pg_send_query

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_send_query Ejecuta una consulta PostgreSQL asíncrona

Descripción

pg_send_query(PgSql\Connection $connection, string $query): int|bool

pg_send_query() envía una consulta o varias consultas de manera asíncrona a la conexión connection. A diferencia de pg_query(), puede enviar varias consultas al mismo tiempo al servidor PostgreSQL y obtener los resultados uno por uno utilizando pg_get_result().

La ejecución del script no se bloquea durante la ejecución de las consultas. Se puede utilizar pg_connection_busy() para verificar si la conexión está ocupada (es decir, si la consulta se está ejecutando). Las consultas pueden ser canceladas con pg_cancel_query().

Aunque se puedan enviar varias consultas al mismo tiempo, no es posible enviar varias consultas en una conexión ocupada. Si se envía una consulta cuando la conexión está ocupada, esperará a que la consulta anterior termine y perderá todos sus resultados.

Parámetros

connection

El recurso de conexión de la base de datos PostgreSQL.

query

La consulta o las consultas SQL a ser ejecutadas.

Los datos contenidos en la consulta deben ser escaped correctamente.

Valores devueltos

Devuelve true en caso de éxito, false o 0 en caso de fallo. Utilice pg_get_result() para determinar el resultado de la consulta.

Historial de cambios

Versión Descripción
8.1.0 The connection parameter expects an PgSql\Connection instance now; previously, a recurso was expected.

Ejemplos

Ejemplo #1 Ejemplo con pg_send_query()

<?php
$dbconn
= pg_connect("dbname=publisher") or die("Conexión imposible");

if (!
pg_connection_busy($dbconn)) {
pg_send_query($dbconn,"select * from autores; select count(*) from autores;");
}

$res1 = pg_get_result($dbconn);
echo
"Primera llamada a pg_get_result() : $res1\n";
$rows1 = pg_num_rows($res1);
echo
"$res1 tiene $rows1 registros\n\n";

$res2 = pg_get_result($dbconn);
echo
"Segunda llamada a pg_get_result() : $res2\n";
$rows2 = pg_num_rows($res2);
echo
"$res2 tiene $rows2 registros\n";
?>

El resultado del ejemplo sería:

Primera llamada a pg_get_result() : Resource id #3
Resource id #3 tiene 3 registros

Segunda llamada a pg_get_result() : Resource id #4
Resource id #4 tiene 1 registros

Ver también

add a note

User Contributed Notes 6 notes

up
0
rw burgholzer is name at deq dot virginia dot gov
15 years ago
Regarding the failure to process them all now, then retrieve the results later, I found that all queries would return successfully if I added a further condition to your while loop in the "stack_query()" method.

By adding:
&& (pg_transaction_status($conn) === PGSQL_TRANSACTION_IDLE ) )

Every query executed with no errors.

<?php
$conn
= pg_connect("dbname=dbname host=localhost user=psql ");
if (
$conn === FALSE)
exit(
"Can't connect to db");

$q = array();
// send some queries
foreach (range(0, 50) as $i)
stack_query($q, $conn, "SELECT 'query $i' AS str;");
// receive them
while (true)
{
$left = stack_query($q, $conn);
echo
"$left left... ";
$result = pg_get_result($conn);
if (
$left == 0 && $result === FALSE)
break;
$row = pg_fetch_assoc($result);
// depending on race conditions, you wont get all your original queries here.
echo "got $row[str]\n";
}

function
stack_query(&$queries, $conn, $sql = FALSE)
{
if (
$sql !== FALSE)
$queries[] = $sql;
while (
count($queries) && !pg_connection_busy($conn) && (pg_transaction_status($conn) === PGSQL_TRANSACTION_IDLE ) )
pg_send_query($conn, array_shift($queries));
return
count($queries) + (pg_connection_busy($conn) ? 1 : 0);
}
?>
up
0
Mikewithme at yahoo dot com
21 years ago
Due to a bug, OLD API does not available with PHP 4.2.0 and 4.2.1.

PHP 4.2.2 will support OLD API again and will be kept long enough.

New API will be available PHP 4.2.0 to later versions.
yohgaki at php dot net
19-Jun-2002 04:00
Due to a bug, PHP 4.2.0 and 4.2.1 does not support pg_lo_import() old API. It's fixed in PHP 4.2.2.

