(This is despite the fact that during installation I explicitly specified that this MySQL server is going to be used for development, not for production.)
A quick search on the web shows that this preposterous amount of memory can be reduced to something less preposterous by editing my.ini (usually found in some place like ProgramData\MySQL\MySQL Server 5.6\) and replacing the following line:
table_definition_cache=1400
with this line:
table_definition_cache=400
Unfortunately, even though the savings are huge, the memory footprint of mysql is still nothing short of gargantuan:
