Traditional Db with CRUD Ops vs Insert-only Db

Different from file system which is usually (SLR, Save/Load/Remove) where Save is upsert; databases use the concept CRUD which are Create/Read/Update/Delete. These are traditional databases.

There's a kind of databases different from traditional Db, popularly known with Google called insert-only database. The insert-only mode enable higher performance. Below are the performance cost differences in time spent between traditional CRUD and insert-only databases with already compiled indexes.

Ops       CRUD       Insert-only

=========================================

Create    O(1)       O(1)

Read      O(logn)    O(logn)

Update    O(logn)    O(1)  No lookup

Delete    O(logn)    Zero, Doesn't delete

Locking   Long       Zero, No locks

Fragment  Clustered  Continuous on disk

History   No         Yes

From the table above, there are some good points of insert-only database can be seen:

• Constant-time update, coz it write only without lookup
• Zero deletion time, coz it doesn't delete anything
• Never face table locking issue coz ops won't conflict
• Disk fragmentation, continuous write is much better than writing on fragmented disk, even SSD
• History, insert-only db has perfect data change history and useful sometimes