Hi Martin:
 
We tried the Recycle pipeline for Skyserver on the Oct2010-SP1 release. And, we didn't see any problems, though the testing was fairly short..... One thing we did notice is that queries against defined views do not seem to benefit from the recycler pipeline at all. Running a simple query, select distinct x from y, back to back seem to take just as long each time. So, I don't think the Recycler pipeline for Skyserver is effective on views.
 
We set up a new Recycler pipeline using the Feb-2010 default pipeline by adding "recycle" between "deadcode" and "reduce". Unfotunately, we were getting erratic results after running a few queries. For example, we ran some simple queries like select distinct x from y which returned couple dozen rows. After running a few other queries, the same select distinct x from y returned empty result set. We restarted the MonetDB server and got expected results for a while. But, after running some more quries, the simple select distinct x from y started to return null set. So, I think there are some issues with using recycle optimizer with the Feb-2010 default pipeline, at least the way I have used it. Or, does the recycler pipeline need to be set up with a different set of Feb-2010 optimizers than what I have included?
One of the reasons that we are looking at using the recyler option is because we saw performance degradation going from the Nov-2009SP2 to Oct-2010SP1 for queries on views though we saw many improvements, in terms of performance and resource use, from upgrading. Is this a bug or are queries on views treated differently by design? Thanks!
 
Henry
On Thu, Mar 3, 2011 at 2:35 PM, Martin Kersten <Martin.Kersten@cwi.nl> wrote:
Hi Henry

We would love to here experiences in using the recycler.

regards, Martin Kersten
On 3/3/11 11:00 PM, Henry Addington wrote:
> Hello:
> I understand some of the optimizers/pipelines are experimental as indicated in the monetdb5.conf file. Has anyone used the Recycle pipeline for Skyserver? Would you mind sharing your experience, in terms of performance improvement and whether it can bet
> used in a production environment? We are using the Oct2010-SP1 release for a db that is read-only. I would guess if there are issues, I would think the problems would likely show up in read/write systems. Any feedback would be appreciated....
> It looks like the Recycle pipeline for Skyserver pipeline is based on the Nov-2009 pipeline. Has anyone tried the recycler optimizer with the Feb2010 default pipeline? I was going to add "recycle" between "deadcode" and "reduce" in the default pipeline and
> see if it would work. Thanks.
> Henry
>
>
>
> ------------------------------------------------------------------------------
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> This paper provides an overview of data connectivity, details
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> solutions. http://p.sf.net/sfu/progress-d2d
>
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What You Don't Know About Data Connectivity CAN Hurt You
This paper provides an overview of data connectivity, details
its effect on application quality, and explores various alternative
solutions. http://p.sf.net/sfu/progress-d2d
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