Re: pgbench unusable after crash during pgbench

Thom Brown <thom(at)linux(dot)com> writes:
> On 19 November 2015 at 16:11, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> The only explanation I can think of here is that pgbench on startup
>> queries one of the tables to figure out the scale factor, and it seems
>> to be coming up with scaling factor 0, suggesting that the table was
>> perhaps truncated. If the tables are unlogged, that's expected.
>> Otherwise, it sounds like a serious bug in recovery.

> Actually yes, that's something I appear to have omitted. I was using
> unlogged tables, which makes sense now.

> Even so, the errors generated are not at all helpful, and I would
> expect pgbench to handle this case explicitly.

Meh ... it's not very clear how to improve that. The ":scale" variable is
set from "select count(*) from pgbench_branches"; it's not immediately
obvious that zero should not be an allowed result. Then the :scale value
is used as the upper limit in a \setrandom script command, and the
complaint about that seems fairly on point.

I do agree that pgbench could do more in the way of showing you the script
command (and line number, maybe) that failed. Patches welcome.

regards, tom lane