Oracle Instant Client and Oracle Instant Client Light

About Oracle Instant Client

Oracle Instant Client provides the necessary Oracle Database client-side files to create and run OCI, OCCI, ODBC, and JDBC OCI applications. Useful command-line utilities including SQL*Plus, SQL*Loader and Oracle Data Pump are also available. Oracle Instant Client simplifies the deployment of applications by eliminating the need for an Oracle home on the client machines.

The storage space requirement of an OCI application running in Instant Client mode is significantly reduced compared to the same application running in a full client-side installation. A minimal install of Instant Client shared libraries can occupy less than 10% of the space of a full client-side installation. Finally, the Instant Client is easy to install.

Why use Instant Client?

Installation involves unzipping a few files, or installing RPM packages.
The number of required files and the total disk storage are significantly reduced.
There is no loss of functionality or performance for applications deployed using Instant Client.
It is simple for independent software vendors to package applications.

A README file is included with the Instant Client installation. It describes the version, date and time, and the operating system the Instant Client was generated on.

OCI applications, by default, look for the OCI Data Shared Library, libociei.so (or Oraociei19.dll on Windows) in the runtime library search path (for example LD_LIBRARY_PATH on Linux, or PATH on Windows) to determine if the application should operate in the Instant Client mode. If this library is not found, then OCI tries to load the Instant Client Light Data Shared Library (see Table 2-3 and Table 2-4), libociicus.so (or Oraociicus19.dll on Windows). If the Instant Client Light library is found, then the application operates in the Instant Client Light mode. Otherwise, a full installation based on Oracle home is assumed.

For Instant Client, the following tables shows the Oracle Database client-side files required to deploy an OCI application for Linux and UNIX and Microsoft Windows. Other libraries and utilities get installed, but are not needed for OCI runtime use. For example, you can delete files such as jdbc.jar.

Table 2-1 Instant Client Shared Libraries for Linux and UNIX

Linux and UNIX	Description for Linux and UNIX
`libclntsh.so.19.1` `libclntshcore.so.19.1`	Client Code Library
`libociei.so`^Foot 1	OCI Instant Client Data Shared Library
`libnnz19.so`	Security Library
`libons.so`	Oracle Notification Service (ONS) library
`libmql1.so`	Light Weight IPC Library
`libipc1.so`	Message Queue Light Library

^Footnote 1

The libraries must reside in the same directory in order to use Instant Client.

Table 2-2 Instant Client Shared Libraries for Microsoft Windows

Microsoft Windows	Description for Microsoft Windows
`oci.dll`	Forwarding functions that applications link with
`oraociei19.dll`	Data and code
`orannzsbb19.dll`	Security Library
`oraons.dll`	ONS library used by OCI internally
`oci.sym` `oraociei19.sym` `orannzsbb19.sym`	Symbol tables

On Microsoft Windows, a .sym file is provided for each dynamic-link library (DLL). When the .sym file is present in the same location as the DLL, a stack trace with function names is generated when a failure occurs in OCI on Microsoft Windows.

In general, all OCI functionality is available to an application being run using the Instant Client, except that the Instant Client is for client-side operation only. Therefore, server-side external procedures cannot use Instant Client libraries.

For development you can also use the Instant Client SDK.

See Also:

Install from ZIP Files, from RPMs, and from Oracle Universal Installer

Oracle Instant Client can be installed in several ways.

The Instant Client libraries can be installed by either choosing the Instant Client option from Oracle Universal Installer or by downloading and installing either the ZIP files or RPMs from the OCI page on the Oracle Technology Network website: Oracle Instant Client.

The following sections describe different ways to download and Install the Instant Client Libraries from the Oracle Technology Network Website:

Installing from the ZIP files Installing from the RPM files Installing from the Oracle Universal Installer

Installing from the ZIP files

This section describes how to install the Instant Client from the ZIP files.

