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Posted to user-zh@flink.apache.org by 郑 洁锋 <zj...@hotmail.com> on 2020/01/06 08:59:06 UTC
Using async io in cep
Hi，
Is there a way to use asynchronous io to query the database in the process of cep?
________________________________
zjfplayer@hotmail.com
Re: Using async io in cep
Posted by Dawid Wysakowicz <dw...@apache.org>.
If I am not mistaken, my previous answer is still valid. There is no way
to have true asynchronicity within CEP conditions.
Why do you want to use async io there? Did you hit performance issues?
If so, you could try increasing the parallelism.
Best,
Dawid
On 07/01/2020 02:47, 郑 洁锋 wrote:
> Hi，
> Our business is to dynamically query (such as left join/right
> join) the mysql / oracle database during the cep process, or is there
> any other way to achieve this function?
>
> ------------------------------------------------------------------------
> zjfplayer@hotmail.com
>
>
> *From:* Dawid Wysakowicz <ma...@apache.org>
> *Date:* 2020-01-06 18:09
> *To:* 郑 洁锋 <ma...@hotmail.com>; user
> <ma...@flink.apache.org>
> *Subject:* Re: Using async io in cep
>
> Hi,
>
> You cannot use the Async IO as described here[1] in the CEP
> library, if that's what you are asking for.
>
> It is also not that straightforward to say what would an async
> processing in that case mean. Primary use case for Async IO is to
> execute parallel computations of independent data. In case of CEP
> it does not stand for processing of records within a single key,
> as those assume strict ordering and in general case depend on
> results of processing previous records. One could think of
> asynchronous processing of records from different keys in a single
> parallel instance, but that would require a careful key
> processing. If I am not mistaken Async IO also does not support a
> stateful processing on a keyed stream.
>
> Best,
>
> Dawid
>
> [1]
> https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/operators/asyncio.html
>
> On 06/01/2020 09:59, 郑 洁锋 wrote:
>> Hi，
>> Is there a way to use asynchronous io to query the
>> database in the process of cep?
>>
>> ------------------------------------------------------------------------
>> zjfplayer@hotmail.com
>>
>>
Re: Re: Using async io in cep
Posted by 郑 洁锋 <zj...@hotmail.com>.
Hi，
Our business is to dynamically query (such as left join/right join) the mysql / oracle database during the cep process, or is there any other way to achieve this function?
________________________________
zjfplayer@hotmail.com
From: Dawid Wysakowicz<ma...@apache.org>
Date: 2020-01-06 18:09
To: 郑 洁锋<ma...@hotmail.com>; user<ma...@flink.apache.org>
Subject: Re: Using async io in cep
Hi,
You cannot use the Async IO as described here[1] in the CEP library, if that's what you are asking for.
It is also not that straightforward to say what would an async processing in that case mean. Primary use case for Async IO is to execute parallel computations of independent data. In case of CEP it does not stand for processing of records within a single key, as those assume strict ordering and in general case depend on results of processing previous records. One could think of asynchronous processing of records from different keys in a single parallel instance, but that would require a careful key processing. If I am not mistaken Async IO also does not support a stateful processing on a keyed stream.
Best,
Dawid
[1] https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/operators/asyncio.html
On 06/01/2020 09:59, 郑 洁锋 wrote:
Hi，
Is there a way to use asynchronous io to query the database in the process of cep?
________________________________
zjfplayer@hotmail.com<ma...@hotmail.com>
Re: Using async io in cep
Posted by Dawid Wysakowicz <dw...@apache.org>.
Hi,
You cannot use the Async IO as described here[1] in the CEP library, if
that's what you are asking for.
It is also not that straightforward to say what would an async
processing in that case mean. Primary use case for Async IO is to
execute parallel computations of independent data. In case of CEP it
does not stand for processing of records within a single key, as those
assume strict ordering and in general case depend on results of
processing previous records. One could think of asynchronous processing
of records from different keys in a single parallel instance, but that
would require a careful key processing. If I am not mistaken Async IO
also does not support a stateful processing on a keyed stream.
Best,
Dawid
[1]
https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/operators/asyncio.html
On 06/01/2020 09:59, 郑 洁锋 wrote:
> Hi，
> Is there a way to use asynchronous io to query the database in
> the process of cep?
>
> ------------------------------------------------------------------------
> zjfplayer@hotmail.com
>
>