Records should be cached as arrays/serialized arrays?...or Dont cache at all?

phproy

Hi guys,

I was wondering if I shold use serialized arrays to cache records from my select statement or use plain array in PHP file? I see that some applications use serialized array to cache, why?

plain array:

$result = array(
'1'=>'blah',
'2'=>'blah4',
..................
)

And one more thing. When is it good not to read from cache, from a performance point of view?
As reading from the cache takes a little bit of resources, it is less resource hungry to SELECT from database when the returned recordset is small?

Shrike

You've picked the wrong forum but I'm sure a friendly mod will move the thread for you.

I don't see much difference between a serialized array and a non-serialized one. The first might make for a smaller file however it requires calls to serialize and unserialize for each request.

Why are you choosing to do result caching outside of the database. MySQL 4 has an in-built cache for this kind of thing. In your model how would you know when to not use the cache (short of querying the database again to see if anything had changed)?

Edit: having just read up about MySQL's cache it seems it is cleared when a modification is done on any of the tables used in the cache. So I suppose that the same could be employed in a roll-your-own system but I suspect it would be more beneficial performance wise to use the MySQL cache.

phproy

Well I am not sure when not to cache I just asked just in case. 😃
I am not sure of the amount of resources used to read file and query the database so I cant make an educated decision.

As to caching, I agree with you on nonserialized array. I prefer it that way as I also thought there is less resource usage due to the absence of the unserializing process.
I am using ADODB database abstraction and they are using serialized array to cache results so I was wondering why.

Anyway the reason why I am not using MYSQL's native caching is that I am using ADODB database abstraction layer. Not every database have some sort of caching . I need to do it in PHP in my case.