[ 
https://issues.apache.org/jira/browse/CASSANDRA-16217?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17236366#comment-17236366
 ] 

David Capwell commented on CASSANDRA-16217:
-------------------------------------------

There have been conversations about migrating from python to jvm dtest and the 
main point is we shouldn't delete python dtests.  python dtests cover vnode 
case as well but jvm does not, so if we delete python dtests in favor of jvm 
dtest we actually loose coverage.  I added a marker saying a test was ported to 
jvm-dtest, this will skip novnode case but still run in vnode case.

> Minimal 4.0 COMPACT STORAGE backport
> ------------------------------------
>
>                 Key: CASSANDRA-16217
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-16217
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Legacy/CQL
>            Reporter: Alex Petrov
>            Assignee: Alex Petrov
>            Priority: Normal
>             Fix For: 4.0-beta4
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> There are several behavioural changes related to compact storage, and these 
> differences are larger than most of us have anticipated: we first thought 
> there’ll be that “appearing column”, but there’s implicit nulls in 
> clusterings thing, and row vs column deletion.
> Some of the recent issues on the subject are: CASSANDRA-16048, which allows 
> to ignore these differences. The other one was trying to improve user 
> experience of anyone still using compact storage: CASSANDRA-15811.
> Easily reproducible differernces are:
> (1) hidden columns show up, which breaks SELECT * queries
>  (2) DELETE v and UPDATE v WITH TTL would result into row removals in 
> non-dense compact tables (CASSANDRA-16069)
>  (3) INSERT allows skipping clusterings, which are filled with nulls by 
> default.
> Some of these are tricky to support, as 15811 has shown. Anyone on OSS side 
> who might want to upgrade to 4.0 while still using compact storage might be 
> affected by being forced into one of these behaviours.
> Possible solutions are to document these behaviours, or to bring back a 
> minimal set of COMPACT STORAGE to keep supporting these.
> It looks like it is possible to leave some of the functionality related to 
> DENSE flag and allow it to be present in 4.0, but only for these three (and 
> potential related, however not direrclty visible) cases.
> [~e.dimitrova] since you were working on removal on compact storage, wanted 
> to reassure that this is not a revert of your patch. On contrary: your patch 
> was instrumental in identifying the right places.
> cc [~slebresne] [~aleksey] [~benedict] [~marcuse]
> |[patch|https://github.com/apache/cassandra/pull/785]|[ci|https://app.circleci.com/pipelines/github/ifesdjeen/cassandra?branch=13994-followup]|



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org
For additional commands, e-mail: commits-h...@cassandra.apache.org

Reply via email to