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From "Vladimir St." <vlads...@yandex.ru>
Subject Re: Distributed query is too slow.
Date Thu, 02 Feb 2017 17:06:42 GMT
Hi Dmitry. Thanks for the answer.

dkarachentsev wrote
> When you run test on single node it works just locally, without node
> communication overhead. Good point will be to test on client node. In that
> case, even with one server node, query will be sent over network with all
> that communication stuff. Also, if cache is REPLICATED, query always will
> be invoked locally, or, if you query from client - sent to only one node.

If I'm correct, the search is always local. Any node searches only its local
data. In case of partitioned cache the results are afterwards merged within
shared transaction scope. That's why I've tried splitting and reducing query
results manually.

dkarachentsev wrote
> here is my results:
> 10_000 records (request one-by-one), 
> 1 node: 445ms
> 2 nodes: 512ms
> 3 nodes: 696ms
> 4 nodes: 839ms

Your timings are of some sort I expected but didn't get. Of course, there
will be some communication costs when we run on several nodes, especially in
network. But they souldn't be so huge as in my case.

Here is my results for 10 000 records on same machine:

1 node: 391ms
2 nodes:  1470ms
3 nodes: 1689ms
4 nodes: 2223ms

There is a very large gap between one and two nodes, i.e. when the
partitioning really appears.

Can the problem grow from Ignite settings, not cache settings?

How do you run your test? My scenario:
-	First node starts and acquires the cache.
-	Then it sees that the cache is empty and fills it with n records
-	After, the node prepares a list of known-params (fields) to search for
-	Runs through this list and executes the query
-	When first (previous) node is done, I launch next one
-	Next node does the same except filling the cache.

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