OCI8 2.0 introduced static DTrace probes that can be used on operating systems that support DTrace. See DTrace Dynamic Tracing for an overview of PHP and DTrace.
To enable DTrace support in PHP OCI8, build OCI8 as a shared
extension after setting PHP_DTRACE.
$ export PHP_DTRACE=yes $ pecl install oci8
Edit php.ini, set extension_dir to the directory with the created oci8.so and also enable the extension by adding:
extension=oci8.so
If you install PHP OCI8 from PECL using phpize and
configure (instead
of pecl), you will still need to set
PHP_DTRACE=yes. This is because
the --enable-dtrace option will be ignored by the
limited configure script of a PECL bundle.
See Installation of PECL extensions for general PECL installation instructions.
| Probe Name | Probe Description | Probe Arguments |
|---|---|---|
oci8-connect-entry |
Initiated by oci_connect(), oci_pconnect() and oci_new_connect(). Fires before database connection is established. | char *username, char *dbname, char *charset, long session_mode, int persistent, int exclusive |
oci8-connect-return |
Fires at the end of connection. | void *connection |
oci8-check-connection |
Fires if an Oracle error might have caused the connection to become invalid. | void *connection, char *client_id, int is_open, long errcode, unsigned long server_status |
oci8-sqltext |
Fires when oci_parse() is executed. | void *connection, char *client_id, void *statement, char *sql |
oci8-connection-close |
Fires when the connection to the database is completely destroyed. | void *connection |
oci8-error |
Fires if an Oracle error occurs. | int status, long errcode |
oci8-execute-mode |
Fires at oci_execute() to show the execution mode. | void *connection, char *client_id, void *statement, unsigned int mode |
These probes are useful for tracing OCI8 scripts.
The connection and statement are the pointers to internal structures used for tracking PHP connections and executed statements.
The client_id is the value set by oci_set_client_identifier().
Core PHP also has static probes. See DTrace Static Probes in Core PHP.
| Probe Name |
|---|
oci8-connect-expiry |
oci8-connect-lookup |
oci8-connect-p-dtor-close |
oci8-connect-p-dtor-release |
oci8-connect-type |
oci8-sesspool-create |
oci8-sesspool-stats |
oci8-sesspool-type |
These probes are useful for OCI8 maintainers. Refer to the OCI8 source code for arguments and to see when the will fire.
To list available probes, start a PHP process and then run:
# dtrace -l
The output will be similar to:
ID PROVIDER MODULE FUNCTION NAME [ . . . ] 17 phpoci22116 oci8.so php_oci_dtrace_check_connection oci8-check-connection 18 phpoci22116 oci8.so php_oci_do_connect oci8-connect-entry 19 phpoci22116 oci8.so php_oci_persistent_helper oci8-connect-expiry 20 phpoci22116 oci8.so php_oci_do_connect_ex oci8-connect-lookup 21 phpoci22116 oci8.so php_oci_pconnection_list_np_dtor oci8-connect-p-dtor-close 22 phpoci22116 oci8.so php_oci_pconnection_list_np_dtor oci8-connect-p-dtor-release 23 phpoci22116 oci8.so php_oci_do_connect oci8-connect-return 24 phpoci22116 oci8.so php_oci_do_connect_ex oci8-connect-type 25 phpoci22116 oci8.so php_oci_connection_close oci8-connection-close 26 phpoci22116 oci8.so php_oci_error oci8-error 27 phpoci22116 oci8.so php_oci_statement_execute oci8-execute-mode 28 phpoci22116 oci8.so php_oci_create_spool oci8-sesspool-create 29 phpoci22116 oci8.so php_oci_create_session oci8-sesspool-stats 30 phpoci22116 oci8.so php_oci_create_session oci8-sesspool-type 31 phpoci22116 oci8.so php_oci_statement_create oci8-sqltext
The Provider column values consist of phpoci and
the process id of the currently running PHP process.
The Function column refers to PHP's internal C implementation function names where each provider is located.
