Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@cassandra.apache.org
Received-SPF: pass (nike.apache.org: domain of jbellis@gmail.com designates
 74.125.82.44 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:from:date:message-id:subject:to
         :content-type:content-transfer-encoding;
        b=hYYaKmbpBvuiRkfuIlI32DcepaNIShBR/92eFazn3wa5+jxliDt/vyJLRZt9AM7g7I
         x9+MH1+bhIuB8mIfZogkv3bFtic+TcZbCxwrcSVofO9/UkDnJ9ADqx6Se9e6WKfB5+o4
         BkePxZP6nNJNNZgooh/pAl+xHg4+1E0EtJ+Dk=
MIME-Version: 1.0
In-Reply-To: <BANLkTi=anHFjcGYq-PMiwPQuJMN5=M-4vQ@mail.gmail.com>
References: <BANLkTi=anHFjcGYq-PMiwPQuJMN5=M-4vQ@mail.gmail.com>
From: Jonathan Ellis <jbellis@gmail.com>
Date: Fri, 10 Jun 2011 21:09:09 -0500
Message-ID: <BANLkTimsNzDM9sza2WwZY00-mJ0DVw7sPA@mail.gmail.com>
Subject: Re: simple get_slice() gives error?
To: user@cassandra.apache.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

Don't use destructive operations on the bytebuffer, always use e.g.
getLong(buffer.position)

On Fri, Jun 10, 2011 at 8:47 PM, Yang <teddyyyy123@gmail.com> wrote:
> I'm using thrift.CassandraServer directly within the same cassandra JVM t=
o
> accomplish my application tasks.
> (I understand that this is not the normal usage mode...., but the error h=
ere
> may also be appearing in Cassandra server code
> development, so I thought it could be of some value to look at )
> I ran into some issues when I try to parse out values from column name
> ByteBuffer:
>
> something like the following
> List<ColumnOrSuperColumn> cols =3D cassandra_svr.get_slice(key, path,
> predicate, ConsistencyLevel.ONE);
> for(ColumnOrSuperColumn colOrSup: cols) {
> Column col =3D colOrSup.column;
> long ts =3D col.name.getLong(); =A0<=3D=3D=3D=3D=3D=3D
>
> sometimes the last sentence gives error "ByteBuffer underflow", I checked
> that the buffer size is 8 bytes, and the "pos" points to 8 already. =A0it
> seems that somewhere in
> thrift.CassandraServer line 179---195
> =A0 =A0 public List<ColumnOrSuperColumn> thriftifyColumns(Collection<ICol=
umn>
> columns, boolean reverseOrder)
> =A0 =A0 {
> ...........................................................
> =A0 =A0 =A0 =A0 =A0 =A0 {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Column thrift_column =3D new
> Column(column.name()).setValue(column.value()).setTimestamp(column.timest=
amp());
> the ctor of Column(Column ) is used, which just uses the old column.name
> buffer, which also preserves the pos.
>
> is this some error on server code? (looks a flip() is needed somewhere)
>
> Thanks
> Yang


--=20
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com