Mysql config for my.cnf make sofware not response
max_connections=20000  -- too large; make it only 200
query_cache_size=1G    -- REALLY BAD! -- make it only 50M
table_open_cache=10048  -- too high; try 3000
long_query_time=7  -- Lower to 2, turn on slowlog, keep an eye on it
innodb_buffer_pool_size=10G  -- OK with 16GB of RAM; not ok with 5GB of RAM


On 100

It is not practical, nor efficient, to try perform 100 queries simultaneously.  Because of that, there is no way to "configure" it into existence.  It is better to do...


Combine all the information into a single AJAX call -- the back and forth for AJAX is non-trivial, possibly even more costly than the database queries themselves.
If all the INSERTs are into the same table, then use a single "batch" INSERT with 100 rows.  This will run 10 times as fast as a 100 1-row INSERTs.


If it is not 100 similar inserts, please provide more details about the queries.