Re: psql metaqueries with \gexec

On Mon, Feb 22, 2016 at 11:30 AM, Corey Huinker <corey(dot)huinker(at)gmail(dot)com>
wrote:

> On Mon, Feb 22, 2016 at 10:08 AM, Daniel Verite <daniel(at)manitou-mail(dot)org>
> wrote:
>
>> Corey Huinker wrote:
>>
>> > ...and query text visibility, and result visibility, and error handling,
>> > etc. In this case, we're leveraging the psql environment we'd already
>> set
>> > up, and if there's an error, \set ECHO queries shows us the errant SQL
>> as
>> > if we typed it ourselves..
>>
>> BTW, about error handling, shouldn't it honor ON_ERROR_STOP ?
>>
>> With the patch when trying this:
>>
>> => set ON_ERROR_STOP on
>> => select * from (values ('select 1/0', 'select 1/0')) AS n \gexec
>>
>> it produces two errors:
>> ERROR: division by zero
>> ERROR: division by zero
>>
>> I'd rather have the execution stop immediately after the first error,
>> like it's the case with successive queries entered normally via the
>> query buffer:
>>
>> => \set ON_ERROR_STOP on
>> => select 1/0; select 1/0;
>> ERROR: division by zero
>>
>> as opposed to:
>>
>> => \set ON_ERROR_STOP off
>> => select 1/0; select 1/0;
>> ERROR: division by zero
>> ERROR: division by zero
>>
>>
> Yes, I would like it to honor ON_ERROR_STOP. I'll look into that.
>
>
Well, that was easy enough. Turns out that pset.on_error_stop is checked in
MainLoop, whereas the other pset.on_* vars are checked in SendQuery().

My original idea had been to push each cell into a in-memory temp file
handle and call MainLoop() on each. Pavel suggested that temp files of any
sort were a bad idea, hence using SendQuery instead. It's probably for the
best.

# select 'select 1,2,3', 'select 1/0', 'select 4,5,6'
... # \gexec
?column? | ?column? | ?column?
----------+----------+----------
1 | 2 | 3
(1 row)

Time: 0.151 ms
ERROR: 22012: division by zero
LOCATION: int4div, int.c:719
Time: 0.528 ms
?column? | ?column? | ?column?
----------+----------+----------
4 | 5 | 6
(1 row)

Time: 0.139 ms
Time: 0.595 ms
# \set ON_ERROR_STOP 1
# select 'select 1,2,3', 'select 1/0', 'select 4,5,6' \gexec
?column? | ?column? | ?column?
----------+----------+----------
1 | 2 | 3
(1 row)

Time: 0.137 ms
ERROR: 22012: division by zero
LOCATION: int4div, int.c:719
Time: 0.165 ms
Time: 0.284 ms

Does \set ON_ERROR_STOP mess up regression tests? If not, I'll add the test
above (minus the \set VERBOSITY verbose-isms) to the regression.

In the mean time, update patch attached.