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From Ufuk Celebi <...@apache.org>
Subject Re: Queryable State max number of clients
Date Mon, 14 Aug 2017 20:17:26 GMT
This is as Aljoscha describes. Each thread can handle many different
clients at the same time. You shouldn't need to change the defaults in
most cases.

The network threads handle the TCP connections and dispatch query
tasks to the query threads which do the actual querying of the state
backend. In case of the RocksDB backend for example this might involve
blocking I/O calls.

– Ufuk

On Mon, Aug 14, 2017 at 12:35 PM, Aljoscha Krettek <aljoscha@apache.org> wrote:
> Hi,
>
> I think the number of network treads and number of query threads only
> roughly correlate with the number of clients that can query in parallel
> since this is using asynchronous communication via Akka/Netty. Of course,
> increasing that number means there can be more connections but I think even
> just 1 Thread or each of those should be able to easily handle multiple
> queries at the same time.
>
> I'm cc'ing Ufuk and Kostas who might know more about this.
>
> Best,
> Aljoscha
>
> On 9. Aug 2017, at 17:19, Ziyad Muhammed <mmziyad@gmail.com> wrote:
>
> Hi all,
>
> I'm trying to understand how many parallel clients will be supported by the
> queryable state.
>
> query.server.network-threads: number of network (event loop) threads for the
> KvStateServer (0 => #slots)
> query.server.query-threads: number of asynchronous query threads for the
> KvStateServerHandler (0 => #slots).
>
> so, if I choose 0 for both these parameters, what will be the maximum number
> of parallel clients supported?
>
> I tried more parallel clients than number of slots, but all of them were
> able to query the state in parallel. Can someone help me to understand the
> logic here?
>
> Thanks in advance.
>
> Best
> Ziyad
>
>

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