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https://issues.apache.org/jira/browse/CASSANDRA-12127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15360295#comment-15360295
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Benjamin Lerer commented on CASSANDRA-12127:
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bq. As this behavior (passing an empty buffer to textAsBlob()) is allowable and
correct as of 3.0 and trunk, I propose we fix this for 2.1 and 2.2
I agree with your suggestion. It makes more sense if 3.0 allows those queries.
bq. I suspect it's the same fix, though I'm not very familiar with this part of
the code base
This problem was solved with the Storage engine refactoring (CASSANDRA-8099).
By consequence, it will not be possible to do the same in 2.1 and 2.2.
As the behavior of those queries is pretty simple, I believe that we can fix
the problem at the {{SelectStatement}} level by doing some special handling for
those queries. It will not be the nicest solution but, as the problem has been
properly solved in 3.0, I think it is acceptable.
> 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
> Reporter: Benjamin Lerer
> Assignee: Benjamin Lerer
>
> 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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