pg_get_result()

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

取得异步查询结果

说明

pg_get_result([resource $connection]): resource

pg_get_result()取得执行pg_send_query()而得到的查询结果资源。pg_send_query()可以向 PostgreSQL 发送多个查询，pg_get_result()则用来逐个得到查询结果。返回值为查询结果资源号。如果没有更多查询结果，则返回FALSE。

There is no way to poll/wait for a notification to come in. You either have to enter a busy loop or sleep. Both options are horrible. It would be nice for PHP to provide access to PQsocket so one could select() on the socket connection. This is how it's done from C or Perl.

It might seem that after calling pg_get_result() upon sending just a single query, the connection will not be busy. The correct way is, though, to call extra pg_get_result() in a loop until it returns false [1].
<?php
$conn = pg_connect('...', PGSQL_CONNECT_FORCE_NEW);
for ($i = 0; $i < 10000; $i++) {
  $query = 'erroneous query';
  if (pg_connection_busy($conn)) {
    fprintf(STDERR, "Connection is busy\n");
    exit(1);
  }
  pg_send_query($conn, $query);
  $res = pg_get_result($conn);
  if ($res === false) {
    fprintf(STDERR, "A result was expected\n");
    exit(1);
  }
  /* The following does not seem necessary for good queries, but is vital for erroneous queries.
    Commenting the loop out leads to this script fail with the "Connection is busy" error. */
  while (pg_get_result($conn));
  // result processing...
}
?>
See http://www.postgresql.org/message-id/flat/gtitqq$26l3$1@news.hub.org#gtitqq$26l3$1@news.hub.org and https://bugs.php.net/bug.php?id=52750 for detailed information.
[1] Or, even better, use an asynchronous connection since PHP 5.6.

To have a a simple wait output with async queries you can use the pg_connection_busy command:
<?php
$dbh = pg_connect("host=XXX user=XXX password=XXX dbname=XXX");
if (!$dbh)
{
  print "Failed to connect";
  exit;
}
$query = "SELECT pg_sleep(10)";
if (!pg_connection_busy($dbh))
{
  $sent = pg_send_query($dbh, $query);
  print "Sent query, waiting: ";
  while (pg_connection_busy($dbh)
  {
    print ".";
    flush();
  }
  $res = pg_get_result($dbh);
  print "<br>"; // or \n
  print "Result is: $res";
}
pg_close($dbh);
?>

william at 25thandClement dot com said: "There is no way to poll/wait for a notification to come in. .."
Yes, there is. If there is a query in progress, pg_get_result() will block and return the result of that query when it's complete.