Download the desired Instant Client ZIP files. All installations require a Basic or Basic Light package.
Run the following command to unzip the packages into a single directory such as /opt/oracle/instantclient_19_3 that is accessible to your application:
```
cd /opt/oracle			
  unzip instantclient-basic-linux.x64-19.3.0.0.0dbru.zip
```
Run the following command for versions prior to 18.3 to create the appropriate links for the version of Instant Client:
```
cd /opt/oracle/instantclient_12_2
  ln -s libclntsh.so.12.1 libclntsh.so
  ln -s libocci.so.12.1 libocci.so
```
Install the libaio package. This is called libaio1 on some Linux distributions.
For example, on Oracle Linux, run the following command:
```
sudo yum install libaio
```
If Instant Client is the only Oracle software installed on this system then run the following command to update the runtime link path:
```
sudo sh -c "echo /opt/oracle/instantclient_19_3 >/etc/ld.so.conf.d/oracle-instantclient.conf"
  sudo ldconfig
```
Alternatively, run the following command to set the LD_LIBRARY_PATH environment variable prior to running the applications:
```
export LD_LIBRARY_PATH=/opt/oracle/instantclient_19_3:$LD_LIBRARY_PATH
```
The variable can be added optionally to the configuration files such as ~/.bash_profile and to the application configuration files such as /etc/sysconfig/httpd.
If you intend to co-locate the optional Oracle configuration files such as tnsnames.ora, sqlnet.ora, ldap.ora, or oraaccess.xml with Instant Client, then place them in the network/admin subdirectory. This needs to be created for 12.2 and earlier versions using the following command:
```
mkdir -p /opt/oracle/instantclient_12_2/network/admin
```
This is the default Oracle configuration directory for applications linked with the Instant Client.

Alternatively, Oracle configuration files can be placed in another accessible directory and then set the environment variable TNS_ADMIN to that directory name.
To use binaries such as sqlplus from the SQL*Plus package, unzip the package to the same directory as the Basic package and then update the PATH environment variable as follows:
```
export PATH=/opt/oracle/instantclient_19_3:$PATH
```
Start your application.

Installing from the RPM files

This section describes how to install the Instant Client from the RPM files.

Download the desired Instant Client RPM files. All installations require a Basic or Basic Light package.
Run the following command to install the packages with yum:
```
sudo yum install oracle-instantclient19.3-basic-19.3.0.0.0-1.x86_64.rpm
```
Note:

Starting from version 19.3, by default only one version of the Instant Client RPM libraries can be installed at a time.
For versions prior to 19, if Instant Client is the only Oracle software installed on the system, then run the following command to update the runtime link path:
```
sudo sh -c "echo /usr/lib/oracle/18.3/client64/lib >/etc/ld.so.conf.d/oracle-instantclient.conf"
  sudo ldconfig
```
Note:

For Instant Client 19.3 RPM packages, these commands are run automatically.

Alternatively, run the following command to set the LD_LIBRARY_PATH environment variable prior to running the applications:
```
export LD_LIBRARY_PATH=/opt/oracle/instantclient_19_3:$LD_LIBRARY_PATH
```
The variable can optionally be added to configuration files such as ~/.bash_profile and to the application configuration files such as /etc/sysconfig/httpd.
If you intend to co-locate the optional Oracle configuration files such as tnsnames.ora, sqlnet.ora, ldap.ora, or oraaccess.xml with Instant Client, then place them in the network/admin subdirectory. This needs to be created for 12.2 and earlier versions using the following command:
```
sudo mkdir -p /usr/lib/oracle/12.2/client64/lib/network/admin
```
This is the default Oracle configuration directory for applications linked with the Instant Client.

Alternatively, Oracle configuration files can be placed in another accessible directory and then set the environment variable TNS_ADMIN to that directory name.
To use binaries tools package, use yum to install the package to the same directory as the Basic package and then update the PATH environment variable as follows:
```
export PATH=/opt/oracle/instantclient_19_3:$PATH
```
Start your application.

Installing from the Oracle Universal Installer

This section describes how to install Oracle Instant Client from the Oracle Universal Installer.

For installing Instant Client from Oracle Universal Installer, invoke the Oracle Universal Installer, select the Instant Client option and then install the Instant Client shared libraries to an empty directory, such as instantclient_19_3, for Oracle Database release 19c, version 19.3.

