Can we have 2 'extension_dir' in php.ini?

Question

When I installed pdo-pgsql, the extension was installed into /usr/lib/php/extensions/no-debug-non-zts-20090626/ and thus not automatically loaded. In php.ini, I have extension_dir = "/usr/local/lib/php/extensions/no-debug-non-zts-20090626" already defined.

Snippet of php.ini

; Directory in which the loadable extensions (modules) reside.
extension_dir = "/usr/local/lib/php/extensions/no-debug-non-zts-20090626"
zend_extension = "/usr/local/IonCube/ioncube_loader_lin_5.3.so"
zend_extension = "/usr/local/Zend/lib/Guard-5.5.0/php-5.3.x/ZendGuardLoader.so"
extension = "eaccelerator.so"
extension = "pdo.so"
extension = "pdo_pgsql.so"
extension = "pdo_sqlite.so"
extension = "sqlite.so"
extension = "pdo_mysql.so"

Modified to work

; Directory in which the loadable extensions (modules) reside.
extension_dir = "/usr/local/lib/php/extensions/no-debug-non-zts-20090626"
extension_dir = "/usr/lib/php/extensions/no-debug-non-zts-20090626"
zend_extension = "/usr/local/IonCube/ioncube_loader_lin_5.3.so"
zend_extension = "/usr/local/Zend/lib/Guard-5.5.0/php-5.3.x/ZendGuardLoader.so"
extension = "eaccelerator.so"
extension = "pdo.so"
extension = "pdo_pgsql.so"
extension = "pdo_sqlite.so"
extension = "sqlite.so"
extension = "pdo_mysql.so"

1. Why did PECL install pdo-pgsql into the 2nd extension directory and not the first?

2. Is it recommended to have 2 extension_dir as shown in the 2nd code snippet above?

Solution

1. Because it is the default location when installing via pecl install, while if you compile PHP from source, the extension path should be /usr/local/lib/php/extensions/no-debug-non-zts-20090626.

2. As far as I know, PHP doesn't support multiple extension_dir, it only pick the last one. Just type php -i | grep eaccelerator to see what happens.

The workaround is copy the extensions to the right path.

Comments

[Juris Malinens]

or make symlinks...

[Nyxynyx]

Is this how I should make the symlinks? : ln -s /usr/lib/php/extensions/no-debug-non-zts-20090626 /usr/php/extensions/no-debug-non-zts-20090626

[Greg Petersen]

It should be: ln -s /usr/local/lib/php/extensions/no-debug-non-zts-20090626 /usr/lib/php/extensions/no-debug-non-zts-20090626. But rename it first: mv /usr/lib/php/extensions/no-debug-non-zts-20090626 /usr/lib/php/extensions/no-debug-non-zts-20090626.bak.

[Nyxynyx]

Why would you renname it first?

[Greg Petersen]

what happens if you link to a existing directory?