如何提高写入数据库的性能？

We log values and we only log them once in a table. When we add values to the table we have to do a look up everytime to see if it needs to insert the value or just grab the id. We have an index on the table (not on the primary key) but there are about 350,000 rows (so it is taking 10 seconds to do 10 of these values). We log values and we only log them once in a ta