See Steps 5 and 6 in Installing from the ZIP files about setting the environment variables.

If you did a complete client installation (by choosing the Admin option in Oracle Universal Installer), the locations of the Instant Client shared libraries in a full client installation are:

On Linux or UNIX:

libociei.so library is in $ORACLE_HOME/instantclient

libclntsh.so.19.1, libclntshcore.so.19.1, and libnnz19.so are in $ORACLE_HOME/lib

On Windows:

oraociei19.dll library is in ORACLE_HOME\instantclient

oci.dll, ociw32.dll, and orannzsbb19.dll are in ORACLE_HOME\bin

To enable running the OCI application using Instant Client, copy the preceding libraries to a different directory and then set the operating system shared library path to locate this directory.

Note:

All the libraries must be copied from the same Oracle home and must be placed in the same directory. Co-location of symlinks to Instant Client libraries is not a substitute for physical co-location of the libraries.

There should be only one set of Oracle libraries on the operating system Library Path variable. That is, if you have multiple directories containing Instant Client libraries, then only one such directory should be on the operating system Library Path.

Similarly, if an Oracle home-based installation is performed on the same system, then you should not have ORACLE_HOME/lib and the Instant Client directory on the operating system Library Path simultaneously regardless of the order in which they appear on the Library Path. That is, either the ORACLE_HOME/lib directory (for non-Instant Client operation) or Instant Client directory (for Instant Client operation) should be on the operating system Library Path variable, but not both.

To enable other capabilities such as OCCI and JDBC OCI, you must copy a few additional files. To enable OCCI, you must install the OCCI Library (libocci.so.19.1 on Linux or UNIX and oraocci19.dll on Windows) in the Instant Client directory. For the JDBC OCI driver, in addition to the three OCI shared libraries, you must also download OCI JDBC Library (for example libocijdbc19.so on Linux or UNIX and ocijdbc19.dll on Windows). Place all libraries in the Instant Client directory.

Note:

On hybrid platforms, such as Sparc64, to operate the JDBC OCI driver in the Instant Client mode, copy the libociei.so library from the ORACLE_HOME/instantclient32 directory to the Instant Client directory. Copy all other Sparc64 libraries needed for the JDBC OCI Instant Client from the ORACLE_HOME/lib32 directory to the Instant Client directory.

Environment Variables for Oracle Instant Client

The ORACLE_HOME environment variable no longer determines the location of NLS, CORE, and error message files.

An OCI-only application should not require ORACLE_HOME to be set. However, if it is set, it does not affect OCI. OCI always obtains its data from the Data Shared Library. If the Data Shared Library is not available, only then is ORACLE_HOME used and a full client installation is assumed. Though ORACLE_HOME is not required to be set, if it is set, then it must be set to a valid operating system path name that identifies a directory.

If Dynamic User callback libraries are to be loaded, then as this guide specifies, the callback package must reside in ORACLE_HOME/lib (ORACLE_HOME\bin on Windows). Set ORACLE_HOME in this case.

Environment variables ORA_NLS10 and ORA_NLS_PROFILE33 are ignored in the Instant Client mode.

Beginning with Oracle Database 12c Release 2 (12.2), when using Instant Client libraries, the Instant Client can use the ORA_TZFILE environment variable to read the time zone file from the file system when this environment variable is set. Otherwise, if the ORA_TZFILE variable is not set, then the larger, default, timezlrg_n.dat file from the Data Shared Library is used. If the smaller timezone_n.dat file is to be used from the Data Shared Library, then set the ORA_TZFILE environment variable to the name of the file without any absolute or relative path names. The file must be copied to subdirectory oracore/zoneinfo for (UNIX/LINUX) or oracore\zoneinfo for (Microsoft Windows) in the instant client directory. You can use the genezi utility with the -v option to verify that the time zone file and location is valid or run SQL*Plus.

On Linux or UNIX:

export ORA_TZFILE=timezone_n.dat

On Windows:

set ORA_TZFILE=timezone_n.dat

In these examples, n is the time zone data file version number.

