Github user spdrnl commented on the pull request:
https://github.com/apache/flink/pull/1640#issuecomment-189210134
In some circumstances it is possible to make writes to Cassandra
idempotent, by adding an unique id to the insert. See the example below.
Counters are probably different in this though.
```
cqlsh:mykeyspace> CREATE TABLE IF NOT EXISTS timeline (
eid uuid,
timesegment bigint,
from_url text,
to_url text,
PRIMARY KEY ((timesegment) , eid));
cqlsh:mykeyspace> INSERT INTO timeline (eid, timesegment, from_url, to_url)
VALUES(50554d6e-29bb-11e5-b345-feff819cdc9f, 1, 'a', 'b') ;
cqlsh:mykeyspace> SELECT * FROM timeline;
timesegment | eid | from_url | to_url
-------------+--------------------------------------+----------+--------
1 | 50554d6e-29bb-11e5-b345-feff819cdc9f | a | b
(1 rows)
cqlsh:mykeyspace> INSERT INTO timeline (eid, timesegment, from_url, to_url)
VALUES(50554d6e-29bb-11e5-b345-feff819cdc9f, 1, 'a', 'b') ;
cqlsh:mykeyspace> SELECT * FROM timeline;
timesegment | eid | from_url | to_url
-------------+--------------------------------------+----------+--------
1 | 50554d6e-29bb-11e5-b345-feff819cdc9f | a | b
(1 rows)
cqlsh:mykeyspace> INSERT INTO timeline (eid, timesegment, from_url, to_url)
VALUES(uuid(), 1, 'a', 'b') ;
cqlsh:mykeyspace> SELECT * FROM timeline;
timesegment | eid | from_url | to_url
-------------+--------------------------------------+----------+--------
1 | 50554d6e-29bb-11e5-b345-feff819cdc9f | a | b
1 | 35761e5e-06b3-4ce6-9038-c9014e498281 | a | b
```
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