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Posted to commits@cassandra.apache.org by "Donald Smith (JIRA)" <ji...@apache.org> on 2015/03/18 21:50:40 UTC
[jira] [Updated] (CASSANDRA-8990) Allow clients to override the DCs
the data gets sent to, per write request, overriding keyspace settings
[ https://issues.apache.org/jira/browse/CASSANDRA-8990?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Donald Smith updated CASSANDRA-8990:
------------------------------------
Description:
Currently each keyspace specifies how many replicas to write to each data center. In CQL one specifies:
{noformat}
WITH replication = {
'class': 'NetworkTopologyStrategy',
'DC1: '3',
'DC2': '3'
}
{noformat}
But in some use cases there's no need to write certain rows to a certain datacenter. Requiring the user to create two keyspaces is burdensome and complicates code and queries.
For example, we have global replication of our data to multiple continents. But we want the option to send only certain rows globally with certain values for certain columns -- e.g., only for users that visited that country.
Cassandra and CQL should support the ability of client code to specify, on a per request basis, that a write should go only to specified data centers (probably restricted to being a subset of the DCs specified in the keyspace).
was:
Currently each keyspace specifies how many replicas to write to each data center. In CQL one specifies:
{noformat}
WITH replication = {
'class': 'NetworkTopologyStrategy',
'DC1: '3',
'DC2': '3'
}
{noformat}
But in some use cases there's no need to write certain rows to a certain datacenter. Requiring the user to create two keyspaces is burdensome and complicates code and queries.
For example, we have global replication of our data to multiple continents. But we want the option to send only certain rows globally with certain values for certain columns -- e.g., only for users that visited that country).
Cassandra and CQL should support the ability of client code to specify, on a per request basis, that a write should go only to specified data centers.
> Allow clients to override the DCs the data gets sent to, per write request, overriding keyspace settings
> --------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-8990
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8990
> Project: Cassandra
> Issue Type: New Feature
> Reporter: Donald Smith
>
> Currently each keyspace specifies how many replicas to write to each data center. In CQL one specifies:
> {noformat}
> WITH replication = {
> 'class': 'NetworkTopologyStrategy',
> 'DC1: '3',
> 'DC2': '3'
> }
> {noformat}
> But in some use cases there's no need to write certain rows to a certain datacenter. Requiring the user to create two keyspaces is burdensome and complicates code and queries.
> For example, we have global replication of our data to multiple continents. But we want the option to send only certain rows globally with certain values for certain columns -- e.g., only for users that visited that country.
> Cassandra and CQL should support the ability of client code to specify, on a per request basis, that a write should go only to specified data centers (probably restricted to being a subset of the DCs specified in the keyspace).
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