Be sure to create subdirectory oracore/zoneinfo for (UNIX/LINUX) or subdirectory oracore\zoneinfo for (Microsoft Windows) where oracoei or oraociicus DLL's are located (typically in the instantclient_12_2 directory) and copy the timezone_n.dat file to this directory.

To determine the versions of small and large time zone files that are packaged in the Instant Client Data Shared Library, enter the following command to run the genezi utility:

genezi -v

If OCI is not operating in the Instant Client mode (because the Data Shared Library is not available), then ORA_TZFILE variable, if set, names a complete path name as it does in previous Oracle Database releases.

If TNSNAMES local naming parameters are used, then, as mentioned earlier, TNS_ADMIN directory must contain the TNSNAMES configuration files. If TNS_ADMIN is not set, then the ORACLE_HOME/network/admin directory must contain Oracle Net Services configuration files.

Database Connection Strings for Oracle Instant Client

All Oracle Net naming methods that do not require use of ORACLE_BASE_HOME, or ORACLE_HOME (to locate configuration files such as tnsnames.ora, sqlnet.ora, or oraaccess.xml) work with the Instant Client mode.

You can use the network/admin to co-locate optional Oracle configuration files such as tnsnames.ora, sqlnet.ora, ldap.ora, or oraaccess.xml with Instant Client. Prior to release 18.1, the users had to create the network/admin directory manually.

See Database Connection Strings for complete information about database connection strings.

See Also:

Oracle Database Net Services Administrator's Guide chapter on "Configuring Naming Methods" for more about connect descriptors

This section includes the following topic: Examples of Oracle Database Connection String Connect Identifiers.

SDK for Oracle Instant Client

The software development kit (SDK) is a set of development tools that allows the creation of applications can be downloaded from the Instant Client link URL on the Oracle Technology Network website:

Oracle Instant Client

The Instant Client SDK package has both C and C++ header files and a makefile for developing OCI and OCCI applications while in an Instant Client environment. Developed applications can be deployed in any client environment.
The SDK contains C and C++ demonstration programs.
On Windows, libraries required to link the OCI or OCCI applications are also included. Make.bat is provided to build the demos.
On UNIX or Linux, the makefile demo.mk is provided to build the demos. The instantclient_19 directory must be in the runtime library search path, for example LD_LIBRARY_PATH before linking the application. The OCI and OCCI programs require the presence of libclntsh.so and libocci.so symbolic links in the instantclient_19 directory. Beginning with Oracle Database 18c, version 18.1, Instant Client Basic and Basic Light ZIP files on Linux, Unix, and macOS now have the libclntsh and libocci symbolic links precreated.
The SDK also contains the Object Type Translator (OTT) utility and its classes to generate the application header files.

About Oracle Instant Client Light

The Instant Client Light version of Instant Client further reduces the disk space requirements of the client installation.

The size of the library has been reduced by removing error message files for languages other than English and leaving only a few supported character set definitions out of around 250.

This Instant Client Light version is geared toward applications that use either US7ASCII, WE8DEC, WE8ISO8859P1, WE8MSWIN1252, or a Unicode character set. There is no restriction on the LANGUAGE and the TERRITORY fields of the NLS_LANG setting, so the Instant Client Light operates with any language and territory settings. Because only English error messages are provided with the Instant Client Light, error messages generated on the client side, such as Net connection errors, are always reported in English, even if NLS_LANG is set to a language other than AMERICAN. Error messages generated by the database side, such as syntax errors in SQL statements, are in the selected language provided the appropriate translated message files are installed in the Oracle home of the database instance.

This section includes the following topics:

Globalization Settings

Instant Client Light supports the following client character sets:

Single-byte

US7ASCII
WE8DEC
WE8MSWIN1252
WE8ISO8859P1

Unicode

UTF8
AL16UTF16
AL32UTF8

Instant Client Light can connect to databases having one of these database character sets:

US7ASCII
WE8DEC
WE8MSWIN1252
WE8ISO8859P1
WE8EBCDIC37C
WE8EBCDIC1047
UTF8
AL32UTF8

Instant Client Light returns an error if a character set other than those in the preceding lists is used as the client or database character set.

