Thread: backend_xid and backend_xmin

backend_xid and backend_xmin

From
Satalabaha Postgres
Date:
  Hi All,

I would like to understand the possible causes for backend_xmin getting populated  in pg_stat_activity. Can someone throw some light on this?

Re: backend_xid and backend_xmin

From
Laurenz Albe
Date:
On Thu, 2022-12-08 at 21:01 +0530, Satalabaha Postgres wrote:
> I would like to understand the possible causes for backend_xmin getting
> populated  in pg_stat_activity. Can someone throw some light on this?

"backend_xid" is set when the session has an open transaction that has
modified data and therefore got a transaction ID.

"backend_xmin" is set if there is an active snapshot held by the session:
- there is a running query
- there is an open transaction with an open cursor
- there is an open transaction with isolation level REPEATABLE READ or higher

Yours,
Laurenz Albe
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