PostgreSQL Functions
PHP Manual

pg_trace

Enable tracing a PostgreSQL connection

Description

bool pg_trace(
    string $filename,
    string $mode = "w",
    PgSql\Connectionnull $connection = null,
    int $trace_mode = 0
)

pg_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.

Parameters

filename

The full path and file name of the file in which to write the trace log. Same as in fopen.

mode

An optional file access mode, same as for fopen.

connection

An PgSql\Connection instance. When connection is null, the default connection is used. The default connection is the last connection made by pg_connect or pg_pconnect.

Warning

As of PHP 8.1.0, using the default connection is deprecated.

trace_mode

An optional trace mode with the following constants PGSQL_TRACE_SUPPRESS_TIMESTAMPS and PGSQL_TRACE_REGRESS_MODE

Return Values

Returns true on success or false on failure.

Changelog

Version Description
8.3.0 trace_mode has been added.
8.1.0 The connection parameter expects an PgSql\Connection instance now; previously, a resource was expected.
8.0.0 connection is now nullable.

Examples

Example #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;
}
?>

See Also

  • fopen
  • pg_untrace