delayed input

#1

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

#2

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
<elmongui (AT) cs (DOT) purdue.edu> wrote:

Quote:

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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#3

Hicham G. Elmongui wrote:

Quote:

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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#4

Use a cursor...

Quote:

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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#5

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" <elmongui (AT) cs (DOT) purdue.edu> wrote

Quote:

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

#6

Hicham G. Elmongui wrote:

Quote:

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

#7

On Tue, Oct 19, 2004 at 01:44:34PM -0500, Hicham G. Elmongui wrote:

Quote:

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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#8

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" <alvherre (AT) dcc (DOT) uchile.cl> wrote

Quote:

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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delayed input

comp.databases.postgresql.general comp.databases.postgresql.general

delayed input - 10-19-2004 , 11:10 AM

Re: delayed input - 10-19-2004 , 11:28 AM

Re: delayed input - 10-19-2004 , 11:41 AM

Re: delayed input - 10-19-2004 , 11:43 AM

Re: delayed input - 10-19-2004 , 01:44 PM

Re: delayed input - 10-19-2004 , 02:17 PM

Re: delayed input - 10-19-2004 , 02:19 PM

Re: delayed input - 10-22-2004 , 03:21 PM