Re: query hangs

On 10 June 2010 18:05, AI Rumman <rummandba(at)gmail(dot)com> wrote:

> Could you please give me the link for cursor- How to use it?
>
>
> On Thu, Jun 10, 2010 at 6:28 PM, Kevin Grittner <
> Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
>
>> AI Rumman wrote:
>>
>> >> Merge Left Join (cost=9500.30..101672.51 rows=2629549 width=506)
>>
>> > And the query does not return data though I have been waiting for
>> > 10 mins.
>> >
>> > Do you have any idea ?
>>
>> Unless you use a cursor, PostgreSQL interfaces typically don't show
>> any response on the client side until all rows have been received and
>> cached on the client side. That's estimated to be over 2.6 million
>> rows in this case. That can take a while.
>>
>> You might want to use a cursor....
>>
>>

If you are using psql client, using FETCH_COUNT to a small value will allow
you to achieve cursor behaviour. psql starts returning batches of
FETCH_COUNT number of rows .

E.g. \set FETCH_COUNT 1
will start fetching and displaying each row one by one.

-Kevin
>>
>
>