On Mon, May 20, 2024 at 11:54 AM Christophe Pettus wrote:
>
>
> > On May 20, 2024, at 08:49, PetSerAl wrote:
> > Basically, you need application cooperation to make
> > consistent live database backup.
>
> If it is critical that you have a completely consistent backup as of a
> particular point
> On May 20, 2024, at 08:49, PetSerAl wrote:
> Basically, you need application cooperation to make
> consistent live database backup.
If it is critical that you have a completely consistent backup as of a
particular point in time, and you are not concerned about restoring to a
different
> However, it would be the very same
> database state that any other query would see at that time.
Other queries can use different techniques to prevent this. For
example, lock tables before snapshot, as recommended in documentation.
I understand, that pg_dump can not use that, as it need snapshot
PetSerAl writes:
> My question:
> What happens if not MVCC-safe command committed after snapshot but before
> lock?
Then you'd get a dump that's not exactly consistent with the state
at the time of the snapshot. However, it would be the very same
database state that any other query would see
My question:
What happens if not MVCC-safe command committed after snapshot but before lock?
On Mon, May 20, 2024 at 12:33 PM Guillaume Lelarge
wrote:
>
> Hi,
>
> Le lun. 20 mai 2024 à 11:27, PetSerAl a écrit :
>>
>> How pg_dump interact with not MVCC-safe command
Hi,
Le lun. 20 mai 2024 à 11:27, PetSerAl a écrit :
> How pg_dump interact with not MVCC-safe commands?
>
> As I understand, pg_dump first take snapshot and then lock all tables
> it intended to dump. What happens if not MVCC-safe command committed
> after snapshot but before loc
How pg_dump interact with not MVCC-safe commands?
As I understand, pg_dump first take snapshot and then lock all tables
it intended to dump. What happens if not MVCC-safe command committed
after snapshot but before lock? From comment to pg_dump.c I understand
that it may fail with 'cache lookup
