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delayed input

P: n/a
I need to select all tuples from a table, but need them to be fetched with a
constant delay (say 1 sec) between every consecutive tuples.

The first idea that came up to my mind is to create a DelayedSeqScan
operator, and put delay before returning the scanned tuple.

Can I do this functionality using table functions?

Regards,
--h
Nov 23 '05 #1
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7 Replies


P: n/a
Why not do this on the client side? I'm just curious as to the benfit
of doing this on the server.

On Tue, 19 Oct 2004 11:10:58 -0500, Hicham G. Elmongui
<el******@cs.purdue.edu> wrote:
I need to select all tuples from a table, but need them to be fetched with a
constant delay (say 1 sec) between every consecutive tuples.

The first idea that came up to my mind is to create a DelayedSeqScan
operator, and put delay before returning the scanned tuple.

Can I do this functionality using table functions?

Regards,
--h


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Nov 23 '05 #2

P: n/a
Hicham G. Elmongui wrote:
I need to select all tuples from a table, but need them to be fetched with a
constant delay (say 1 sec) between every consecutive tuples.

The first idea that came up to my mind is to create a DelayedSeqScan
operator, and put delay before returning the scanned tuple.

Can I do this functionality using table functions?


Could you not just use a cursor and fetch each row in turn based on some
timer in your application?

--
Richard Huxton
Archonet Ltd

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Nov 23 '05 #3

P: n/a


Use a cursor...
I need to select all tuples from a table, but need them to be fetched
with a
constant delay (say 1 sec) between every consecutive tuples.

The first idea that came up to my mind is to create a DelayedSeqScan
operator, and put delay before returning the scanned tuple.

Can I do this functionality using table functions?

Regards,
--h

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Nov 23 '05 #4

P: n/a
I need this for a side project. Is there a way to do something like this:

SELECT *
FROM DelayedTable('tablename', 5);

DelayedTable provides me with one tuple every 5 seconds.
Regards,
--h

"Hicham G. Elmongui" <el******@cs.purdue.edu> wrote in message
news:cl***********@news.hub.org...
I need to select all tuples from a table, but need them to be fetched with a constant delay (say 1 sec) between every consecutive tuples.

The first idea that came up to my mind is to create a DelayedSeqScan
operator, and put delay before returning the scanned tuple.

Can I do this functionality using table functions?

Regards,
--h

Nov 23 '05 #5

P: n/a
Hicham G. Elmongui wrote:
I need this for a side project. Is there a way to do something like this:

SELECT *
FROM DelayedTable('tablename', 5);


No, at my knowledge you'll obtain the first tuple only when
the function exit.
Regards
Gaetano Mendola

Nov 23 '05 #6

P: n/a
On Tue, Oct 19, 2004 at 01:44:34PM -0500, Hicham G. Elmongui wrote:
I need this for a side project. Is there a way to do something like this:

SELECT *
FROM DelayedTable('tablename', 5);


You can probably build a sleep() function in C, and then use that to
cause delaying in a PL/pgSQL set-returning function. Something like

#include <postgres.h>
#include <fmgr.h>

PG_FUNCTION_INFO_V1(sleep);

Datum
sleep(PG_FUNCTION_ARGS)
{
int32 delay = PG_GETARG_INT32(0);
sleep(delay);
PG_RETURN_VOID();
}

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
La web junta la gente porque no importa que clase de mutante sexual seas,
tienes millones de posibles parejas. Pon "buscar gente que tengan sexo con
ciervos incendiándose", y el computador dirá "especifique el tipo de ciervo"
(Jason Alexander)
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Nov 23 '05 #7

P: n/a
Well, it seems that i have to build the scan operator myself. Even the
FunctionScan will make all the function calls and stores the result in a
tuuplestore. So, all the delay will be occured only at the first function
invocation.
--h


"Alvaro Herrera" <al******@dcc.uchile.cl> wrote in message
news:20*******************@dcc.uchile.cl...
On Tue, Oct 19, 2004 at 01:44:34PM -0500, Hicham G. Elmongui wrote:
I need this for a side project. Is there a way to do something like this:
SELECT *
FROM DelayedTable('tablename', 5);
You can probably build a sleep() function in C, and then use that to
cause delaying in a PL/pgSQL set-returning function. Something like

#include <postgres.h>
#include <fmgr.h>

PG_FUNCTION_INFO_V1(sleep);

Datum
sleep(PG_FUNCTION_ARGS)
{
int32 delay = PG_GETARG_INT32(0);
sleep(delay);
PG_RETURN_VOID();
}

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
La web junta la gente porque no importa que clase de mutante sexual seas,
tienes millones de posibles parejas. Pon "buscar gente que tengan sexo con
ciervos incendiándose", y el computador dirá "especifique el tipo de

ciervo" (Jason Alexander)
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Nov 23 '05 #8

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