pg_send_query

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

pg_send_query — Envia consulta assíncrona

Descrição

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

pg_send_query() envia uma consulta ou consultas de forma assíncrona para a connection. Ao contrário de pg_query(), ele pode enviar múltiplas consultas de uma vez ao PostgreSQL e obter os resultados um por um usando pg_get_result().

A execução do script não é bloqueada enquanto as consultas estão em execução. Use pg_connection_busy() para verificar se a conexão está ocupada (ou seja, a consulta está em execução). As consultas podem ser canceladas usando pg_cancel_query().

Embora o usuário possa enviar diversas consultas de uma só vez, diversas consultas não podem ser enviadas em uma conexão ocupada. Se uma consulta for enviada enquanto a conexão estiver ocupada, ela aguardará até que a última consulta termine e descarta todos os seus resultados.

Parâmetros

connection

Uma instância de PgSql\Connection.

query

A instrução ou instruções SQL a serem executadas.

Os dados dentro da consulta devem ser escapados corretamente.

Valor Retornado

Retorna true em caso de sucesso, false ou 0 em caso de falha. Use pg_get_result() para determinar o resultado da consulta.

Registro de Alterações

Versão	Descrição
8.1.0	O parâmetro `connection` agora espera uma instância de PgSql\Connection; anteriormente, um resource era esperado.

Exemplos

Exemplo #1 Exemplo de pg_send_query()

<?php
  $dbconn = pg_connect("dbname=publisher") or die("Não foi possivel conectar");

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

  $res1 = pg_get_result($dbconn);
  echo "Primeira chamada a pg_get_result(): $res1\n";
  $rows1 = pg_num_rows($res1);
  echo "$res1 possui $rows1 registro(s)\n\n";

  $res2 = pg_get_result($dbconn);
  echo "Segunda chamada a pg_get_result(): $res2\n";
  $rows2 = pg_num_rows($res2);
  echo "$res2 possui $rows2 registro(s)\n";
?>

O exemplo acima produzirá:

Primeira chamada a pg_get_result(): Resource id #3
Resource id #3 possui 3 registro(s)

Segunda chamada a pg_get_result(): Resource id #4
Resource id #4 possui 1 registro(s)

Veja Também

pg_query() - Executa uma consulta
pg_cancel_query() - Cancela uma consulta assíncrona
pg_get_result() - Obtém o resultado da consulta assíncrona
pg_connection_busy() - Obtém se conexão está ocupada ou não

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User Contributed Notes 6 notes

down

rw burgholzer is name at deq dot virginia dot gov ¶

14 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);
}
?>

down

Mikewithme at yahoo dot com ¶

20 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

down

-1

moodsey211 at gmail dot com ¶

13 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.

down

-1

Ron Howard ¶

21 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.

down

-2

Likeyouover others at hotmail dot com ¶

20 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();
?>

down

-5

vincentdephily ¶

18 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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