The code was a legacy from the first versions of the XDB engine dating 2004
  and was not working anymore with recent versions of MySQL/MariaDB. A patch
  in create had been added but is was unsatisfying, recreating all indexes on
  any alter statement and sometimes doing nothing when it should have.
  This is a major update to be tested for stability. It was in most important
  cases et all current tests pass with this new version

modified:
  storage/connect/global.h
  storage/connect/ha_connect.cc
  storage/connect/ha_connect.h
  storage/connect/mycat.cc
  storage/connect/plugutil.c
  storage/connect/tabdos.cpp
  storage/connect/user_connect.cc
  storage/connect/user_connect.h
  storage/connect/xindex.h