Re: 13.2.1. Read Committed Isolation Level
| От | David G. Johnston |
|---|---|
| Тема | Re: 13.2.1. Read Committed Isolation Level |
| Дата | |
| Msg-id | CAKFQuwY2=UTnpcuzEhTFKwOHLafS-jUGtxf72R63mjGs66ROxQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | 13.2.1. Read Committed Isolation Level (PG Doc comments form <noreply@postgresql.org>) |
| Ответы |
Re: 13.2.1. Read Committed Isolation Level
|
| Список | pgsql-docs |
On Tue, Jul 16, 2024 at 7:06 AM PG Doc comments form <noreply@postgresql.org> wrote:
Or does it mean that contrary to Read
Committed Isolation Level, uncommitted changes from a parallel transaction
can affect the execution of an INSERT command?
This. Because you are keying off of an unique index that has independent isolation mechanics. Upon attempting to insert a row that will violate the unique constraint enforced by the index the system must wait to see whether the earlier transaction commits. If it doesn't, the insert proceeds. If it does, the conflict clause is evaluated - updating the now committed row (or just doing nothing if that option is specified.)
David J.
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