Instant Client Light can also operate with the OCI Environment handles created in the OCI_UTF16 mode.

See Also:

Oracle Database Globalization Support Guide for more information about National Language Support (NLS) settings

Libraries for Oracle Instant Client Light

OCI applications, by default, look for the OCI Data Shared Library, libociei.so (or Oraociei119.dll on Windows) in the runtime library search path (for example LD_LIBRARY_PATH on Linux, or PATH on Windows) to determine if the application should operate in the Instant Client mode.

If the OCI Data Shared Library is not found, then OCI tries to load the Instant Client Light Data Shared Library (see Table 2-3 and Table 2-4), libociicus.so (or Oraociicus19.dll on Windows). If the Instant Client Light library is found, then the application operates in the Instant Client Light mode. Otherwise, a full installation based on Oracle home is assumed.

Table 2-3 Instant Client Light Shared Libraries Linux and UNIX

Linux and UNIX	Description for Linux and UNIX
`libclntsh.so.19` `libclntshcore.so.19`	Client Code Library
`libociicus.so`	OCI Instant Client Light Data Shared Library
`libnnz19.so`	Security Library
`libons.so`	Oracle Notification Service (ONS) library
`libmql1.so`	Light Weight IPC Library
`libipc1.so`	Message Queue Light Library

Table 2-4 Instant Client Light Shared Libraries for Microsoft Windows

Microsoft Windows	Description for Microsoft Windows
`oci.dll`	Forwarding functions that applications link with
`oraociicus19.dll`	Data and code
`orannzsbb19.dll`	Security Library
`oci.sym` `oraociicus19.sym` `orannzsbb19.sym`	Symbol tables

See Also:

Instant Client Shared Libraries for Linux and UNIX Table 2-1

Instant Client Shared Libraries for Microsoft Windows Table 2-2

Installing Oracle Instant Client Light

How can Instant Client Light can be installed.

Instant Client Light can be installed in one of these ways:

Installed from Oracle Technology Network (OTN)

The following URL is the Instant Client page on the Oracle Technology Network website: Oracle Instant Client

For Instant Client Light, download and unzip the basiclite.zip package in to an empty instantclient_12_2 directory.
Installed from an Instant Client Administrator installation

From the ORACLE_HOME/instantclient/light subdirectory, copy libociicus.so (or oraociicus12.dll on Windows). The Instant Client directory on the LD_LIBRARY_PATH (PATH on Windows) should contain the Instant Client Light Data Shared Library, libociicus.so (oraociicus12.dll on Windows), instead of the larger OCI Instant Client Data Shared Library, libociei.so (oraociei12.dll on Windows).
Installed from an Oracle Universal Installer installation

When you select the Instant Client option from the Oracle Universal Installer, libociei.so (or oraociei12.dll on Windows) is installed in the base directory of the installation, which means these files are placed on the LD_LIBRARY_PATH (PATH on Windows).

The Instant Light Client Data Shared Library, libociicus.so (or oraociicus12.dll on Windows), is installed in the light subdirectory of the base directory and not enabled by default. Therefore, to operate in the Instant Client Light mode, the OCI Data Shared Library, libociei.so (or Oraociei12.dll on Windows) must be deleted or renamed and the Instant Client Light library must be copied from the light subdirectory to the base directory of the installation.

For example, if Oracle Universal Installer has installed the Instant Client in my_oraic_12_2 directory on the LD_LIBRARY_PATH (PATH on Windows), then use the following command sequence to operate in the Instant Client Light mode:
```
cd my_oraic_12_2
rm libociei.so
mv light/libociicus.so .
```
Note:

To ensure that no incompatible binaries exist in the installation, always copy and install the Instant Client files in to an empty directory.

About Patching Oracle Instant Client Shared Libraries on Linux or UNIX

Because Instant Client is a deployment feature, the number and size of files (client footprint) required to run an OCI application has been reduced.

Hence, all files needed to patch Instant Client shared libraries are not available in an Instant Client deployment. A complete client installation based on Oracle home is needed for patching. Use the opatch utility for patching.

