It took 10 hours to compute the query without the index on
Once I created the index on lineitem.l_partkey, it took only 32 secs to
run the same query.  
After VACUUM ANALYZE it took 72 secs to run the query.
All the subsequent runs took under 3 seconds!

That's quite amazing!

I just checked  

-----Original Message-----
From: Mary Edie Meredith [mailto:[EMAIL PROTECTED] 
Sent: Monday, September 29, 2003 10:04 AM
To: Oleg Lebedev
Cc: Tom Lane; Jenny Zhang; pgsql-performance
Subject: RE: [PERFORM] TPC-R benchmarks

On Mon, 2003-09-29 at 07:35, Oleg Lebedev wrote:
> I left my TPC-R query #17 working over the weekend and it took 3988 
> mins ~ 10 hours to complete. And this is considering that I am using a

> TPC-R database created with a scale factor of 1, which corresponds to 
> ~1 GB of data. I am running RedHat 8.0 on a dual 1 GHz processor, 512 

Was this run with or without the l_partkey index that Jenny suggested? 

> Here is an excerpt from my postgresql.conf file (the rest of the 
> settings are commented out):
> #
> #     Shared Memory Size
> #
> shared_buffers = 16384                # 2*max_connections, min 16,
> 8KB each
> #
> #     Non-shared Memory Sizes
> #
> sort_mem = 32768
> #
> #     Optimizer Parameters
> #
> effective_cache_size = 32000  # typically 8KB each
> Any suggestions on how to optimize these settings?
> I agree with Jenny that declaring additional indexes on the TPC-R 
> tables may alter the validity of the benchmarks. Are there any 
> official TPC benchmarks submitted by PostgreSQL?

Actually, for the TPC-R you _are allowed to declare additional indexes. 
With TPC-H you are restricted to a specific set listed in the spec (an
index on l_partkey is allowed for both).

What you cannot do for either TPC-R or TPC-H is rewrite the SQL of the
query for the purposes of making the query run faster.

Sorry if I was unclear.

Valid TPC-R benchmark results are on the TPC web site:  

I do not see one for PostgreSQL.



Mary Edie Meredith <[EMAIL PROTECTED]>
Open Source Development Lab

> Thanks.
> Oleg
> -----Original Message-----
> From: Mary Edie Meredith [mailto:[EMAIL PROTECTED]
> Sent: Friday, September 26, 2003 10:12 AM
> To: Tom Lane
> Cc: Oleg Lebedev; Jenny Zhang; pgsql-performance
> Subject: Re: [PERFORM] TPC-R benchmarks
> The TPC-H/R rules allow only minor changes to the SQL that are 
> necessary due to SQL implementation differences. They do not allow 
> changes made to improve performance.  It is their way to test 
> optimizer's ability to recognize an inefficient SQL statement and do 
> the rewrite.
> The rule makes sense for the TPC-H, which is supposed to represent 
> ad-Hoc query.  One might argue that for TPC-R, which is suppose to 
> represent "Reporting" with pre-knowledge of the query, that re-write 
> should be allowed. However, that is currently not the case. Since the 
> RDBMS's represented on the TPC council are competing with TPC-H, their

> optimizers already do the re-write, so (IMHO) there is no motivation 
> to relax the rules for the TPC-R.
> On Thu, 2003-09-25 at 21:28, Tom Lane wrote:
> > Oleg Lebedev <[EMAIL PROTECTED]> writes:
> > > Seems like in your case postgres uses an i_l_partkey index on
> > > lineitem table. I have a foreign key constraint defined between
> > > lineitem and part table, but didn't create an special indexes.
> > > is my query plan:
> > 
> > The planner is obviously unhappy with this plan (note the large cost
> > numbers), but it can't find a way to do better.  An index on 
> > lineitem.l_partkey would help, I think.
> > 
> > The whole query seems like it's written in a very inefficient 
> > fashion;
> > couldn't the estimation of '0.2 * avg(l_quantity)' be amortized 
> > across
> > multiple join rows?  But I dunno whether the TPC rules allow for
> > significant manual rewriting of the given query.
> > 
> >                     regards, tom lane
> > 
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