Ignite SQL function questions

[Ray <ra...@cisco.com>]

I've been reading Ignite official document and going through Ignite source
code for a few while now.

From the source code I see that Ignite can be a key/value store and the data
is stored in a ConcurrentHashMap for every partition.
So this is one copy of data in memory.

For Ignite SQL function, it seems like Ignite creates a H2 table in memory
based on the fields user want to be query with SQL.
So does it mean for every key with @QuerySqlField annotation, there will be
two copies of data in memory(one in ConcurrentHashMap and one in in-memory
H2 table)?








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Sent from: http://apache-ignite-users.70518.x6.nabble.com/

Re: Ignite SQL function questions

[Denis Magda <dm...@apache.org>]

There is always one copy stored in Ignite. 

The key-value store keeps data and Ignite indexes it using B+trees. H2 calls Ignite’s trees when prepares execution plans.

This is partially mentioned here [1] and there [2] you can read more about the memory architecture.

[1] https://apacheignite.readme.io/docs/sql-queries#section-how-sql-queries-work
[2] https://apacheignite.readme.io/docs/memory-architecture <https://apacheignite.readme.io/docs/memory-architecture>

—
Denis
 
> On Oct 11, 2017, at 12:21 AM, Ray <ra...@cisco.com> wrote:
> 
> I've been reading Ignite official document and going through Ignite source
> code for a few while now.
> 
> From the source code I see that Ignite can be a key/value store and the data
> is stored in a ConcurrentHashMap for every partition.
> So this is one copy of data in memory.
> 
> For Ignite SQL function, it seems like Ignite creates a H2 table in memory
> based on the fields user want to be query with SQL.
> So does it mean for every key with @QuerySqlField annotation, there will be
> two copies of data in memory(one in ConcurrentHashMap and one in in-memory
> H2 table)?
> 
> 
> 
> 
> 
> 
> 
> 
> --
> Sent from: http://apache-ignite-users.70518.x6.nabble.com/