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From Lars Francke <>
Subject Re: Maximum attribute size
Date Wed, 17 Feb 2016 23:47:33 GMT
Thanks a lot for confirming my suspicions.

One last clarification: The WAL is different from the swapping concept,
correct? I guess it's way faster to swap in a dedicated "dump" than
replaying a WAL.

On Wed, Feb 17, 2016 at 7:53 PM, Joe Witt <> wrote:

> Lars,
> You are right about the thought process.  We've never provided solid
> guidance here but we should.  It is definitely the case that flow file
> content is streamed to and from the underlying repository and the only
> way to access it is through that API.  Thus well behaved extensions
> and the framework itself can handle basically data as large as the
> underlying repository has space for.  For the flow file attributes
> though these are held in memory in a map with each flowfile object.
> So it is important to avoid having vast (undefined) quantities of
> attributes or attributes with really large (undefined) values.
> There are things we can and should do to make even this relatively
> transparent to the users and it is why actually we support swapping
> flowfiles to disk when there are large queues because even those inmem
> attributes can really add up.
> Thanks
> Joe
> On Wed, Feb 17, 2016 at 11:06 AM, Lars Francke <>
> wrote:
> > Hi and sorry for all these questions.
> >
> > I know that FlowFile content is persisted to the content_repository and
> can
> > handle reasonably large amounts of data. Is the same true for attributes?
> >
> > I download JSON files (up to 200kb I'd say) and I want to insert them as
> > they are into a PostgreSQL JSONB column. I'd love to use the PutSQL
> > processor for that but it requires parameters in attributes.
> >
> > I have a feeling that putting large objects in attributes is a bad idea?

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