It’s definitely possible, but it would be a fair amount of work on your part.
The class JavaRowFormat already describes how rows are represented within
generated code, and it already has a value LIST.
Now, FilterableTable is slightly different. It has to produce rows in Object[]
format. Why? Because it (and ScannableTable and ProjectableFilterableTable) is
intentionally a simple API.
If you have more complex requirements, you should use QueryableTable. See
EnumerableTableScan.deduceElementType():
public static Class deduceElementType(Table table) {
if (table instanceof QueryableTable) {
final QueryableTable queryableTable = (QueryableTable) table;
final Type type = queryableTable.getElementType();
if (type instanceof Class) {
return (Class) type;
} else {
return Object[].class;
}
} else if (table instanceof ScannableTable
|| table instanceof FilterableTable
|| table instanceof ProjectableFilterableTable
|| table instanceof StreamableTable) {
return Object[].class;
} else {
return Object.class;
}
}
Then you will need to decide whether rows remain as List all the way through
the pipeline or whether you convert them to Object[] at some point.
Julian
> On Jan 13, 2017, at 1:38 AM, Leur, Maxime <maxime.l...@fisglobal.com> wrote:
>
> Hi all,
>
> First thanks for your project, it is very great and help me a lot to provide
> SQL interface to own internal DB.
> I succeed to implement my own Schema/Table with the tutorial but I have
> performance issues on high volume.
>
> I mean when I have 1 millions of rows with many columns (> 20), it takes too
> long time to execute request.
> I check the code and I think that is due to the fact that I must convert my
> internal object (row) to “Object[]”
> (org.apache.calcite.schema.FilterableTable).
>
> It is possible to give a Map / List or any proxy Object to “Apache Calcite”
> instead of “Object[]” array?
> I check some Table implementation on GitHub (MongoDB, Cassandra) and debug
> code in Eclipse but I do not succeed.
> I think that is linked to
> “org.apache.calcite.adapter.java.AbstractQueryableTable” but despite all my
> efforts I cannot understand how to do it.
>
> Could you please help me on that subject?
>
> Regards,
>
> Maxime Leur
> J2EE Architect
> Global Trading / TCC
> T: +33 (0)1 53 40 57 46
> C: 1746
> E: maxime.l...@fisglobal.com <mailto:maxime.l...@fisglobal.com>
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