db2 database alias not listed via list database directory but still unable to create that database

I am trying to create a database by logging on to the linux server on which the db2 server is installed, as the instance owner

db2 => list database directory

 System Database Directory

 Number of entries in the directory = 1

Database 1 entry:

 Database alias                       = SAMPLE
 Database name                        = SAMPLE
 Local database directory             = /home/mylogin/sqllib
 Database release level               = f.00
 Comment                              =
 Directory entry type                 = Indirect
 Catalog database partition number    = 0
 Alternate server hostname            =
 Alternate server port number         =

db2 => create database testdb2
SQL1005N  The database alias "TESTDB2" already exists in either the local 
database directory or system database directory.
    db2 => list database directory on /home/mylogin/sqllib

 Local Database Directory on /home/mylogin/sqllib

 Number of entries in the directory = 1

Database 1 entry:

 Database alias                       = SAMPLE
 Database name                        = SAMPLE
 Database directory                   = SQL00001
 Database release level               = f.00
 Comment                              =
 Directory entry type                 = Home
 Catalog database partition number    = 0
 Database member number               = 0
db2 => quit

I also checked if there are any other instances that exist other than mine, but there aren't.

DB20000I  The QUIT command completed successfully.
-bash-4.1$ db2ilist
mylogin

While the alias testdb2 is not listed by list database directory , db2 claims that this alias already exists in either the system database directory or the local database directory.

If this is true, how do I get the equivalent of list database directory that lists testdb2 as well?

There is a database in the default database path which has the same name and not cataloged. You must first catalog it, then drop it. After that you can create a database with that name. If you can't do it or don't want to drop it, then use ON PATH and DBPATH parameters of the CREATE DB statement and provide a different directory than the default directory.

Here is a workaround for your problem:

db2 catalog database testdb2 as oldtestdb
db2 create database testdb2x
db2 uncatalog database testdb2x
db2 catalog database testdb2x as testdb2

Now you have your database testdb2

StackExchange Database Administrators Q#50020, answer score: 2