cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6783) Collections should have a proper compare() method for UDT
Date Tue, 11 Mar 2014 20:32:55 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6783?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13930905#comment-13930905
] 

Jonathan Ellis commented on CASSANDRA-6783:
-------------------------------------------

([~thobbs] to review)

> Collections should have a proper compare() method for UDT
> ---------------------------------------------------------
>
>                 Key: CASSANDRA-6783
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6783
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Sylvain Lebresne
>            Assignee: Sylvain Lebresne
>             Fix For: 2.1 beta2
>
>         Attachments: 6783.txt
>
>
> So far, ListType, SetType and MapType don't have a proper implementation of compare()
(they throw UnsupportedOperationException) because we haven't need one since as far as the
cell comparator is concenred, only parts of a collection ends up in the comparator and need
to be compared, but the full collection itself does not.
> But with UDT can nest a collection and that sometimes require to be able to compare them.
Typically, I pushed a dtest [here|https://github.com/riptano/cassandra-dtest/commit/290e9496d1b2c45158c7d7f5487d09ba48897a7f]
that ends up throwing:
> {noformat}
> java.lang.UnsupportedOperationException: CollectionType should not be use directly as
a comparator
>         at org.apache.cassandra.db.marshal.CollectionType.compare(CollectionType.java:72)
~[main/:na]
>         at org.apache.cassandra.db.marshal.CollectionType.compare(CollectionType.java:37)
~[main/:na]
>         at org.apache.cassandra.db.marshal.AbstractType.compareCollectionMembers(AbstractType.java:174)
~[main/:na]
>         at org.apache.cassandra.db.marshal.AbstractCompositeType.compare(AbstractCompositeType.java:101)
~[main/:na]
>         at org.apache.cassandra.db.marshal.AbstractCompositeType.compare(AbstractCompositeType.java:35)
~[main/:na]
>         at java.util.TreeMap.compare(TreeMap.java:1188) ~[na:1.7.0_45]
>         at java.util.TreeMap.put(TreeMap.java:531) ~[na:1.7.0_45]
>         at java.util.TreeSet.add(TreeSet.java:255) ~[na:1.7.0_45]
>         at org.apache.cassandra.cql3.Sets$DelayedValue.bind(Sets.java:205) ~[main/:na]
>         at org.apache.cassandra.cql3.Sets$Literal.prepare(Sets.java:91) ~[main/:na]
>         at org.apache.cassandra.cql3.UserTypes$Literal.prepare(UserTypes.java:60) ~[main/:na]
>         at org.apache.cassandra.cql3.Operation$SetElement.prepare(Operation.java:221)
~[main/:na]
>         at org.apache.cassandra.cql3.statements.UpdateStatement$ParsedUpdate.prepareInternal(UpdateStatement.java:201)
~[main/:na]
> ...
> {noformat}
> Note that this stack doesn't involve cell name comparison at all, it's just that CQL3
sometimes uses a SortedSet underneath to deal with set literals (since internal sets are sorted
by their value), and so when a set contains UDT that has set themselves, we need the collection
comparison. That being said, for some cases like having a UDT as a map key, we do would need
collections to be comparable for the purpose of cell name comparison.
> Attaching relatively simple patch. The patch is a bit bigger than it should be because
while adding the 3 simple compare() method, I realized that we had methods to read a short
length (2 unsigned short) from a ByteBuffer duplicated all over the place and that it was
time to consolidate that in ByteBufferUtil where it should have been from day one (thus removing
the duplication). I can separate that trivial refactor in a separate patch if we really need
to, but really, the new stuff is the compare() method implementation in ListType, SetType
and MapType and the rest is a bit of trivial cleanup. 



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message