- Use of memory maps. A memory map is where you do a one-off system call and this returns a memory pointer to file cache. This means that when accessing a file, instead of using the traditional call to the read() or write() function, which involve a system call, we simply access memory. There are restrictions and limitations to how much we can use this, but the overall effect is that we do fewer calls to read() and write() and hence fewer system calls.
- Group locking. These locks are transient, sometimes for less than a microsecond, and protect the internal integrity of the database during CRUD operations. They should not be confused with any other sort of locking we perform , for example read locks initiated by READU are something very different. In the past, we have used a locking type which involved a system call. We now use a memory based locking scheme that only requires a system call if the lock is busy.