After you apply the patch in an Oracle home environment, copy the files listed in About Oracle Instant Client to the instant client directory, as described in Install from ZIP Files, from RPMs, and from Oracle Universal Installer.

Instead of copying individual files, you can generate Instant Client zip and RPM files for OCI and OCCI, JDBC, and SQL*Plus as described in Regeneration of Data Shared Library and Zip and RPM Files. Then, you can copy the zip and RPM files to the target system and unzip them as described in Install from ZIP Files, from RPMs, and from Oracle Universal Installer.

The opatch utility stores the patching information of the ORACLE_HOME installation in libclntsh.so. This information can be retrieved by the following command:

genezi -v

If the Instant Client deployment system does not have the genezi utility, you can copy it from the ORACLE_HOME/bin directory.

Note:

The opatch utility is not available on Windows.

Regeneration of Data Shared Library and Zip and RPM Files

The process to regenerate the data shared library and the zip and RPM files changed in Oracle Database 12c Release 1 (12.1).

Separate make file targets are used to create the data shared libraries, zip, and RPM files either individually or all at once. Currently, ilibociei builds only the zip and RPM files. Regeneration of data shared libraries requires both a compiler and linker, which may not be available on all installations. The sections that follow show the make file target used to regenerate data shared libraries, zip, and RPM files.

Note:

The regenerated Instant Client binaries contain only the Instant Client files installed in the Oracle Client Administrator Home from which the regeneration is done. Therefore, error messages, character set encodings, and time zone files that are present in the regeneration environment are the only ones that are packaged in the data shared libraries. Error messages, character set encodings, and time zone files depend on which national languages were selected for the installation of the Oracle Client Administrator Home.

Regeneration of the data shared library and the zip and RPM files is not available on Windows platforms.

This section includes the following topics:

Regenerating Data Shared Library libociei.so

The OCI Instant Client Data Shared Library (libociei.so) can be regenerated by using the following commands in an Administrator Install of ORACLE_HOME:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociei

The new regenerated libociei.so is placed in the ORACLE_HOME/instantclient directory. The original existing libociei.so located in this same directory is renamed to libociei.so0.

Regenerating Data Shared Library libociicus.so

To regenerate Instant Client Light data shared library (libociicus.so), use the following commands:

mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenlibociicus

The newly regenerated libociicus.so is placed in the ORACLE_HOME/instantclient/light directory. The original existing libociicus.so located in this same directory is renamed to libociicus.so0.

Regenerating Data Shared Libraries libociei.so and libociicus.so in One Step

To regenerate the data shared libraries libociei.so and libociicus.so, use the following commands:

mkdir -p $ORACLE_HOME/rdbms/install/instantclient/light
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk igenliboci

The newly regenerated libociei.so is placed in the ORACLE_HOME/instantclient directory. The original existing libociei.so located in this same directory is renamed to libociei.so0.

The newly regenerated libociicus.so is placed in the ORACLE_HOME/instantclient/light directory. The original existing libociicus.so located in this same directory is renamed to libociicus.so0.

Regenerating Zip and RPM Files for the Basic Package

To regenerate the zip and RPM files for the basic package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basic_zip

Regenerating Zip and RPM Files for the Basic Light Package

To regenerate the zip and RPM files for the basic light package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_basiclite_zip

Regenerating Zip and RPM Files for the JDBC Package

To regenerate the zip and RPM files for the JDBC package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_jdbc_zip

Regenerating Zip and RPM Files for the ODBC Package

To regenerate the zip and RPM files for the ODBC package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_odbc_zip

Regenerating Zip and RPM Files for the SQL*Plus Package

To regenerate the zip and RPM files for the SQL*Plus package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_sqlplus_zip

Regenerating Zip and RPM Files for the Tools Package

To regenerate the zip and RPM files for the tools package, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ic_tools_zip

Regenerating Zip and RPM Files for All Packages

To regenerate the zip and RPM files for all packages, use the following commands:

cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk ilibociei

The new zip and RPM files are generated under the following directory:

$ORACLE_HOME/rdbms/install/instantclient

Regeneration of the data shared library and the zip and RPM files is not available on Windows platforms.