Instant Client FAQs

Instant Client's advantages are that installation is a quick unzip of a ZIP package, or the trivial install of Linux RPM packages. Instant Client's footprint is much, much smaller than the full Oracle Client. Other advantages are that it is available under an OTN license that allows redistribution. Your Instant Client-based applications can take full advantage of Oracle Client features such as caching and connection pooling; they can take advantage of Oracle Net features such as network encryption; and of course they can use big and small Oracle Database features.

Instant Client is free from OTN for anyone to use in a development or production environment. However, customers can only call Oracle Support if they already have a standard support contract.

Subject to the license, Instant Client can be bundled and redistributed for free. Enterprises can redistribute Instant Client within their organizations. However, customers can only call Oracle Support for Instant Client if they have a standard support contract.

As long as the library loading path has the directory containing Instant Client files (e.g. the instantclient directory) ahead of library directory in ORACLE_HOME, the application will operate in the Instant Client mode, and the libraries in the ORACLE_HOME will not be used.

Environment variables ORA_NLS33, ORA_NLS32, and ORA_NLS are ignored in the Instant Client mode. The ORA_TZFILE environment variable should be set to the name of the large timezone file as opposed to its full path. All other environment variables (such as NLS_LANG) have no change in behavior.

Some Oracle applications are currently certifying operation under Instant Client. Once certification is complete, the message will disappear.

The Instant Client libraries occupy a virtual address space that is equal to the size of the files. However, only frequently used error messages from the libraries occupy physical memory. Under most cases, the physical memory load is a few kilobytes despite the larger reserved virtual address space.

Special settings for Instant Client enabled applications can be set in the registry for all users or on a per-user basis. 1. Using a registry editor (regedit or regedt32), go to HKEY_LOCAL_MACHINE\SOFTWARE for a global setting (or HKEY_LOCAL_MACHINE\HKEY_CURRENT_USER\SOFTWARE for each specific user).2. Add ORACLE group key.3. Add a new string value within the ORACLE key for the different settings you are interested in (NLS_LANG, TNS_ADMIN, etc.). For keys that are directories, use a fully qualified path.

If you already have Oracle Client installed on your machine, then we recommend: 1. Do NOT unzip or copy the Instant Client libraries to either of ORACLE_HOME/lib or ORACLE_HOME/bin directories, to avoid overwriting files and leaving the installation in an inconsistent state. In general, we recommend putting the Instant Client libraries into a separate clean directory.2. Do NOT put both the Instant Client directory AND the Oracle Client directory in the Library Path, regardless of ordering. Please use either one or the other in the Library Path (LD_LIBRARY_PATH or PATH, depending on platform), but not both, based on the version you wish to use.

Files like "tnsnames.ora", "sqlnet.ora" and "oraaccess.xml" will be located by Instant Client by setting the TNS_ADMIN environment variable or registry entry to the directory containing the files. Use the full directory path; do not include a file name. Alternatively create a subdirectory "network/admin" under the Instant Client directory for the Oracle Net files. This is the default location and so no TNS_ADMIN variable is required.

Yes, LDAP can be used with Instant Client, as of 10.1.0.4.

Yes, Pro*C is supported to run with Instant Client 10.2.0.x and later versions on Unix platforms. Pro*C is supported with Instant Client 11.2.0.1 and later versions on Windows.