Re: R: Very slow bytea data extraction

Lists: pgsql-performance
From: "msmbarabino(at)virgilio(dot)it" <msmbarabino(at)virgilio(dot)it>
To: pgsql-performance(at)postgresql(dot)org
Subject: R: Very slow bytea data extraction
Date: 2007-02-23 12:19:56
Message-ID: 110ee8b13e5.msmbarabino@virgilio.it
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-performance

Thanks for your reply,

>Is it in executing the query (what does
EXPLAIN ANALYSE show)?

Here is the output of explain analyze SELECT *
FROM "FILE"

"Seq Scan on "FILE" (cost=0.00..1.36 rows=36 width=235)
(actual time=0.023..0.107 rows=36 loops=1)"

>How are you accessing
the database: odbc,jdbc,other?
>Does it do this with psql too?

The
problem is the same when I access the db with jdbc, pgAdmin and even
psql

Massimo


From: Richard Huxton <dev(at)archonet(dot)com>
To: "msmbarabino(at)virgilio(dot)it" <msmbarabino(at)virgilio(dot)it>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: R: Very slow bytea data extraction
Date: 2007-02-23 14:39:21
Message-ID: 45DEFC99.4070408@archonet.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-performance

msmbarabino(at)virgilio(dot)it wrote:
> Thanks for your reply,
>
>
>> Is it in executing the query (what does
> EXPLAIN ANALYSE show)?
>
> Here is the output of explain analyze SELECT *
> FROM "FILE"
>
> "Seq Scan on "FILE" (cost=0.00..1.36 rows=36 width=235)
> (actual time=0.023..0.107 rows=36 loops=1)"

If you look at the "actual time" it's completing very quickly indeed. So
- it must be something to do with either:
1. Fetching/formatting the data
2. Transferring the data to the client.

What happens if you only select half the rows? Does the time to run the
select halve?

--
Richard Huxton
Archonet Ltd


From: "Merlin Moncure" <mmoncure(at)gmail(dot)com>
To: "msmbarabino(at)virgilio(dot)it" <msmbarabino(at)virgilio(dot)it>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: R: Very slow bytea data extraction
Date: 2007-02-23 16:35:42
Message-ID: b42b73150702230835l25324a39xae5bce6c48977a3c@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-performance

On 2/23/07, msmbarabino(at)virgilio(dot)it <msmbarabino(at)virgilio(dot)it> wrote:
> Thanks for your reply,
>
>
> >Is it in executing the query (what does
> EXPLAIN ANALYSE show)?
>
> Here is the output of explain analyze SELECT *
> FROM "FILE"
>
> "Seq Scan on "FILE" (cost=0.00..1.36 rows=36 width=235)
> (actual time=0.023..0.107 rows=36 loops=1)"
>
>
> >How are you accessing
> the database: odbc,jdbc,other?
> >Does it do this with psql too?
>
> The
> problem is the same when I access the db with jdbc, pgAdmin and even
> psql

are you getting the data from the local box or from a remote site?
also explain analyze is showing nothing slow but you did not post the
enitre output. also, try the \timing switch in psql.

merlin