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
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
> MB RAM.
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
> -----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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