> On Oct 23, 2020, at 9:52 AM, Ravi Krishna <sravikris...@mail.com> wrote:
>
>> My understanding is that when CONCURRENTLY is specified, Postgres implements
>> the refresh as a series of INSERT, UPDATE,
>> and DELETE statements on the existing view. So the answer to your question
>> is no, Postgres doesn’t create another table and
>> then swap it.
>
> The INSERTS/UPDATE/DELETE happens only for the difference. PG first creates
> a new temp table and then compares it with
> the MV and detects the difference. That is why for CONCURRENTLY, a unique
> index is required on the MV.
Yes, thank you, that’s what I understand too but I expressed it very poorly.
