Redis StackExchange cache performance

Question

I am trying the Redis StackExchange change provider with Azure and just wondering on the best setup.

Considering the following code

private static ConnectionMultiplexer connection = ConnectionMultiplexer.Connect(...);

public string Get(string key)
{
    IDatabase cache = connection.GetDatabase();
    return cache.StringGet(key);
}

Is the getting of the database going to be a performance hit calling it each time a call to the cache is made?

Should it be managed some way else?

Should it just be created for the lifetime of the object but not static?

What is best practice around managing the IDatabase?

Sen Jacob · Accepted Answer · 2018-06-14 08:49:40Z

6

Is the getting of the database going to be a performance hit calling it each time a call to the cache is made?

Not noticeably so; as described here:

The object returned from GetDatabase is a cheap pass-thru object, and does not need to be stored.

Of course, you can choose to store it, if you so wish. As it happens, we do that - but that is simply because we use different database numbers (for different sites), and it is just as convenient to store an IDatabase as it is to store the int that represents the database number.

Other than that, though, you don't need to worry too much - if you allocate on-demand, it will still be very cheap to collect etc.

The only other thing worth saying is that it may be worth caching in-memory before you touch redis: a redis call is fast, but a redis call that you don't make is faster.

edited Jun 14, 2018 at 8:49

Sen Jacob

3,4703 gold badges37 silver badges66 bronze badges

answered Jun 24, 2014 at 11:37

Marc Gravell

1.1m273 gold badges2.6k silver badges3k bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Craig Over a year ago

"The only other thing worth saying is that it may be worth caching in-memory before you touch redis: a redis call is fast, but a redis call that you don't make is faster." I assume by this you mean that once you make a call to the cache then store the value in memory, possibly just for the life of the request, but it could make a difference. Otherwise how do you handle invalidation of the in-memory across servers?

Marc Gravell Over a year ago

@Craig ideally, longer than the request; when invalidation matters: pub/sub; actually, recent versions of redis optionally include keyspace change notifications, but that needs to be enabled at the server; we just use regular explicit pub/sub when we need invalidation (our "set value" method has a bool broadcastInvalidation = false, if you see what I mean)

Craig Over a year ago

Nice. Do you have any examples of your broadcastInvalidation implementation?

Collectives™ on Stack Overflow

Redis StackExchange cache performance

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related