How to get multiple records with XRange in redis stream efficiently

Question

Looking at Redis streams and building indexes on a stream ( like EventStore does) , this works pretty well and i can get a bunch of entries in a stream except i cant find a nice way to return all the records by id eg like an MGET. This is a simplified version of what im looking at.

        var records = await conn.StreamRangeAsync(indexStreamName, nextPosition, null, BatchSize);
        if (records.Any())
        {
             var results = new List<Event>();
             foreach (var record  in records)
             {
                  var msgs = await conn.StreamRangeAsync(record.Values.FirstOrDefault(x => x.Name == "stream").Value.ToString(), record.Values.FirstOrDefault(x => x.Name == "key").Value, null, 1);
                        results.Add(ToEvent(msgs.First()));
              }
              await playEvents(results.ToArray());
        }

Obviously this is very inefficient and i was wondering is there some way to get this from the server in 1 request.

I also considered streams building other streams however it will result in message duplication and our messages can get large. Yes i could than put all messages in a set but 2 levels of indirection is a bridge too far.

score 0 · Answer 1 · answered May 21 '20 at 23:37

0

Still hoping for a better answer but one way you can do this is

Is have the messages in a parent stream and all the indexes being smaller streams not ideal since the larger stream is logically an aggregation and not the real data but will work ok.

answered May 21 '20 at 23:37

user1496062

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How to get multiple records with XRange in redis stream efficiently

1 Answers1