Re: pgbench -f and vacuum

> On 14 December 2014 at 04:39, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>
>> Tatsuo Ishii <ishii(at)postgresql(dot)org> writes:
>> > Currently pgbench -f (run custom script) executes vacuum against
>> > pgbench_* tables before stating bench marking if -n (or --no-vacuum)
>> > is not specified. If those tables do not exist, pgbench fails. To
>> > prevent this, -n must be specified. For me this behavior seems insane
>> > because "-f" does not necessarily suppose the existence of the
>> > pgbench_* tables. Attached patch prevents pgbench from exiting even
>> > if those tables do not exist.
>>
>> I don't particularly care for this approach. I think if we want to
>> do something about this, we should just make -f imply -n. Although
>> really, given the lack of complaints so far, it seems like people
>> manage to deal with this state of affairs just fine. Do we really
>> need to do anything?
>>
>>
>>
> I also find this weird vacuum non existing tables rather bizarre. I think
> the first time I ever used pgbench I was confronted by the pgbench* tables
> not existing, despite the fact that I was trying to run my own script.
> Looking at --help it mentioned nothing about the pgbench_* tables, so I was
> pretty confused until I opened up the online docs.
>
> I'm not really a fan of how this is done in the proposed patch, I'd vote
> for either skipping vacuum if -f is specified, or just doing a database
> wide vacuum in that case. Though, that might surprise a few people, so
> maybe the first option is better.

Problem with "-f implies -n" approach is, it breaks backward
compatibility. There are use cases using custom script *and* pgbench_*
tables. For example the particular user wants to use the standard
pgbench tables and is not satisfied with the built in scenario. I know
at least one user does this way.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp