You are viewing a plain text version of this content. The canonical link for it is here.

Posted to user@ignite.apache.org by ctranxuan <ce...@streamdata.io> on 2017/03/31 13:57:01 UTC

Can a Continuous Queries miss some updates order?

Hi,
We are testing Apache Ignite Continuous Queries and during the tests, we
have noticed that some continuous queries misses some updates of the cache.
Our use case is the following one:

- we have a feeder (that is part of the server nodes) and that feeds 1000
caches with data every seconds
- we have a client program (that is part of the server nodes) that opens
1000 continuous queries, 1 continuous query per cache
So, some of these continuous queries gets from times to times few updates of
the cache in the wrong order (i.e. in an order that is different from the
order the items have been pushed in the cache). We were wondering whether
the fact that a continuous query gets updates of the cache in a wrong order
was "normal".

We have also performed the test with 500, 250, 100 caches and have the same
results.

Besides, we are also wondering how many caches and continuous queries can be
created? Does Apache Ignite support hundred thousands of creation of caches
and continuous queries?

The code for the tests can be found there:
https://github.com/ctranxuan/ignite-cq-bench-parent
We use Ignite 1.9.0.

Thanks in advance for the answers!



--
View this message in context: http://apache-ignite-users.70518.x6.nabble.com/Can-a-Continuous-Queries-miss-some-updates-order-tp11620.html
Sent from the Apache Ignite Users mailing list archive at Nabble.com.

Re: Can a Continuous Queries miss some updates order?

Posted by ctranxuan <ce...@streamdata.io>.

Thanks for the reply and answering all of our questions!




--
View this message in context: http://apache-ignite-users.70518.x6.nabble.com/Can-a-Continuous-Queries-miss-some-updates-order-tp11620p11623.html
Sent from the Apache Ignite Users mailing list archive at Nabble.com.

Re: Can a Continuous Queries miss some updates order?

Posted by Nikolai Tikhonov <nt...@apache.org>.

Hi,

Continuous Query (CQ) garanties that the order for events will be preserved
per entry. For example:

cache.put(key1, 100);
cache.put(key2, 100);
cache.put(key1, 200);
cache.put(key2, 200);

CQ guarantees that for key1 events will be received in the following order
(1, 100) --> (1, 200) but you can got event for key2 early than for key1.
Ignite doesn't have limitation on count of caches and CQ.

On Fri, Mar 31, 2017 at 4:57 PM, ctranxuan <ce...@streamdata.io>
wrote:

> Hi,
> We are testing Apache Ignite Continuous Queries and during the tests, we
> have noticed that some continuous queries misses some updates of the cache.
> Our use case is the following one:
>
> - we have a feeder (that is part of the server nodes) and that feeds 1000
> caches with data every seconds
> - we have a client program (that is part of the server nodes) that opens
> 1000 continuous queries, 1 continuous query per cache
> So, some of these continuous queries gets from times to times few updates
> of
> the cache in the wrong order (i.e. in an order that is different from the
> order the items have been pushed in the cache). We were wondering whether
> the fact that a continuous query gets updates of the cache in a wrong order
> was "normal".
>
> We have also performed the test with 500, 250, 100 caches and have the same
> results.
>
> Besides, we are also wondering how many caches and continuous queries can
> be
> created? Does Apache Ignite support hundred thousands of creation of caches
> and continuous queries?
>
> The code for the tests can be found there:
> https://github.com/ctranxuan/ignite-cq-bench-parent
> We use Ignite 1.9.0.
>
> Thanks in advance for the answers!
>
>
>
> --
> View this message in context: http://apache-ignite-users.
> 70518.x6.nabble.com/Can-a-Continuous-Queries-miss-some-
> updates-order-tp11620.html
> Sent from the Apache Ignite Users mailing list archive at Nabble.com.
>