Are you running $system.OBJ.Load("name of file") without specifying any qualifiers? If so, I believe the default qualifiers are "CUK" (compile, update only, keep source). You might want to try $system.OBJ.Load("name of file", "CK") and see if that helps.

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KE…
You can just do "SELECT TOP X FROM ...." where X is the number of rows you're looking for. As mentioned in the above link

To resolve the issues with airlines.dat, do the following

Add to the JVM arguments of %Java Sever, "-Dfile.encoding=UTF-8" without the quotes

Edit airlines.dat and make the following changes

• Replace "\N" which is a MySQL specific token with "" (i.e. the empty string). Due to specific interactions with InterSystem's JDBC clients with IRIS, "" is interpreted as NULL when inserted as a string. 
• Replace "\\'" (the escaped apostrophe) with "'" (just the single apostrophe) as InterSystem's JDBC clients do not require the escape character (which would otherwise be required in SQL).

This will allow all 6162 rows be inserted.