Function
| Arg | Description | Type |
|---|---|---|
| func | A function to evaluate | LazyExpr (required) |
| name | The global name of this cache (needed when more than one) | string |
| key | Cache key to use. | string (required) |
| period | The latest age of the cache. | int64 |
Creates a cache object.
A Cache is a data structure which is used to speed up calculating data by keeping it’s value in memory. A cache is essentially a key value store - when the key is accessed, the function will be calculated producing a value. If the key is accessed again, the value is returned from the cache without calculating it again.
For example consider the following:
LET get_pid_query(Lpid) =
SELECT Pid, Ppid, Name FROM pslist(pid=Lpid)
SELECT cache(func=get_pid_query(Lpid=Pid), key=str(str=Pid))
FROM ....
The cache will ensure that get_pid_query() is only called once per unique Pid by comparing the key against the internal memory store.