If a PHP process is not running, then no PHP probes will be shown.
This example shows the basics of the DTrace D scripting language.
Example #1 user_oci8_probes.d for tracing all user-level PHP OCI8 Static Probes with DTrace
#!/usr/sbin/dtrace -Zs
#pragma D option quiet
php*:::oci8-connect-entry
{
printf("%lld: PHP connect-entry\n", walltimestamp);
printf(" credentials=\"%s@%s\"\n", arg0 ? copyinstr(arg0) : "", arg1 ? copyinstr(arg1) : "");
printf(" charset=\"%s\"\n", arg2 ? copyinstr(arg2) : "");
printf(" session_mode=%ld\n", (long)arg3);
printf(" persistent=%d\n", (int)arg4);
printf(" exclusive=%d\n", (int)arg5);
}
php*:::oci8-connect-return
{
printf("%lld: PHP oci8-connect-return\n", walltimestamp);
printf(" connection=0x%p\n", (void *)arg0);
}
php*:::oci8-connection-close
{
printf("%lld: PHP oci8-connect-close\n", walltimestamp);
printf(" connection=0x%p\n", (void *)arg0);
}
php*:::oci8-error
{
printf("%lld: PHP oci8-error\n", walltimestamp);
printf(" status=%d\n", (int)arg0);
printf(" errcode=%ld\n", (long)arg1);
}
php*:::oci8-check-connection
{
printf("%lld: PHP oci8-check-connection\n", walltimestamp);
printf(" connection=0x%p\n", (void *)arg0);
printf(" client_id=\"%s\"\n", arg1 ? copyinstr(arg1) : "");
printf(" is_open=%d\n", arg2);
printf(" errcode=%ld\n", (long)arg3);
printf(" server_status=%lu\n", (unsigned long)arg4);
}
php*:::oci8-sqltext
{
printf("%lld: PHP oci8-sqltext\n", walltimestamp);
printf(" connection=0x%p\n", (void *)arg0);
printf(" client_id=\"%s\"\n", arg1 ? copyinstr(arg1) : "");
printf(" statement=0x%p\n", (void *)arg2);
printf(" sql=\"%s\"\n", arg3 ? copyinstr(arg3) : "");
}
php*:::oci8-execute-mode
{
printf("%lld: PHP oci8-execute-mode\n", walltimestamp);
printf(" connection=0x%p\n", (void *)arg0);
printf(" client_id=\"%s\"\n", arg1 ? copyinstr(arg1) : "");
printf(" statement=0x%p\n", (void *)arg2);
printf(" mode=0x%x\n", arg3);
}
This script uses the -Z option to
dtrace, allowing it to be run when there is no
PHP process executing. If this option were omitted the script
would immediately terminate when no PHP executable was running
because it knows none of the probes to be monitored are in
existence.
On multi-CPU machines the probe ordering might not appear to be sequential. This depends on which CPU was processing the probes, and how threads migrate across CPUs. Displaying probe time stamps helps reduce confusion.
The script traces all user-level PHP OCI8 static probe points throughout the duration of a running PHP script. Run the D script:
# ./user_oci8_probes.d
Run a PHP script or application. The monitoring D script will output each probe's arguments as it fires. For example, a simple PHP script that queries a table might produce the following trace output:
1381794982092854582: PHP connect-entry credentials="hr@localhost/pdborcl" charset="" session_mode=0 persistent=0 exclusive=0 1381794982183158766: PHP oci8-connect-return connection=0x7f4a7907bfb8 1381794982183594576: PHP oci8-sqltext connection=0x7f4a7907bfb8 client_id="Chris" statement=0x7f4a7907c2a0 sql="select * from employees" 1381794982183783706: PHP oci8-execute-mode connection=0x7f4a7907bfb8 client_id="Chris" statement=0x7f4a7907c2a0 mode=0x20 1381794982444344390: PHP oci8-connect-close connection=0x7f4a7907bfb8
When monitoring is complete, the D script can be terminated with a
^C.