Finally we solved our problem by using a kind of trick
We have 2 kind of table : online table for read and temp table to mass insert our data
We work on the temp tables (5 different tables) to insert every data without any index that goes really fast compared to the previous method
then we create index on these tables simultanously,
then we drop online tables(also 5 tables) and rename the temp tables to online (takes less than 1 sec)
This is the faster way to insert our data that we found.
On our config it goes pretty fast, we reduce our execution time to 50% and there is no more need of many maintenance on the database.
Thanks for all answer that you give us.