Solaris includes a range of I/O enhancements that directly benefit databases. Some of the more important optimizations are described in this section.
The pread and pwrite System Calls
Much database activity involves reading from and writing to database tables on disk and to the database log file. The pread (2) and pwrite (2) system calls were introduced into Solaris to eliminate the need for a separate lseek (2) system call to position a file pointer before a read (2) or write (2) system call. Both pread and pwrite take the offset within the file as an additional argument. Eliminating system calls frees up CPU cycles for more useful work.
Kernel Asynchronous I/O
When disk I/O is carried out with the read, pread, write, and ...