Avoid Unnecessary UPDATEs

An UPDATE is implemented as a combination of DELETE and INSERT. Try to design your model and loading routines to avoid UPDATEs of large tables.

Example 1: When storing full history of data, do not update old records with an end-of-validity timestamp. Instead, insert new versions only and retrieve end-of-validity timestamp at query time when necessary.

Example 2: When computing derived columns for existing records, consider inserting them into a separate table, rather than updating existing records.