Ayende @ Rahien

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 20 Mar 2013 07:58:46 GMT

Richard, This is part of the 2.5 branch, and it is available here under the unstable builds: http://hibernatingrhinos.com/builds/ravendb-unstable-v2.5

Richard commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 20 Mar 2013 07:27:53 GMT

When will this feature be released? I cant find an actual build containing it.

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Fri, 15 Mar 2013 04:09:47 GMT

Configurator, Because there is no query.Advanced. This is implemented as a single stream request from the server. The enumerator has to be disposed, yes. If you stop reading, you need to dispose the connection, which will stop it on the server. It doesn't have a heavy impact, beyond the usual cost of having to access all of that data.

configurator commented on RavenDB’s Querying Streaming: Unbounded results

Thu, 14 Mar 2013 22:34:43 GMT

Why session.Advanced.Stream(query) and not query.Advanced.Stream()? Also, how is this actually implemented? Specifically, I'm interested in the finer details such as what happens if I stop reading halfway through, and whether or not the IEnumerator needs to be disposed when enumeration is finished. And whether this sort of query has a large impact on server performance because it takes a snapshot of the data.

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Thu, 14 Mar 2013 04:56:02 GMT

Lev, No, there isn't.

Lev Gorodinski commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 22:25:41 GMT

Is there a way to "freeze" results with the 2261 Client API if paging is used to retrieve very large subsets?

Daniel Schilling commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 13:44:11 GMT

Power users will realize it is trivial to us the `yield` keyword to turn this `IEnumerator` into an `IEnumerable`, if that's what they need.

Mouhong commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 07:13:08 GMT

@Ayende, Yea, you're right. But anyway, I can accept that the Stream() returns an enumerator. In my usage, I often don't need to do in memory filtering (can be done before calling Stream) or processing in this case. If I have a way to retrieve all records, it's already very good and enought. :p

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 06:56:09 GMT

Mouhong, That is a very true statement. In practice, it isn't really true. Sure it would be the user's fault. But the problem would typically still be blamed on RavenDB. If he goes and uses TakeAllAsList(), this is not just blindly calling ToList() and not noticing the implications, this is an explicit decision. We like to think of our API as a safety net, not a straitjacket. But you can go and check the number of times Linq delayed eval caused problems, and the number of times a ToList() caused even more problems...

Mouhong commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 06:52:13 GMT

@Ayende, If he use this to fix the "bug": session.Advanced.Stream(session.Query()).ToList(); /// Fix RavenDB Bug That's his problem, he should learn from the server carshing (if it crashed). There's no ideal solution. Just like Daniel said, if he found that he can't use Stream().ToList(), he would search google and finally found Daniel's TakeAllAsList(). So I think limit Stream api will mostly make "power users" feel inconvenient. It can't stop newbies from using TakeAllAsList()

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 06:31:11 GMT

Mouhong, Or, what is likely to happen. A user will search for this. And change: session.Query().ToList() To: session.Advanced.Stream(session.Query()).ToList(); /// Fix RavenDB Bug without ever doing any actual thinking whatsoever.

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 06:30:05 GMT

Daniel, One of the things that we are trying to do in the API is to have no easy pitfalls that will kill you. This API is really easy if you want to do streaming, as in push them to a file / network / process all of them one at a time. It is slightly hard if you want to get them all in memory. This is by design.

Mouhong commented on RavenDB’s Querying Streaming: Unbounded results

Wed, 13 Mar 2013 05:30:41 GMT

I agree with Daniel. If one doesn't know what he is doing, he won't use the Stream api, but use the Query<>().ToList(). But that is safe by default. If one knows that there's a Stream() api, he must know what he wants to do, so no need to limit him so much

Daniel Lang commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 22:05:49 GMT

I find it kind of sad that I can now replace my TakeAllAsList() extension method with another one that runs an iterator to populate a list. I would have preferred to have IEnumerable on which I can just call ToList(). There are power users who know what they're doing and who are just fine having all of the documents in memory. Now that we aren't limited by the size of http messages, I think we should really have a simple IEnumerable and let the users decide what to do with them.

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 18:07:22 GMT

Dan, This will NOT lock the database in any way.

Ayende Rahien commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 18:07:11 GMT

Yuriy, Because it is very easy to do a .ToList() on IEnumerable, which will force the entire thing to go into memory.

Dan commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 16:54:08 GMT

Will this lock the database or cause writes to be queued as long as the export is running?

Yuriy commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 16:04:50 GMT

Just out of curiosity - why not return IEnumerable?

Brian Vallelunga commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 15:30:36 GMT

Thanks. This will be very useful for the times when people want me to "export everything to a spreadsheet."

njy commented on RavenDB’s Querying Streaming: Unbounded results

Tue, 12 Mar 2013 13:34:28 GMT

Pretty darn good approach, very well done