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From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-4415) Add cursor API/auto paging to the native CQL protocol
Date Thu, 05 Jul 2012 16:53:34 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-4415?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13407268#comment-13407268
] 

Sylvain Lebresne commented on CASSANDRA-4415:
---------------------------------------------

I've written a good chunk of code for this but there is one big issue with this I'm not sure
how to solve best: this will "break" isolation from a user perspective.

More precisely, the goal is that from the user point of view all of this is transparent: it
does a query and will then fetch query one by one and the driver will use that feature underneath
to having getting into OOM situation and to avoid timeout for query yielding lots of result.
However, since underneath we'll do multiple query, it might look as if there was not isolation
if your unlucky with the timing of the requests.

So I don't know what to do about that. I unfortunately don't see a solution to fix it per-se,
so the question is how to make that acceptable. 
                
> Add cursor API/auto paging to the native CQL protocol
> -----------------------------------------------------
>
>                 Key: CASSANDRA-4415
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4415
>             Project: Cassandra
>          Issue Type: New Feature
>    Affects Versions: 1.2
>            Reporter: Sylvain Lebresne
>
> The goal here would be to use a query paging mechanism to the CQL native protocol. Typically
the client/server with that would look something like this:
> {noformat}
> C sends query to S.
> S sends N first rows matching the query + flag saying the response is not complete
> C requests the next N rows
> S sends N next rows + flag saying whether there is more
> C requests the next N rows
> ...
> S sends last rows + flag saying there is no more result
> {noformat}
> The clear goal is for user to not have to worry about limiting queries and doing manual
paging.

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