Re: Persist MVCC forever - retain history

On 02.07.2020 21:55, Mitar wrote:
> Hi!
>
> (Sorry if this was already discussed, it looks pretty obvious, but I
> could not find anything.)
>
> I was thinking and reading about how to design the schema to keep
> records of all changes which happen to the table, at row granularity,
> when I realized that all this is already done for me by PostgreSQL
> MVCC. All rows (tuples) are already stored, with an internal version
> field as well.
>
> So I wonder, how could I hack PostgreSQL to disable vacuuming a table,
> so that all tuples persist forever, and how could I make those
> internal columns visible so that I could make queries asking for
> results at the particular historical version of table state? My
> understanding is that indices are already indexing over those internal
> columns as well, so those queries over historical versions would be
> efficient as well. Am I missing something which would make this not
> possible?
>
> Is this something I would have to run a custom version of PostgreSQL
> or is this possible through an extension of sort?
>
>
> Mitar
>
Did you read this thread:
https://www.postgresql.org/message-id/flat/78aadf6b-86d4-21b9-9c2a-51f1efb8a499%40postgrespro.ru
I have proposed a patch for supporting time travel (AS OF) queries.
But I didn't fill a big interest to it from community.