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https://issues.apache.org/jira/browse/CASSANDRA-6151?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15427547#comment-15427547
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nicerobot edited comment on CASSANDRA-6151 at 8/24/16 2:42 AM:
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Hypothetically, i can create lots of single-node results, join them, and
hopefully the partitioning is retained for processing the data further.
Also, what if my partition key clusters millions of rows? I want to iterate
those millions of rows on each node.
was (Author: nicerobot):
Hypothetically, i can create lots of single-node results, join them, and
hopefully the partitioning is retained for processing the data further.
> CqlPagingRecorderReader Used when Partition Key Is Explicitly Stated
> --------------------------------------------------------------------
>
> Key: CASSANDRA-6151
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6151
> Project: Cassandra
> Issue Type: Bug
> Reporter: Russell Spitzer
> Assignee: Alex Liu
> Priority: Minor
> Attachments: 6151-1.2-branch.txt, 6151-v2-1.2-branch.txt,
> 6151-v3-1.2-branch.txt, 6151-v4-1.2.10-branch.txt
>
>
> From
> http://stackoverflow.com/questions/19189649/composite-key-in-cassandra-with-pig/19211546#19211546
> The user was attempting to load a single partition using a where clause in a
> pig load statement.
> CQL Table
> {code}
> CREATE table data (
> occurday text,
> seqnumber int,
> occurtimems bigint,
> unique bigint,
> fields map<text, text>,
> primary key ((occurday, seqnumber), occurtimems, unique)
> )
> {code}
> Pig Load statement Query
> {code}
> data = LOAD
> 'cql://ks/data?where_clause=seqnumber%3D10%20AND%20occurday%3D%272013-10-01%27'
> USING CqlStorage();
> {code}
> This results in an exception when processed by the the CqlPagingRecordReader
> which attempts to page this query even though it contains at most one
> partition key. This leads to an invalid CQL statement.
> CqlPagingRecordReader Query
> {code}
> SELECT * FROM "data" WHERE token("occurday","seqnumber") > ? AND
> token("occurday","seqnumber") <= ? AND occurday='A Great Day'
> AND seqnumber=1 LIMIT 1000 ALLOW FILTERING
> {code}
> Exception
> {code}
> InvalidRequestException(why:occurday cannot be restricted by more than one
> relation if it includes an Equal)
> {code}
> I'm not sure it is worth the special case but, a modification to not use the
> paging record reader when the entire partition key is specified would solve
> this issue.
> h3. Solution
> If it have EQUAL clauses for all the partitioning keys, we use Query
> {code}
> SELECT * FROM "data"
> WHERE occurday='A Great Day'
> AND seqnumber=1 LIMIT 1000 ALLOW FILTERING
> {code}
> instead of
> {code}
> SELECT * FROM "data"
> WHERE token("occurday","seqnumber") > ?
> AND token("occurday","seqnumber") <= ?
> AND occurday='A Great Day'
> AND seqnumber=1 LIMIT 1000 ALLOW FILTERING
> {code}
> The base line implementation is to retrieve all data of all rows around the
> ring. This new feature is to retrieve all data of a wide row. It's a one
> level lower than the base line. It helps for the use case where user is only
> interested in a specific wide row, so the user doesn't spend whole job to
> retrieve all the rows around the ring.
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