Re: four minor proposals for 9.5

2014-03-20 5:36 GMT+01:00 Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>:

> On Wed, Mar 19, 2014 at 9:04 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> > Hello
> >
> > I wrote a few patches, that we use in our production. These patches are
> > small, but I hope, so its can be interesting for upstream:
> >
> > 1. cancel time - we log a execution time cancelled statements
> >
> > 2. fatal verbose - this patch ensure a verbose log for fatal errors. It
> > simplify a investigation about reasons of error.
> >
> > 3. relation limit - possibility to set session limit for maximum size of
> > relations. Any relation cannot be extended over this limit in session,
> when
> > this value is higher than zero. Motivation - we use lot of queries like
> > CREATE TABLE AS SELECT .. , and some very big results decreased a disk
> free
> > space too much. It was high risk in our multi user environment.
> Motivation
> > is similar like temp_files_limit.
>
> So if there is error on reaching max threshold size, won't it loose all
> data or
> is that expected?
>

Exception is expected

>
> Also I think it might not be applicable for all table inserts, as normally
> checkpointer/bgrwriter flushes data, so you might not be able to estimate
> size immediately when your SQL statement is executing.
>
> Won't it better to have LIMIT Rows in Select statement or generically
> have table level option for Max Rows?
>

It significantly harder to expect N for LIMIT - there are lot of varlena
types, so sometimes you can be too strict, sometimes you can be too tolerant

>
>
> With Regards,
> Amit Kapila.
> EnterpriseDB: http://www.enterprisedb.com
>