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From Leonid Ilyevsky <lilyev...@mooncapital.com>
Subject RE: help using org.apache.cassandra.cql3
Date Wed, 11 Jul 2012 13:42:30 GMT
Thanks Sylvain, I actually tried the prepared batch, works fine. I did the 1000 rows in one
batch, 20 columns each, and it was good. Then I tried 10000, and it still works, I am going
to measure which way it is faster overall.

-----Original Message-----
From: Sylvain Lebresne [mailto:sylvain@datastax.com]
Sent: Wednesday, July 11, 2012 9:32 AM
To: user@cassandra.apache.org
Subject: Re: help using org.apache.cassandra.cql3

When I said to use the BATCH statement I mean't using a query that is
a BATCH statement, so something like:
  BEGIN BATCH
    INSERT ...;
    INSERT ...;
    ...
  APPLY BATCH;

If you want to that from java, you will want to look at the jdbc
driver (http://code.google.com/a/apache-extras.org/p/cassandra-jdbc/),
though I don't know what is the status of the support for CQL3.

On Wed, Jul 11, 2012 at 2:18 PM, Leonid Ilyevsky
<lilyevsky@mooncapital.com> wrote:
> Is it OK to put 10000 of update statements in one
> batch, with 50000 question marks in it? The set that many variables?

Yes batch statement can be prepared and in theory there isn't much
limit on the number of update statement (nor question marks) you can
put in one batch. However, the way C* work best is if you do
reasonably sized batches. It's even more true for CQL in the sense
that by using a huge batch statement you'll pay the parsing. So you
probably want to prepare one batch statement with a reasonable number
of statement in it (you'll have to test to find number that give the
best performances, but I would typically start with say 50-100 and see
if the performance are good enough) and reuse that to insert the data.

The other reason why breaking the insert into smallish batches is a
good idea is that it allows you to parallelize the insert using
multiple threads. And you need to parallelize if you want to get the
best out of C*.

--
Sylvain

>
> Maybe I can try small example first, just to see if it works at all.
>
>
>
>
>
> From: Derek Williams [mailto:derek@fyrie.net]
> Sent: Tuesday, July 10, 2012 7:19 PM
> To: user@cassandra.apache.org
> Subject: Re: help using org.apache.cassandra.cql3
>
>
>
> On Tue, Jul 10, 2012 at 3:04 PM, Leonid Ilyevsky <lilyevsky@mooncapital.com>
> wrote:
>
> I am trying to use the org.apache.cassandra.cql3 package. Having problem
> connecting to the server using ClientState.
>
> I was not sure what to put in the credentials map (I did not set any
> users/passwords on my server), so I tried setting empty strings for
> "username" and "password", setting them to bogus values, passing null to the
> login method - there was no difference.
>
> It does not complain at the login(), but then it complains about
> setKeyspace(<my keyspace>), saying that the specified keyspace does not
> exist (it obviously does exist).
>
> The configuration was loaded from cassandra.yaml used by the server.
>
>
>
> I did not have any problem like this when I used
> org.apache.cassandra.thrift.Cassandra.Client .
>
>
>
> What am I doing wrong?
>
>
>
> I think that package just contains server classes. Everything you need
> should be in org.apache.cassandra.thrift.
>
>
>
> To use cql3 I just use the client methods 'execute_cql_query',
> 'prepare_cql_query' and 'execute_prepared_cql_query', after setting cql
> version to '3.0.0'.
>
>
>
>
>
> --
>
> Derek Williams
>
>
>
>
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This email, along with any attachments, is confidential and may be legally privileged or otherwise
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of this email is strictly prohibited and may be in violation of law. If you are not the intended
recipient, any disclosure, copying, forwarding or distribution of this email is strictly prohibited
and this email and any attachments should be deleted immediately.  This email and any attachments
do not constitute an offer to sell or a solicitation of an offer to purchase any interest
in any investment vehicle sponsored by Moon Capital Management LP ("Moon Capital"). Moon Capital
does not provide legal, accounting or tax advice. Any statement regarding legal, accounting
or tax matters was not intended or written to be relied upon by any person as advice. Moon
Capital does not waive confidentiality or privilege as a result of this email.

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