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Posted to issues@calcite.apache.org by "Platon Bibik (Jira)" <ji...@apache.org> on 2020/01/23 16:16:00 UTC
[jira] [Commented] (CALCITE-2426) Calcite - mongodb - Returns row
but no data displayed.
[ https://issues.apache.org/jira/browse/CALCITE-2426?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17022235#comment-17022235 ]
Platon Bibik commented on CALCITE-2426:
---------------------------------------
Hi [~citsathishcs@gmail.com], [~sereda] and all,
Was testing out Calcite recently for my project (particularly – the MongoDB adapter), as I was really impressed by the idea behind the tool and capabilities it provides. I have found this ticket while trying to use * projection in mongo requests. Unfortunately, as [~citsathishcs@gmail.com] already pointed out, there are't any comprehensive docs on MongoDB adapter, and I had to figure out things myself by reading the source code.
The problem I am having is that when a "star" projection is used in mongo queries, result set's rows contain one column {{_MAP}} with value {{null}}. After some debugging, I figured out that the {{MongoEnumerator}} is using a wrong getter in the calls to the {{MongoTable's}} methods (in my case it was aggregate). While it seems like it should choose {{mapGetter}}, it chooses {{singletonGetter}}, because the {{fields}} parameter passed to the +{{Function1<Document, Object> getter(List<Entry<String, Class>> fields)}}+ method is non-null (contains one {{_MAP}} element).
Is this behaviour intended? Or are there any plans/ideas on how to fix it?
Any comment/suggestion would be highly appreciated. I really hope that in the end this won't stop me from using the lib =)
> Calcite - mongodb - Returns row but no data displayed.
> ------------------------------------------------------
>
> Key: CALCITE-2426
> URL: https://issues.apache.org/jira/browse/CALCITE-2426
> Project: Calcite
> Issue Type: Bug
> Reporter: sathishkumar
> Priority: Critical
>
> sqlline version 1.3.0
> sqlline> !connect jdbc:calcite:schemaFactory=org.apache.calcite.adapter.mongodb.MongoSchemaFactory;schema.host=localhost;schema.database=*****; admin admin
> 0: jdbc:calcite:schemaFactory=org.apache.calc> !tables
>
> +------------+------------++------------------------++-------------------++-----------------------++--------------------
> |TABLE_CAT|TABLE_SCHEM|TABLE_NAME|TABLE_TYPE|REMARKS|TYPE_CAT|TYPE_SCHEM|TYPE_NAME|SELF_REFERENCING_C|
> +------------+------------++------------------------++-------------------++-----------------------++--------------------
> | |adhoc|company_preferences|TABLE| | | | | |
> | |adhoc|property|TABLE| | | | | |
> | |adhoc|templates|TABLE| | | | | |
> | |adhoc|user_preferences|TABLE| | | | | |
> *| | adhoc | users | TABLE | | | | | |*
> | |metadata|COLUMNS|SYSTEM TABLE| | | | | |
> | |metadata|TABLES|SYSTEM TABLE| | | | | |
> +------------+------------++------------------------++-------------------++-----------------------++--------------------
> 0: jdbc:calcite:schemaFactory=org.apache.calc> *select * from "users";*
> +------+
> |_MAP|
> +------+
> | |
> +------+
> *1 row selected (0.584 seconds)*
> 0: jdbc:calcite:schemaFactory=org.apache.calc>
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