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https://issues.apache.org/jira/browse/CASSANDRA-8576?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14536341#comment-14536341
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Piotr Kołaczkowski commented on CASSANDRA-8576:
-----------------------------------------------
Some comments were not addressed.
{noformat}
boolean containToken;
for (Range<Token> subrange : ranges)
{
//make sure subrange contains the token
containToken = false;
if (token != null)
{
if (subrange.contains(token))
containToken = true;
else
continue;
}
ColumnFamilySplit split =
new ColumnFamilySplit(
factory.toString(subrange.left),
factory.toString(subrange.right),
subSplit.getRow_count(),
endpoints);
if (containToken)
split.setPartitionKeyEqQuery(containToken);
logger.debug("adding {}", split);
{noformat}
Multiple code smells in this fragment:
* boolean flag declared in a needlessly broad scope. If something is used only
inside a loop, it should be declared only inside the loop.
* continue controlled by a boolean flag
* redundant if (the code is equivalent without if (containToken)
I simplified it for you:
{noformat}
for (Range<Token> subrange : ranges)
{
boolean containsToken = token != null &&
subrange.contains(token);
if (token == null || containsToken) {
ColumnFamilySplit split =
new ColumnFamilySplit(
factory.toString(subrange.left),
factory.toString(subrange.right),
subSplit.getRow_count(),
endpoints);
split.setPartitionKeyEqQuery(containsToken);
logger.debug("adding {}", split);
splits.add(split);
}
}
{noformat}
> Primary Key Pushdown For Hadoop
> -------------------------------
>
> Key: CASSANDRA-8576
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8576
> Project: Cassandra
> Issue Type: Improvement
> Components: Hadoop
> Reporter: Russell Alexander Spitzer
> Assignee: Alex Liu
> Fix For: 2.1.x
>
> Attachments: 8576-2.1-branch.txt, 8576-trunk.txt,
> CASSANDRA-8576-v2-2.1-branch.txt
>
>
> I've heard reports from several users that they would like to have predicate
> pushdown functionality for hadoop (Hive in particular) based services.
> Example usecase
> Table with wide partitions, one per customer
> Application team has HQL they would like to run on a single customer
> Currently time to complete scales with number of customers since Input Format
> can't pushdown primary key predicate
> Current implementation requires a full table scan (since it can't recognize
> that a single partition was specified)
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