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https://issues.apache.org/jira/browse/NIFI-1626?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15195241#comment-15195241
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Matthew Clarke commented on NIFI-1626:
--------------------------------------

So i saw some discussions on line where people suggested breaking messages 
larger than 1MB in to multiple requests to zookeeper.  I saw nothing that said 
how to do this.  Feel like zookeeper set caps and said we will just fail fast 
if they are exceeded.  Good news is that i think we figured out the 
snapshot/transaction log rolling thing.  We need to set the snapCount and 
should probably add this to the zookeeper.properties file. If not set it 
defaults to 10,000 events.  We set it to 1,000 in our tests with listHDFS using 
"snapCount=1000". First couple logs rolled at ~129MB and then each after that 
got a larger and larger (my guess is because of the increasing size of the 
events).  So when a single event gets large, the transaction log size 
skyrockets.  Even when zookeepers fails, the transaction log still continues to 
record events (even the large ones of 1MB).  It too eventually fails.  Not sure 
what is the ultimate trigger there.

> ZooKeeper State Provider should block requests > 1 MB
> -----------------------------------------------------
>
>                 Key: NIFI-1626
>                 URL: https://issues.apache.org/jira/browse/NIFI-1626
>             Project: Apache NiFi
>          Issue Type: Bug
>          Components: Core Framework
>            Reporter: Mark Payne
>            Assignee: Mark Payne
>             Fix For: 0.6.0
>
>
> ZooKeeper does not support setting data on a ZNode to a value greater than 1 
> MB. However, the client doesn't does not check this - it sends the data to 
> the server and lets the server reject the request. This can cause problems 
> with ZooKeeper if the requests grow extremely large. As a result, we should 
> prevent this from ever happening by throwing an Exception ourselves if 
> attempting to set state to a value > 1 MB



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