Database

Fundamentals

https://tontinton.com/posts/database-fundementals/ https://www.thenile.dev/blog/transaction-isolation-postgres

The simplest database can be just writing to a file and then reading the file to get the results back. Databases, however, are more advanced, in order to provide

• Durability
• Atomicity
• Isolation
• Performance

The safety aspects of databases are refer to being ACID.

ACID

ACID is an acronymn and refers to the database’s property of maintaining safe and consistent behavior during transactions. Transactions are a series of statements for interacting with databases, whether it be a series of writes, reads, or both.

Atomicity: transactions must either fail or succeed, no in-between. Consistency: transactions must bring a database from one consistent state to another. Isolation: transactions can be safely executed concurrently, that is the same result could be obtained if the transactions were executed sequentially. Durability: completed transactions should never disappear, for example in the event of a crash, and should store in non-volatile storage.

Storage Engine

Databases have to fast, and the fastest way is to rely on caches and memory, of which the L1 cache is the fastest.