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https://issues.apache.org/jira/browse/CASSANDRA-12127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15365999#comment-15365999
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Benjamin Lerer commented on CASSANDRA-12127:
--------------------------------------------
Thanks for the patch. Unfortunatly, is only covers the problem of single slice
restrictions with an empty start bound and the solution will not work if the
table is sorted in descending order.
I should have a patch ready today. Writing the tests to cover (hopefully) all
of the possible queries took much more time than I expected.
> Queries with empty ByteBuffer values in clustering column restrictions fail
> for non-composite compact tables
> ------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-12127
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12127
> Project: Cassandra
> Issue Type: Bug
> Components: CQL
> Reporter: Benjamin Lerer
> Assignee: Benjamin Lerer
> Fix For: 2.1.x, 2.2.x
>
> Attachments: 12127.txt
>
>
> For the following table:
> {code}
> CREATE TABLE myTable (pk int,
> c blob,
> value int,
> PRIMARY KEY (pk, c)) WITH COMPACT STORAGE;
> INSERT INTO myTable (pk, c, value) VALUES (1, textAsBlob('1'), 1);
> INSERT INTO myTable (pk, c, value) VALUES (1, textAsBlob('2'), 2);
> {code}
> The query: {{SELECT * FROM myTable WHERE pk = 1 AND c > textAsBlob('');}}
> Will result in the following Exception:
> {code}
> java.lang.ClassCastException:
> org.apache.cassandra.db.composites.Composites$EmptyComposite cannot be cast
> to org.apache.cassandra.db.composites.CellName
> at
> org.apache.cassandra.db.composites.AbstractCellNameType.cellFromByteBuffer(AbstractCellNameType.java:188)
> at
> org.apache.cassandra.db.composites.AbstractSimpleCellNameType.makeCellName(AbstractSimpleCellNameType.java:125)
> at
> org.apache.cassandra.db.composites.AbstractCellNameType.makeCellName(AbstractCellNameType.java:254)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.makeExclusiveSliceBound(SelectStatement.java:1206)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.applySliceRestriction(SelectStatement.java:1214)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.processColumnFamily(SelectStatement.java:1292)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.process(SelectStatement.java:1259)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.processResults(SelectStatement.java:299)
> [...]
> {code}
> The query: {{SELECT * FROM myTable WHERE pk = 1 AND c < textAsBlob('');}}
> Will return 2 rows instead of 0.
> The query: {{SELECT * FROM myTable WHERE pk = 1 AND c = textAsBlob('');}}
> {code}
> java.lang.AssertionError
> at
> org.apache.cassandra.db.composites.SimpleDenseCellNameType.create(SimpleDenseCellNameType.java:60)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.addSelectedColumns(SelectStatement.java:853)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.getRequestedColumns(SelectStatement.java:846)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.makeFilter(SelectStatement.java:583)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.getSliceCommands(SelectStatement.java:383)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.getPageableCommand(SelectStatement.java:253)
> [...]
> {code}
> I checked 2.0 and {{SELECT * FROM myTable WHERE pk = 1 AND c >
> textAsBlob('');}} works properly but {{SELECT * FROM myTable WHERE pk = 1 AND
> c < textAsBlob('');}} return the same wrong results than in 2.1.
> The {{SELECT * FROM myTable WHERE pk = 1 AND c = textAsBlob('');}} is
> rejected if a clear error message: {{Invalid empty value for clustering
> column of COMPACT TABLE}}.
> As it is not possible to insert an empty ByteBuffer value within the
> clustering column of a non-composite compact tables those queries do not
> have a lot of meaning. {{SELECT * FROM myTable WHERE pk = 1 AND c <
> textAsBlob('');}} and {{SELECT * FROM myTable WHERE pk = 1 AND c =
> textAsBlob('');}} will return nothing
> and {{SELECT * FROM myTable WHERE pk = 1 AND c > textAsBlob('');}} will
> return the entire partition (pk = 1).
> In my opinion those queries should probably all be rejected as it seems that
> the fact that {{SELECT * FROM myTable WHERE pk = 1 AND c > textAsBlob('');}}
> was accepted in {{2.0}} was due to a bug.
> I am of course open to discussion.
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