BTW, new API will be always available from PHP 4.2.0 to later versions. Older API will be kept long enough, also.
ceco at noxis dot net
15-May-2002 09:08
it works for me (php-4.2.1)

not like this

int pg_lo_import ( string pathname [, resource connection])

but
int pg_lo_import ( resource connection, string pathname )

don't know the reason
up
-1
moodsey211 at gmail dot com
14 years ago
pg_send_query would not stop your script from executing but it would stop the script from exiting.

Example:

<?php
$con
= pg_connect('dbname=payroll');
pg_send_query('SELECT process_payroll()'); // Where process_payroll is a super long process
?>

You would still need to wait for the query to finish before the any display would be sent to the browser. And surprisingly, unlike pg_query this script would not generate the Maximum execution time error.
up
-1
Ron Howard
22 years ago
If there is an error in one of your queries, the queries following it will not get executed, and there will *not* be an error message displayed. The only way I can think of to determine if an SQL error happened is to use pg_trace.

Example:

pg_send_query($connection,
"SELECT id FROM users;
SELECT * FROM customers;
[INVALID-SQL-STATEMENT];
SELECT name FROM countries;");

while ($result = pg_get_result($connection))
$results[] = $result;

The $results array will only have two items in it.
up
-2
Likeyouover others at hotmail dot com
21 years ago
<?php
// --------- OPEN CONN ---

$conn = pg_connect("host='127.0.0.1' dbname='test' user='usertest' password='passtest'");

// --------- OPEN FILE ---

$fp = fopen('logo.gif', "r");
$buffer = fread($fp, filesize('logo.gif'));
fclose($fp);

// --------- CREATE - INSERT OID ---

pg_exec($conn, "begin");

$oid = pg_locreate($conn);

$rs = pg_exec($conn,"INSERT INTO test(tipo, images) VALUES('A1', $oid);");
$handle = pg_loopen ($conn, $oid, "w");

pg_lowrite ($handle, $buffer);
pg_loclose ($handle);

pg_exec($conn, "commit");

// --------- OPEN - INSERT OID ---

$rs = pg_exec($conn, "SELECT images FROM test WHERE tipo = 'A1';");
$row = pg_fetch_row($rs, 0);

pg_exec($conn, "begin");
$loid = pg_loopen($conn, $row[0], "r");

header("Content-type: image/gif");

pg_loreadall($loid);
pg_loclose($loid);

pg_exec ($conn, "commit");

// --------- UNLINK OID ---

pg_exec($conn, "begin");

$loid = $row[0];
pg_lounlink($conn, $loid);

pg_exec ($conn, "commit");

// --------- DELETE OID ---

pg_exec($conn, "DELETE FROM test WHERE tipo = 'A1';");

// --------- CLOSE CONN ---

pg_close();
?>
up
-5
vincentdephily
19 years ago
Note that if you send a query without calling pg_get_result() for the previous one (supposing it has finished and the connection is not busy), the previous query will get discarded.

See for yourself (tested on php4.4.0, postgres8.0.4, Linux/FreeBSD) :
<?
$conn
= pg_connect("dbname=template1 host=localhost user=pgsql");
if (
$conn === FALSE)
exit(
"Can't connect to db");

$q = array();
// send some queries
foreach (range(0, 500) as $i)
stack_query($q, $conn, "SELECT 'query $i' AS str;");
// receive them
while (true)
{
$left = stack_query($q, $conn);
echo
"$left left... ";
$result = pg_get_result($conn);
if (
$left == 0 && $result === FALSE)
break;
$row = pg_fetch_assoc($result);
// depending on race conditions, you wont get all your original queries here.
echo "got $row[str]\n";
}

function
stack_query(&$queries, $conn, $sql = FALSE)
{
if (
$sql !== FALSE)
$queries[] = $sql;
while (
count($queries) && !pg_connection_busy($conn))
pg_send_query($conn, array_shift($queries));
return
count($queries) + (pg_connection_busy($conn) ? 1 : 0);
}
?>

You will have to write a higher level of abstraction if you want a "send all queries now, receive them later" behaviour.
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