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https://issues.apache.org/jira/browse/CASSANDRA-4175?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13678198#comment-13678198
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Edward Capriolo commented on CASSANDRA-4175:
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{quote} Schema has never really been eventually consistent since you can't do
anything useful until the schema has propagated. Fortunately, since schema
changes are rare, this isn't a problem in practice.
{quote}
I do not see how it will not be a problem in practice. In a single datacenter
deployment it means you will not be able to add schema is zookeeper is not up.
In a multi-data center deployment I do not know what it means. Based on how you
want to interpret multi-datacenter zookeeper. Do all datacenters need to be
reachable for schema changes? Then it is not AP.
http://zookeeper-user.578899.n2.nabble.com/Managing-multi-site-clusters-with-Zookeeper-td4685686.html
{quote}
Nope, since it's 2 bytes for name length, then 2 for the name. To win vs 32bit
int you'd have to have a single-letter name. (And of course any use of
CompositeType blows this right out.
{quote}
Seriously. Why aren't people using 1 or 2 character column names? That would
give you something like 676 and then in the schema we could just store a
comment like 'pw means password'. Problem solved.
> Reduce memory (and disk) space requirements with a column name/id map
> ---------------------------------------------------------------------
>
> Key: CASSANDRA-4175
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4175
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Jonathan Ellis
> Fix For: 2.1
>
>
> We spend a lot of memory on column names, both transiently (during reads) and
> more permanently (in the row cache). Compression mitigates this on disk but
> not on the heap.
> The overhead is significant for typical small column values, e.g., ints.
> Even though we intern once we get to the memtable, this affects writes too
> via very high allocation rates in the young generation, hence more GC
> activity.
> Now that CQL3 provides us some guarantees that column names must be defined
> before they are inserted, we could create a map of (say) 32-bit int column
> id, to names, and use that internally right up until we return a resultset to
> the client.
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