[jira] [Created] (IGNITE-11928) keep data of same primary index on same node

["Ewan (JIRA)" <ji...@apache.org>]

Ewan created IGNITE-11928:
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             Summary: keep data of same primary index on same node
                 Key: IGNITE-11928
                 URL: https://issues.apache.org/jira/browse/IGNITE-11928
             Project: Ignite
          Issue Type: Wish
          Components: data structures, persistence
    Affects Versions: None
            Reporter: Ewan
             Fix For: None


I searched a lot and find very few documents talking about how does Ignite index and how it use indices. What i hope Ignite to have is something like the partition key in Cassandra, which is used by the database engine to find out which node in the cluster contains the row(s) of a table. Since the partition key determines the node where the rows with the same partition key stores, it will dramatically reduce the interaction between Ignite notes for a query, especially when the query is within the data of a specified partition key.

e.g. Table: profit of the companies by days, it has three columns:
day: primary key / partition key
company id: secondary key / column key
profit: value of the row

Query:
select * from table where day = '2019-01-01';

In Cassandra, the query will only touch one node to fetch all the data. The partition key has a prerequisite that the users or the programmers will ensure that all the data with same partition key will be small enough to be stored on one node of the cluster.

But in Ignite, for the same query, it may touch the whole cluster since each node in the cluster only stores a portion of the data with that primary key. This limits the performance of Ignite to be linearly increased when more nodes added to the cluster. I personally think the linear performance improvement is one of the key features a distributed database should have.

I would like to recommend that Ignite adds an option/setting for users to determine if all rows of same primary key to be stored on the same node. Thanks.

 



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