The DB2INSTANCE environment is set
according to the DB2® copy that
your environment is currently set up to use. If you do not set it
explicitly to an instance in the current copy, it defaults to the
default instance that is specified with the DB2INSTDEF profile
registry variable.
About this task
DB2INSTDEF is the default instance variable
that is specific to the current DB2 copy
in use. Every DB2 copy has its
own
DB2INSTDEF profile registry variable. Instance
names must be unique on the system; when an instance is created, the
database manager scans through existing copies to ensure its uniqueness.
Use
the following guidelines to set the default instance when using multiple DB2 copies:
- If DB2INSTANCE is not set for a particular DB2 copy, then the value of DB2INSTDEF is
used for that DB2 copy. This
means:
- If DB2INSTANCE=ABC and DB2INSTDEF=XYZ, ABC is
the value that is used
- If DB2INSTANCE is not set and DB2INSTDEF=XYZ, XYZ is
used
- If DB2INSTANCE is not set and DB2INSTDEF is
not set, then any application or command that depends on a valid DB2INSTANCE will
not work.
- You can use either the db2envar.bat command
or the db2SelectDB2Copy API to switch DB2 copies. Setting all the environment variables
appropriately (for example, PATH, INCLUDE, LIB,
and DB2INSTANCE) will also work, but you must
ensure that they are set properly.
Note: Using the
db2envar.bat command
is not quite the same as setting the environment variables. The
db2envar.bat command
determines which DB2 copy it
belongs to, and then adds the path of this DB2 copy to the front of the
PATH environment
variable.
When there are multiple DB2 copies
on the same computer, the PATH environment variable
can point to only one of them: the DEFAULT COPY. For example, if DB2COPY1
is under c:\sqllib\bin and is the default copy;
and DB2COPY2 is under d:\sqllib\bin. If you want
to use DB2COPY2 in a regular command window, you would run d:\sqllib\bin\db2envar.bat in
that command window. This adjusts the PATH (and
some other environment variables) for this command window so that
it picks up binaries from d:\sqllib\bin.
- DB2INSTANCE is only valid for instances under
the DB2 copy that you are using.
However, if you switch copies by running the db2envar.bat command, DB2INSTANCE is updated
to the value of DB2INSTDEF for the DB2 copy that you switched to initially.
- DB2INSTANCE is the current DB2 instance that is used by applications that
are executing in that DB2 copy.
When you switch between copies, by default, DB2INSTANCE is
changed to the value of DB2INSTDEF for that copy. DB2INSTDEF is
less meaningful on a one copy system because all the instances are
in the current copy; however, it is still applicable as being the
default instance, if another instance is not set.
- All global profile registry variables are specific to a DB2 copy, unless you specify them
using SET VARIABLE=variable_name.
DB2 10.5 for Linux, UNIX, and Windows