[
https://issues.apache.org/jira/browse/PHOENIX-294?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14177873#comment-14177873
]
Lars Hofhansl commented on PHOENIX-294:
---------------------------------------
Brainstormed with James a bit today. Other options include:
* mark column deleted and disallow re-creating the same column again
* mark column deleted and clean up lazily during compactions (don't even have
to wait for a major compaction). Would need to keep track of major compaction
that followed a drop of a column to know when it is safe to reuse that column
name again
> Avoid adding delete markers for rows when dropping a column
> -----------------------------------------------------------
>
> Key: PHOENIX-294
> URL: https://issues.apache.org/jira/browse/PHOENIX-294
> Project: Phoenix
> Issue Type: Task
> Reporter: larsh
>
> Talked to James a bit. Currently when a column is dropped we place delete
> markers for this column on each row. This is very inefficient when there are
> many row.
> Another option is to drop the column from just the metadata.
> Since the schema is versioned the only problematic queries would be a
> wildcard (select * from...) queries.
> For those wildcard queries we can examine the current schema (at the
> appropriate timestamp) and expand the * to the actual set of columns.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
