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Posted to commits@ignite.apache.org by vo...@apache.org on 2017/01/16 13:08:24 UTC
[10/18] ignite git commit: updated 'setCollocated' flag documentation
updated 'setCollocated' flag documentation
Project: http://git-wip-us.apache.org/repos/asf/ignite/repo
Commit: http://git-wip-us.apache.org/repos/asf/ignite/commit/1f358db1
Tree: http://git-wip-us.apache.org/repos/asf/ignite/tree/1f358db1
Diff: http://git-wip-us.apache.org/repos/asf/ignite/diff/1f358db1
Branch: refs/heads/ignite-2.0
Commit: 1f358db1eb3c9a28dd1a66042539796c1ef5ac45
Parents: ff0caf8
Author: Denis Magda <dm...@gridgain.com>
Authored: Wed Jan 11 13:43:39 2017 -0800
Committer: Denis Magda <dm...@gridgain.com>
Committed: Wed Jan 11 13:43:39 2017 -0800
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.../java/org/apache/ignite/cache/query/SqlFieldsQuery.java | 6 ++++++
1 file changed, 6 insertions(+)
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http://git-wip-us.apache.org/repos/asf/ignite/blob/1f358db1/modules/core/src/main/java/org/apache/ignite/cache/query/SqlFieldsQuery.java
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diff --git a/modules/core/src/main/java/org/apache/ignite/cache/query/SqlFieldsQuery.java b/modules/core/src/main/java/org/apache/ignite/cache/query/SqlFieldsQuery.java
index 9b17e78..eac8cfc 100644
--- a/modules/core/src/main/java/org/apache/ignite/cache/query/SqlFieldsQuery.java
+++ b/modules/core/src/main/java/org/apache/ignite/cache/query/SqlFieldsQuery.java
@@ -164,6 +164,12 @@ public class SqlFieldsQuery extends Query<List<?>> {
/**
* Sets flag defining if this query is collocated.
*
+ * Collocation flag is used for optimization purposes of queries with GROUP BY statements.
+ * Whenever Ignite executes a distributed query, it sends sub-queries to individual cluster members.
+ * If you know in advance that the elements of your query selection are collocated together on the same node and
+ * you group by collocated key (primary or affinity key), then Ignite can make significant performance and network
+ * optimizations by grouping data on remote nodes.
+ *
* @param collocated Flag value.
* @return {@code this} For chaining.
*/