(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
pg_trace — Enable tracing a PostgreSQL connection
$filename,$mode = "w",$connection = null,$trace_mode = 0pg_trace() enables tracing of the PostgreSQL frontend/backend communication to a file. To fully understand the results, one needs to be familiar with the internals of PostgreSQL communication protocol.
For those who are not, it can still be useful for tracing errors in queries sent to the server, you could do for example grep '^To backend' trace.log and see what queries actually were sent to the PostgreSQL server. For more information, refer to the » PostgreSQL Documentation.
filenameThe full path and file name of the file in which to write the trace log. Same as in fopen().
modeAn optional file access mode, same as for fopen().
connectionПримірник
PgSql\Connection. Якщо параметр
connection — null, то виконується стандартне
з'єднання, тобто останнє, виконане функцією pg_connect()
або pg_pconnect(). 
Починаючи з PHP 8.1.0, використання стандартного з'єднання є застарілим.
trace_mode
       An optional trace mode with the following constants
       PGSQL_TRACE_SUPPRESS_TIMESTAMPS and
       PGSQL_TRACE_REGRESS_MODE
      
| Версія | Опис | 
|---|---|
| 8.3.0 | trace_modehas been added. | 
| 8.1.0 | Тепер параметр connectionмає бути примірником
  PgSql\Connection. Раніше очікувався resource. | 
| 8.0.0 | connectionis now nullable. | 
Приклад #1 pg_trace() example
<?php
$pgsql_conn = pg_connect("dbname=mark host=localhost");
if ($pgsql_conn) {
   pg_trace('/tmp/trace.log', 'w', $pgsql_conn);
   pg_query("SELECT 1");
   pg_untrace($pgsql_conn);
   // Now /tmp/trace.log will contain backend communication
} else {
   print pg_last_error($pgsql_conn);
   exit;
}
?>
