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https://issues.apache.org/jira/browse/CASSANDRA-952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12867174#action_12867174
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Jeremy Hanna edited comment on CASSANDRA-952 at 5/13/10 12:50 PM:
------------------------------------------------------------------
Reviewing part of it and I know this wasn't part of the change - but in
RackAwareStrategy couldn't we save some instruction execution by moving the
check for whether we already have found another datacenter/rack outside of the
checks? Like so:
{code}
Token t = iter.next();
// First try to find one in a different data center
// If we have already found something in a diff datacenter no need to find
another
if (!bDataCenter)
{
if
(!snitch.getDatacenter(metadata.getEndpoint(primaryToken)).equals(snitch.getDatacenter(metadata.getEndpoint(t))))
{
endpoints.add(metadata.getEndpoint(t));
bDataCenter = true;
continue;
}
}
// Now try to find one on a different rack
// If we have already found something in a diff rack no need to find another
if (!bOtherRack)
{
if
(!snitch.getRack(metadata.getEndpoint(primaryToken)).equals(snitch.getRack(metadata.getEndpoint(t)))
&&
snitch.getDatacenter(metadata.getEndpoint(primaryToken)).equals(snitch.getDatacenter(metadata.getEndpoint(t))))
{
endpoints.add(metadata.getEndpoint(t));
bOtherRack = true;
continue;
}
}
{code}
not that big of a deal, but since it's done on every write, might be helpful.
Maybe I'm missing something there though...
was (Author: jeromatron):
Reviewing part of it and I know this wasn't part of the change - but in
RackAwareStrategy couldn't we save some instruction execution by moving the
check for whether we already have found another datacenter/rack outside of the
checks? Like so:
<code>
Token t = iter.next();
// First try to find one in a different data center
// If we have already found something in a diff datacenter no need to find
another
if (!bDataCenter)
{
if
(!snitch.getDatacenter(metadata.getEndpoint(primaryToken)).equals(snitch.getDatacenter(metadata.getEndpoint(t))))
{
endpoints.add(metadata.getEndpoint(t));
bDataCenter = true;
continue;
}
}
// Now try to find one on a different rack
// If we have already found something in a diff rack no need to find another
if (!bOtherRack)
{
if
(!snitch.getRack(metadata.getEndpoint(primaryToken)).equals(snitch.getRack(metadata.getEndpoint(t)))
&&
snitch.getDatacenter(metadata.getEndpoint(primaryToken)).equals(snitch.getDatacenter(metadata.getEndpoint(t))))
{
endpoints.add(metadata.getEndpoint(t));
bOtherRack = true;
continue;
}
}
</code>
not that big of a deal, but since it's done on every write, might be helpful.
Maybe I'm missing something there though...
> DC Quorum broken @ trunk
> ------------------------
>
> Key: CASSANDRA-952
> URL: https://issues.apache.org/jira/browse/CASSANDRA-952
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.6
> Environment: Linux, Cassandra
> Reporter: Vijay
> Assignee: Vijay
> Priority: Minor
> Fix For: 0.7, 0.8
>
> Attachments:
> 0001-clean-out-callback-purging-from-truncate-writerh.txt,
> 0002-dcquorum-fixes.txt, 952-Canges_To_Stategy_V002.txt,
> 952-Change_BlockFor.txt, 952-Changes_To_ResponseHandler_v002.txt,
> 952-Fix_Refactor_DCStatergy.txt, 952-v3.txt, 952-v4.txt, 952-v5.txt,
> DC-Config.xml
>
>
> Currently DCQuorum is broken in trunk, Suggesting the following fix...
> Write to DC's
> 1) Move determineBlockFor(int expandedTargets, ConsistencyLevel
> consistency_level) to AbstractEndpointSnitch
> 2) Add the same to support DC Quorum in DatacenterShardStategy
> Read to DC's
> 1) find suitable nodes was a list which was returning a list of local DC's
> earlier but now it is just one node and MD is been sent by other nodes. Need
> to have an option to even avoid MD from other DC's?
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