Thanks very much.  I got it. 

wangl...@geekplus.com.cn
 
From: Joe Witt
Date: 2019-10-16 17:24
To: users@nifi.apache.org
Subject: Re: Re: NiFi backpressure not work
Lei

Please do not post to both users and dev list.  Dropping dev.

Yes these scenarios are based on limitations of a given processor 
implementation or the nature of a given protocol/mechanism.  NiFi enforces back 
pressure by slowing/stopping scheduling a component and making fact of back 
pressure available to components.

I dont know about this particular processor but it likely needs to be updated 
so the max amount of data it will return in any one cycle is small enough or 
controllable enough to avoud what youre seeing.

Thanks
Joe

On Wed, Oct 16, 2019 at 3:06 AM wangl...@geekplus.com.cn 
<wangl...@geekplus.com.cn> wrote:
CaptureChangeMySQLSelf is  from CaptureChangeMySQL and I fix a small bug about 
binlog parsing. But i am sure there's no change that will affect the 
backpressure mechanism.

Actually I don't quite understand it. 
It is related with the implementation of the processor?  In order to use the 
backpressure mechanism, the processor must do something? 
In my case, what it will happen if the queue continue to grow(for example to 
100G)?  Something bad will happen?

Thanks,
Lei




wangl...@geekplus.com.cn
 
From: josef.zahn...@swisscom.com
Date: 2019-10-16 14:17
To: users@nifi.apache.org; d...@nifi.apache.org
Subject: Re: NiFi backpressure not work
Hi Lei
 
I assume it’s the same as for the ListSFTP. As I don’t know the 
CaptureChangeMySQLSelf processor I try to explain it for the ListSFTP. There 
with one single execution of the processor you get as much flowfiles as you 
have files on your disk. If it finds 1000 it sends out 1000 flowfiles. If it 
finds 1’000’000 it sends out 1’000’000 flowfiles. The processor can’t hold back 
some flows and knows nothing about your queue, so it sends out everything in 
one “batch” per execution – even if it is more than the queue size. Hope this 
explains the behavior a bit.
 
Cheers
 
 
From: "wangl...@geekplus.com.cn" <wangl...@geekplus.com.cn>
Reply to: "users@nifi.apache.org" <users@nifi.apache.org>
Date: Wednesday, 16 October 2019 at 08:10
To: users <users@nifi.apache.org>, dev <d...@nifi.apache.org>
Subject: NiFi backpressure not work
 
As the picture shows.
I have set the backpressure object threshold to 10000, but picture shows 
there's more than 1,000,000. Why this happens?
 
 
 
Thanks, Lei


wangl...@geekplus.com.cn

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