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From Henning Kropp <Kr...@nurago.com>
Subject AW: Request Timeout with Composite Columns and CQL3
Date Tue, 26 Jun 2012 14:00:48 GMT
Thanks for the reply. Should have thought about looking into the log files sooner. An AssertionError
happens at execution. I haven't figured out yet why. Any input is very much appreciated:

ERROR [ReadStage:1] 2012-06-26 15:49:54,481 AbstractCassandraDaemon.java (line 134) Exception
in thread Thread[ReadStage:1,5,main]
java.lang.AssertionError: Added column does not sort as the last column
	at org.apache.cassandra.db.ArrayBackedSortedColumns.addColumn(ArrayBackedSortedColumns.java:130)
	at org.apache.cassandra.db.AbstractColumnContainer.addColumn(AbstractColumnContainer.java:107)
	at org.apache.cassandra.db.AbstractColumnContainer.addColumn(AbstractColumnContainer.java:102)
	at org.apache.cassandra.db.filter.SliceQueryFilter.collectReducedColumns(SliceQueryFilter.java:141)
	at org.apache.cassandra.db.filter.QueryFilter.collateColumns(QueryFilter.java:139)
	at org.apache.cassandra.db.CollationController.collectAllData(CollationController.java:283)
	at org.apache.cassandra.db.CollationController.getTopLevelColumns(CollationController.java:63)
	at org.apache.cassandra.db.ColumnFamilyStore.getTopLevelColumns(ColumnFamilyStore.java:1321)
	at org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1183)
	at org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1118)
	at org.apache.cassandra.db.Table.getRow(Table.java:374)
	at org.apache.cassandra.db.SliceFromReadCommand.getRow(SliceFromReadCommand.java:69)
	at org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:816)
	at org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:1250)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)


BTW: I really would love to understand as of why the combined comparator will not allow two
ranges be specified for two key parts. Obviously I still lack a profound understanding of
cassandras architecture to have a clue.
And while client side filtering might seem like a valid option I am still trying to get might
head around a cassandra data model that would allow this.

best regards
 
________________________________________
Von: Sylvain Lebresne [sylvain@datastax.com]
Gesendet: Dienstag, 26. Juni 2012 10:21
Bis: user@cassandra.apache.org
Betreff: Re: Request Timeout with Composite Columns and CQL3

On Mon, Jun 25, 2012 at 11:10 PM, Henning Kropp <Kropp@nurago.com> wrote:
> Hi,
>
> I am running into timeout issues using composite columns in cassandra 1.1.1
> and cql 3.
>
> My keyspace and table is defined as the following:
>
> create keyspace bn_logs
>     with strategy_options = [{replication_factor:1}]
>     and placement_strategy = 'org.apache.cassandra.locator.SimpleStrategy';
>
> CREATE TABLE logs (
>   id text,
>   ref text,
>   time bigint,
>   datum text,
>   PRIMARY KEY(id, ref, time)
> );
>
> I import some data to the table by using a combination of the thrift
> interface and the hector Composite.class by using its serialization as the
> column name:
>
> Column col = new Column(composite.serialize());
>
> This all seems to work fine until I try to execute the following query which
> leads to a request timeout:
>
> SELECT datum FROM logs WHERE id='861' and ref = 'raaf' and time > '3000';

If it timeouts the likely reason is that this query selects more data
than the machine is able to fetch before the timeout. You can either
add a limit to the query, or increase the timeout.
If that doesn't seem to fix it, it might be worth checking the server
log to see if there isn't an error.

> I really would like to figure out, why running this query on my laptop
> (single node, for development) will not finish. I also would like to know if
> the following query would actually work
>
> SELECT datum FROM logs WHERE id='861' and ref = 'raaf*' and time > '3000';

It won't. You can perform the following query:

SELECT datum FROM logs WHERE id='861' and ref = 'raaf';

which will select every datum whose ref starts with 'raaf', but then
you cannot restrict
the time parameter, so you will get ref where the time is <= 3000. Of
course you can
always filter client side if that is an option.

> or how else there is a way to define a range for the second component of the
> column key?

As described above, you can define a range on the second component, but then you
won't be able to restrict on the 3rd component.

>
> Any thoughts?
>
> Thanks in advance and kind regards
> Henning
>

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