Re: pgbench stats per script & other stuff

Fabien COELHO <coelho@cri.ensmp.fr>

From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Michael Paquier <michael.paquier@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2016-03-04T18:53:38Z
Lists: pgsql-hackers

Attachments

>> That is why the "fs" variable in process_file is declared "static", and why
>> I wrote "some hidden awkwarness".
>>
>> I did want to avoid a malloc because then who would free the struct?
>> addScript cannot to it systematically because builtins are static. Or it
>> would have to create an on purpose struct, but I then that would be more
>> awkwarness, and malloc/free to pass arguments between functions is not
>> efficient nor very elegant.
>>
>> So the "static" option looked like the simplest & most elegant version.
>
> Surely that trick breaks if you have more than one -f switch, no?  Oh, I
> see what you're doing: you only use the command list, which is
> allocated, so it doesn't matter that the rest of the struct changes
> later.

The two fields that matter (desc and commands) are really copied into 
sql_scripts, so what stays in the is overriden if used another time.

> I'm not concerned about freeing the struct; what's the problem with it
> surviving until the program terminates?

It is not referenced anywhere so it is a memory leak.

> If somebody specifies thousands of -f switches, they will waste a few 
> bytes with each, but I'm hardly concerned about a few dozen kilobytes 
> there ...

Ok, so you prefer a memory leak. I hate it on principle.

Here is a v23 with a memory leak anyway.

-- 
Fabien.

Commits

  1. pgbench: Allow changing weights for scripts