Hi,

The only way that I can think of is if you keep your flatMap operator with 
parallelism 1, but that might defeat the purpose. Otherwise there is no way to 
open one single connection and share it across multiple TaskManagers (which can 
be running on different physical machines). Please rethink your 
solution/approach with respect to distributed nature of Flink.

However there are some valid use cases where one would like to have some part 
of his job graph distributed and some part(s) non distributed - like issuing 
one single commit after a distributed write, or processing a data in parallel 
but writing them to a relational database like MySQL via one single Sink 
operator.. 

Piotrek

> On 26 Apr 2018, at 15:23, Soheil Pourbafrani <soheil.i...@gmail.com> wrote:
> 
> Here is my code 
> 
> stream.flatMap(new FlatMapFunction<byte[], Void>() {
> 
>     @Override
>     public void flatMap(byte[] value, Collector<Void> out) throws Exception {
>         Parser.setInsert(true);
>         CassandraConnection.connect();
>         Parser.setInsert(true);
>         System.out.println("\n*********** New Message ***********\n");
>         System.out.println("Row Number : " + i ++ );
>         System.out.println("Message    : " + HexUtiles.bytesToHex(value));
>         Parser.parse(ByteBuffer.wrap(value), ConfigHashMap);
>     }
> });
> 
> 
> On Thu, Apr 26, 2018 at 5:22 PM, Soheil Pourbafrani <soheil.i...@gmail.com 
> <mailto:soheil.i...@gmail.com>> wrote:
> I want to use Cassandra native connection (Not Flink Cassandra connection) to 
> insert some data into Cassandra. According to the design of the code, the 
> connection to Cassandra will open once at the start and all taskmanager use 
> it to write data.  It's ok running in local mode.
> 
> The problem is when I submit the code on YARN cluster, as each taskmanager 
> has it's own JVM, the connection to the Cassandra will not share and I should 
> open and close it for each taskmanager. Is there any way to have a connection 
> for all taskmanagers?
> 

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