Review the previous Requirements section before configuring OCI8.
Before starting the web server, OCI8 typically requires several Oracle environment variables (see below) to locate libraries, point to configuration files, and set some basic properties such as the character set used by Oracle libraries. The variables must be set before any PHP process starts.
The PHP binary must link with the same, or more recent, major version of Oracle libraries as it was configured with. For example, if you build OCI8 with Oracle 19 libraries, then PHP should also be deployed and run with Oracle 19 libraries. PHP applications can connect to other versions of Oracle Database, since Oracle has client-server cross-version compatibility.
The OCI8 extension can be added to an existing PHP installation by using the » PECL repository.
If you are behind a firewall, set PEAR's proxy, for example:
pear config-set http_proxy http://my-proxy.example.com:80/
Run
pecl install oci8
     For PHP 7, use pecl install oci8-2.2.0
    
     When prompted, enter either the value of $ORACLE_HOME, or
     instantclient,/path/to/instant/client/lib.
    
      Note: Do not enter variable names like $ORACLE_HOME
      or $HOME because pecl will not
      expand them.  Instead, enter an expanded path, for
      example /opt/oracle/product/19c/dbhome_1
      or instantclient,/Users/myname/Downloads/instantclient_19_8
    
     If you get an error oci8_dtrace_gen.h: No such file or
     directory, it means PHP was built
     with DTrace Dynamic Tracing enabled.
     Install using:
    
$ export PHP_DTRACE=yes $ pecl install oci8
Edit your php.ini file and add the line:
extension=oci8.so
Make sure the php.ini directive extension_dir is set to the directory that oci8.so was installed in.
  To install OCI8 on an existing PHP installation when
  the pecl command is not available, manually download
  the » PECL OCI8 package,
  e.g. oci8-3.0.0.tgz.
 
Extract the package:
tar -zxf oci8-3.0.0.tgz cd oci8-3.0.0
Prepare the package:
phpize
     Configure the package, either
     using $ORACLE_HOME or Instant Client
    
./configure -with-oci8=shared,$ORACLE_HOME
or
./configure -with-oci8=shared,instantclient,/path/to/instant/client/lib
Install the package:
make install
     If you get an error oci8_dtrace_gen.h: No such file or
     directory, it means PHP was built
     with DTrace Dynamic Tracing enabled.
     Re-run the configure and make
     commands after setting this environment variable:
    
$ export PHP_DTRACE=yes
Edit your php.ini file and add the line:
extension=oci8.so
Make sure the php.ini directive extension_dir is set to the directory that oci8.so was installed in.
  If you are building PHP from source code, the
  configuration shared option can be used to build OCI8 as a shared library
  that can be dynamically loaded into PHP.  Building a shared extension allows
  OCI8 to be upgraded easily without impacting the rest of PHP.
 
Configure OCI8 using one of the following configure options.
If using the free » Oracle Instant Client libraries, then do:
./configure --with-oci8=shared,instantclient,/path/to/instant/client/lib
     If Instant Client 12.2 (or earlier) is installed from ZIP files, make sure to create
     the library symbolic link first, for example ln -s
     libclntsh.so.12.1 libclntsh.so.
    
If using an RPM-based installation of Oracle Instant Client, the configure line will look like this:
./configure --with-oci8=shared,instantclient,/usr/lib/oracle/<version>/client/lib
For example, --with-oci8=shared,instantclient,/usr/lib/oracle/19.9/client/lib
Note that Oracle Instant Client support first appeared in PHP 4.3.11 and 5.0.4 and originally used the option --with-oci8-instant-client to configure PHP.
If using an Oracle database or full Oracle Client installation then do:
./configure --with-oci8=shared,$ORACLE_HOME
     Make sure the web server user
     (nobody, www) has access to
     the libraries, initialization files
     and tnsnames.ora (if used) under
     the $ORACLE_HOME directory.  With Oracle
     10gR2, you may need to run
     the $ORACLE_HOME/install/changePerm.sh
     utility to give directory access.
    
After configuration, follow the usual PHP building procedure, e.g. make install. The OCI8 shared extension oci8.so library will be created. It may need to be manually moved to the PHP extension directory, specified by the extension_dir option in your php.ini file.
To complete installation of OCI8, edit php.ini and add the line:
extension=oci8.so
If you are building PHP from source code, you can configure PHP to include OCI8 as a static extension using one of the following configure options.
If using Oracle Instant Client, then do:
./configure --with-oci8=instantclient,/path/to/instant/client/lib
If using an Oracle database or full Oracle Client installation then do:
./configure --with-oci8=$ORACLE_HOME
After configuration, follow the usual PHP building procedure, e.g. make install. After successful compilation, you do not need to add oci8.so to php.ini. No additional build steps are required.
  The OCI8 extension can be added to an existing PHP installation by using the
  DLLs from » PECL repository or
  the libraries in your PHP installation's ext directory.
 
