redispipelinestackexchange.redisbatching

StackExchange.Redis: Batch access for multiple hashes

So I need to access in bulk many different hashes (in StackExchange.Redis, I have different RedisKey's).

What is the best (fastest) way to do it? For example, for these two possible implementations, is either correct? Which one works better?

1.

List<Task<HashEntry[]>> list = new List<Task<HashEntry[]>>();
List<RedisKey> keys; //Previously initialized list of keys
foreach (var key in keys)
{
    var task = db.HashGetAllAsync(key);
    list.Add(task);
}
await Task.WhenAll(list);

List<Task<HashEntry[]>> list = new List<Task<HashEntry[]>>();
List<RedisKey> keys; //Previously initialized list of keys
IBatch batch = db.CreateBatch();
foreach (var key in keys)
{
    var task = batch.HashGetAllAsync(key);
    list.Add(task);
}
batch.Execute();
Solution

  • On performance: have you timed them?

    Other than that: both work, and have different trade-offs; the latter is synchronous, for example - bit benefits from avoiding all of the TPL overheads and complications. You might also want to consider a third option - a Lua script that accepts and array of keys as input and invokes HGETALL for each.