Re: pgbench--new transaction type

On 20 June 2012 15:32, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> On 01.06.2012 03:02, Jeff Janes wrote:
>>
>> I've attached a new patch which addresses several of your concerns,
>> and adds the documentation.  The description is much longer than the
>> descriptions of other nearby options, which mostly just give a simple
>> statement of what they do rather than a description of why that is
>> useful.  I don't know if that means I'm starting a good trend, or a
>> bad one, or I'm just putting the exposition in the wrong place.
>>
>> In addition to showing the benefits of coding things on the server
>> side when that is applicable, it also allows hackers to stress parts
>> of the server code that are not easy to stress otherwise.
>
>
> As you mentioned in your original email over a year ago, most of this could
> be done as a custom script. It's nice to have another workload to test, but
> then again, there's an infinite number of workloads that might be
> interesting.
>
> You can achieve the same with this custom script:
>
> \set loops 512
>
> do $$ DECLARE  sum integer default 0; amount integer; account_id integer;
> BEGIN FOR i IN 1..:loops LOOP   account_id=1 + floor(random() * :scale);
> SELECT abalance into strict amount FROM pgbench_accounts WHERE aid =
> account_id;   sum := sum + amount; END LOOP; END; $$;
>
> It's a bit awkward because it has to be all on one line, and you don't get
> the auto-detection of scale. But those are really the only differences
> AFAICS.
>
> I think we would be better off improving pgbench to support those things in
> custom scripts. It would be nice to be able to write initialization steps
> that only run once in the beginning of the test. You could then put the
> "SELECT COUNT(*) FROM pgbench_branches" there, to do the scale
> auto-detection.

I'm sure Jeff submitted this because of the need for a standard test,
rather than the wish to actually modify pgbench itself.

Can I suggest that we include a list of standard scripts with pgbench
for this purpose? These can then be copied alongside the binary when
we do an install.

That way this patch can become a standard script, plus an entry in the
docs to list this.

We could even include scripts for the usual cases, to allow them to be
more easily viewed/copied/modified.

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