That is a great idea.
Thanks.
Denis
Le 27/07/2015 16:54, John Reilly a écrit :
Another approach you could take is to create the table at the time
that you create the topology rather than have the topology create it.
On Mon, Jul 27, 2015 at 05:41 Nathan Leung <[email protected]
<mailto:[email protected]>> wrote:
Using task id is a good idea. I don't recall if 0 or 1 is the
lowest, but it's probably a good to use the lowest possible one
for intialization, just in case you ever run a topology with only
1 bolt.
On Mon, Jul 27, 2015 at 8:02 AM, Denis DEBARBIEUX
<[email protected] <mailto:[email protected]>> wrote:
Dear all,
I am writting a bolt. It is in charge of saving information in
some database (cassandra). In its prepare method, I am
creating the table (CQL query like CREATE TABLE IF NOT EXISTS
...).
When I run my topology with many workers, I got a concurrent
access exception. Indeed, all my workers are creating the same
table at the same time. How to avoid this?
My first idea is to elect one worker (e.g. base on the taskId)
that will create the table. Other worker will wait until the
job is done. Is it a good design?
Thanks for your help.
Denis
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