic/+source/php-redis
Therefore I suggest to check again if the situation has changed and if php-igbinary support should be added (with a configuration flag?) again.
Updated by Mathias Schreiber over 1 year ago
I'm not a pro in PHP internals but to me it looks like it is an option in the php redis module.
It reads to me (and I could be wrong) that if the igbinary module is there, then it's a dependency.
So it's about balancing risk and reward.
The risks have been outlined in the original commit - I consider the risk "high" because the error is very hard to track down and renders an entire install bricked.
I did several tests back then testing out the reward (aka the increase in speed) and it used to be a single digit improvement - and even that was when I created unrealistic scenarios with thousands of records being serialized and unserialized.
The team collectively decided that these usecases are very edgy and might (positively) affect a very low number of installations.
That's the current state, so far, so good.
Neither Christian or me can make this a priority at the moment, so if someone wants to step in and run tests to determine the reward of bringing back igbinary as well as taking over the time-critical fixing in case issues or regressions show up, I don't object to bringing igbinary back.