> Unique indexes slow inserts since db has to acquire a full table lock
An INSERT never results in a full table lock (as in "the lock would prevent other inserts or selects on the table)
Any expression used in the WHERE clause that isn't indexed will probably result in a Seq Scan. CASE expressions are no different than e.g. a function call regarding this.
A stable function marked as "STABLE" (or even immutable) can be optimized differently (e.g. can be "inlined"), so yes that's a good recommendation.
Can you provide more details? Inserting with unique indexes do not lock the table. Case statements are ok in where clause, use expression indexes to index it
What I already know
- Unique indexes slow inserts since db has to acquire a full table lock
- Case statements in Where break query planner/optimizer and require full table scans
- Read only postgres functions should be marked as `STABLE PARALLEL SAFE`