Re: Performance of subselects

2009/3/9 Christian Schröder <cs@deriva.de>:
> Scott Marlowe wrote:
>>>
>>> you can run out of memory if too many connections try to use too much
>>> of it at the same time, that's why it is advisable to set work_mem per
>>> connection/query, should the connection/query require more.
>>>
>>
>> Definitely.
>>
>
> I understand why this is advisable; however, something inside me hates the
> idea to put this kind of database specific stuff inside an application. How
> about portability? Why does the application developer have to know about
> database internals? He knows sql, that should be sufficient.
> I have the (maybe naive) idea of a clear separation of database
> administration (including performance tuning) and application development.
> Is this idea completely wrong?

You can always use a different account for things that need big
work_mem (typically reporting queries etc.) and alter that user to
have a different work_mem.  That all the dev needs to know is which
account to use.  You can also set it by database if that's a better
fit.