  With Oracle 12c (or later) libraries, uncomment one of
  the php.ini lines extension=php_oci8_12c.dll
  or extension=php_oci8_11g.dll
  or extension=php_oci8.dll. Only one of these DLLs may be
  enabled at a time. DLLs with higher versions may contain more
  functionality. Not all DLLs may be available for all versions of PHP.  Make
  sure extension_dir is set to the
  directory containing the PHP extension DLLs.
 
If using Instant Client, set the system PATH environment variable to the Oracle library directory.
Before using this extension, make sure that the Oracle environment variables are properly set for the web daemon user. If your web server is automatically started at boot time then make sure that the boot-time environment is also configured correctly.
Note:
Do not set Oracle environment variables using putenv() in a PHP script because Oracle libraries may be loaded and initialized before your script runs. Variables set with putenv() may then cause conflicts, crashes, or unpredictable behavior. Some functions may work but others might give subtle errors. The variables should be set up before the web server is started.
  On Red Hat Linux and variants, export variables at the end of
  /etc/sysconfig/httpd.  Other systems with
  Apache 2 may use an envvars script in the
  Apache bin directory.  A third option, the
  Apache SetEnv directive
  in httpd.conf, may work in some systems but is
  known to be insufficient in others.
 
To check that environment variables are set correctly, use phpinfo() and check the Environment (not the Apache Environment) section contains the expected variables.
The variables that might be needed are included in the following table. Refer to the Oracle documentation for more information on all the available variables.
| Name | Purpose | 
|---|---|
| ORACLE_HOME | Contains the directory of the full Oracle Database software. Do not set this when using Oracle Instant Client as it is unnecessary and may cause installation problems. | 
| ORACLE_SID | Contains the name of the database on the local machine to be connected to. There is no need to set this if you using Oracle Instant Client, or always pass the connection parameter to oci_connect(). | 
| LD_LIBRARY_PATH | Set this (or its platform equivalent, such
      as LIBPATH, orSHLIB_PATH) to the
      location of the Oracle libraries, for
      example $ORACLE_HOME/lib
      or /usr/lib/oracle/18.5/client/lib. Note with Instant
      Client ZIP files on Linux it is more reliable to
      use ldconfig instead, see the Instant Client
      installation instructions.  With Instant Client 19 (or later) RPM
      files,ldconfigis automatically run for you.  Some
      users useLD_PRELOADinstead
      ofLD_LIBRARY_PATH. | 
| NLS_LANG | This is the primary variable for setting the character set and globalization information used by the Oracle libraries. | 
| ORA_SDTZ | Sets the Oracle session timezone. | 
| TNS_ADMIN | Contains the directory where the Oracle Net Services configuration
      files such as tnsnames.ora
      and sqlnet.ora are kept.  Not needed if
      the oci_connect() connection string uses the Easy
      Connect naming syntax such as localhost/XE.  Not needed
      if the network configuration files are in one of the default locations
      such
      as /usr/lib/oracle/VERSION/client/lib/network/admin, $ORACLE_HOME/network/admin
      or /etc. | 
TWO_TASK, ORA_TZFILE, and the
   various Oracle globalization settings
   like NLS* and the ORA_NLS_*
   variables.  
 
The most common problem with installing OCI8 is not having the Oracle environment correctly set. This typically appears as a problem using oci_connect() or oci_pconnect(). The error may be a PHP error such as Call to undefined function oci_connect(), an Oracle error such as ORA-12705, or even an Apache crash. Check the Apache log files for startup errors and see the sections above to resolve this problem.
While network errors like ORA-12154 or ORA-12514 indicate an Oracle network naming or configuration issue, the root cause may be because the PHP environment is incorrectly set up and Oracle libraries are unable to locate the tnsnames.ora configuration file.
On Windows, having multiple versions of Oracle on the one machine can easily cause library clashes unless care is taken to make sure PHP only uses the correct version of Oracle.
A utility to examine what libraries are being looked for and loaded can help resolve missing or clashing library issues, particularly on Windows.
Note: If the web server doesn't start or crashes at startup
Check that Apache is linked with the pthread library:
# ldd /www/apache/bin/httpd libpthread.so.0 => /lib/libpthread.so.0 (0x4001c000) libm.so.6 => /lib/libm.so.6 (0x4002f000) libcrypt.so.1 => /lib/libcrypt.so.1 (0x4004c000) libdl.so.2 => /lib/libdl.so.2 (0x4007a000) libc.so.6 => /lib/libc.so.6 (0x4007e000) /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)If the libpthread is not listed, then reinstall Apache:
# cd /usr/src/apache_1.3.xx # make clean # LIBS=-lpthread ./config.status # make # make installPlease note that on some systems like UnixWare, it is libthread instead of libpthread. PHP and Apache have to be configured with EXTRA_LIBS=-lthread.