"Persisted" means "stored physically" in this context
It means that the computed value is computed once on insert (and on updates) and stored on disc, so it does not have to be computed again on every select.
Persisted also causes a performance penalty on insert and updates, since the column must be computed, but will increase the performance on subsequent select queries.
So, it depends on your usage pattern, which approach to follow: if you update infrequently, but query a lot, you should set persisted = true.
If you update frequently, or if you do not care about retrieval performance, you should consider setting persisted = false
If column is not persisted then we can't create the indexes on it.
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