Re: Why ListState of flink don't support update?

[Stefan Richter]

Hi,

this is because the list state is intended to be append only. The underlying 
reason is that this allows certain optimizations in the underlying 
datastructures. For example, a list state for the RocksDB backend can make use 
of RocksDB’s merge operator and does not require a full rewrite to the DB on 
appends.

If you need to have a list that supports this, you could use a value state of 
type list or use a map state where you map from list-index -> element.

Best,
Stefan

> Am 17.08.2017 um 06:07 schrieb yunfan123 :
> 
> If I want to update the list.
> I have to do two steps:
> listState.clear()
> for (Element e : myList) {
>listState.add(e);
> }
> 
> Why not I update the state by:
> listState.update(myList) ?
> 
> 
> 
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Why ListState of flink don't support update?

[yunfan123]

If I want to update the list.
I have to do two steps:
listState.clear()
for (Element e : myList) {
listState.add(e);
}

Why not I update the state by:
listState.update(myList) ?



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http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Why-ListState-of-flink-don-t-support-update-tp14957.html
Sent from the Apache Flink User Mailing List archive. mailing list archive at 
Nabble.com.