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https://issues.apache.org/jira/browse/CALCITE-1304?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15358437#comment-15358437
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Kasper Sørensen commented on CALCITE-1304:
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The way I see it is that Calcite seems to have a more elaborate query API than
MetaModel. I'm not sure if it is entirely a superset of query features, but
mostly I think that any query construct in MetaModel more or less is also
available in Calcite. MetaModel has a less pluggable query API than Calcite,
but what it has is the same query language for all datastores, and we have been
attempting to optimize queries in MetaModel too, although it wasn't the primary
focus like in Calcite.
It presents a nice point though: If we can make a Calcite adaptor for the
generic query API of MetaModel, pushing down as much query logic as possible to
the uniform query of MetaModel, then it would perform as good as the MetaModel
adaptors are currently implemented. So from that perspective I think this is a
really good idea.
But in addition I think also that the MetaModel project should look at adopting
Calcite as it's query optimizer/engine rather than continuing with the current
inferior MetaModel query handler. We could do that maybe by introducing an
optional interface that MetaModel's adaptors could implement. If that interface
is implemented then Calcite will leverage it directly. If not then Calcite will
have to translate/delegate into a MetaModel query. Over time I don't think
there's any reason except for backwards compatibility that we wouldn't want to
fully adopt Calcite into all the MetaModel adaptors. But till then we could
instead wrap calcite around MetaModel and thereby providing us with API
unification that way.
> Add wrapper for Apache Metamodel adapters
> -----------------------------------------
>
> Key: CALCITE-1304
> URL: https://issues.apache.org/jira/browse/CALCITE-1304
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: Julian Hyde
>
> Apache Metamodel has adapters for a lot of data sources. It would be great if
> those adapters could be re-used as Calcite adapters (and potentially Drill
> adapters also). I was speaking to [~kaspersor] (Metamodel PMC member) today
> and he likes the idea.
> I don't know whether there would be any loss of efficiency going through a
> wrapper, but I suspect not.
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