I issued the command:
codeql database create ./databases/Pixi --language="javascript" --source-root="Pixi"
And got the following errors:
Initializing database at /sda8/codeql-2.11.1/program/databases/Pixi. A fatal error occurred: There's no CodeQL extractor named 'javascript' installed.
codeql version is 2.11.1.
The reason for the error "no CodeQL extractor" found is because "codeql" as found in the $PATH was symbolically linked to the actual codeql.
For example, actual codeql was located at /sda8/codeql-2.11.1/codeql, but:
PATH=$HOME/codeql:$PATH
and
$HOME/codeql -> /sda8/codeql-2.11.1/codeql
the codeql as accessed in the $PATH was $HOME/codeql, symbolically linked to /sda8/codeql-2.11.1/codeql.
This will consistently give rise to the same error - over many different version of CodeQL.