There's an article "PHP Web Auditing, Authorization and Monitoring with Oracle Database" at www.oracle.com/technetwork/articles/dsl/php-web-auditing-171451.html which is all about using oci_set_client_identifier()
(PHP 5 >= 5.3.2, PHP 7, PHP 8, PECL OCI8 >= 1.4.0)
oci_set_client_identifier — Sets the client identifier
Sets the client identifier used by various database components to identify lightweight application users who authenticate as the same database user.
The client identifier is registered with the database when the next 'round-trip' from PHP to the database occurs, typically when an SQL statement is executed.
The identifier can subsequently be queried, for example
with SELECT SYS_CONTEXT('USERENV','CLIENT_IDENTIFIER')
FROM DUAL. Database administration views such
as V$SESSION will also contain the value. It
can be used with DBMS_MONITOR.CLIENT_ID_TRACE_ENABLE
for tracing and can also be used for auditing.
The value may be retained across page requests that use the same persistent connection.
connectionOracle 连接标识，由 oci_connect()，oci_pconnect()，或 oci_new_connect() 返回。
client_idUser chosen string up to 64 bytes long.
示例 #1 Setting the client identifier to the application user
<?php
// Find the application user's login name
session_start();
$un = my_validate_session($_SESSION['username']);
$c = oci_connect('myschema', 'welcome', 'localhost/XE');
// Tell Oracle who that user is
oci_set_client_identifier($c, $un);
// The next round-trip to the database will piggyback the identifier
$s = oci_parse($c, 'select mydata from mytable');
oci_execute($s);
// ...
?>一些 OCI8 函数会导致 Roundtrips. 对数据库来说当启用结果缓存时，查询可能不产生 Roundtrips。
There's an article "PHP Web Auditing, Authorization and Monitoring with Oracle Database" at www.oracle.com/technetwork/articles/dsl/php-web-auditing-171451.html which is all about using oci_set_client_identifier()