Storing Null In Cache

[kellerjmrtn]

According to PSR-16 (which Illuminate\Cache\Repository implements)

Cache Misses - A cache miss will return null and therefore detecting if one stored null is not possible. This is the main deviation from PSR-6's assumptions.

If a null value is fundamentally indistinguishable from simply not setting the value at all, is there any reason to set a null value? For example (using Redis store, for example)

Cache::set('some_null_value', null);

// In Redis

127.0.0.1:6379[1]> keys *
1) "my_cache_prefix:some_null_value"

127.0.0.1:6379[1]> get "my_cache_prefix:some_null_value"
"N;"

Despite the key physically being set in Redis, it's seemingly indistinguishable from a key that was never set:

Cache::get('some_null_value'); // null
Cache::has('some_null_value'); // false

// But also

Cache::get('some_value_that_was_never_set'); // null
Cache::has('some_value_that_was_never_set'); // false

Therefore, does it even make sense to set a null value in cache in the first place? Admittedly I don't know implementation specifics, so it's possible not doing so could cause some undesired behavior somewhere that I'm unaware of. But it seems like avoiding setting null could potentially have a few (minor) performance benefits:

1. Save a bit of storage space in cache (especially if this happens repeatedly)
2. Save an extra write operation on put, remember, etc

Suggested Change

Since Illuminate\Cache\Repository does set a real key/value pair in cache when the value is null, I'm suggesting/wondering whether it makes sense to update that implementation to simply not set the key/value pair at all

[henzeb]

I'd go with Cache:;get('key')?:null. I completely agree with you...