About varlena2

To reduce size of varlen2.vl_len to int16. This has been mentioned before,
but is there any show-stopper reasoning preventing us from doing that or
somebody has been working on it?

Sorry, just to repeat myself. Char types will benefit from that. Many
applications are from DB2, Oracle or SQL Server:
       Max Char Length
DB2         32672
SQL         8000
Oracle      4000

All of above just need varlena2. To support bigger char types, we could
follow the tradition "long varchar", etc. Or, we can introduce several new
data types like "short varchar" to keep compatible with previous
PostgreSQL applications.

Regards,
Qingqing