Berkeley DB

Transaction Throughput

Generally, the speed of a database system is measured by the transaction throughput, expressed as the number of transactions per second. The two gating factors for Berkeley DB performance in a transactional system are usually the underlying database files and the log file. Both are factors because they require disk I/O, which is slow relative to other system resources such as CPU.

In the worst-case scenario:

• Database access is truly random and the database is too large to fit into the cache, resulting in a single I/O per requested key/data pair.

• Both the database and the log are on a single disk.

This means that for each transaction, Berkeley DB is potentially performing several filesystem operations:

• Disk seek to database ...