Postgres 9.4.9 has a fix in it's release notes which reads (emphasis mine):

Prevent possible failure when vacuuming multixact IDs in an installation that has been pg_upgrade'd from pre-9.3 (Andrew Gierth, Álvaro Herrera)

The usual symptom of this bug is errors like "MultiXactId NNN has not been created yet -- apparent wraparound".

I am currently chasing errors in PG 9.4.5 which read:

2019-10-19 15:37:17 EDT [13024]: [1-1] ERROR:  MultiXactId 1074790449 does no longer exist -- apparent wraparound

Does the above fix in PG 9.4.9 address the error I am getting?

  • dba.stackexchange.com/questions/143516/… - This question led me to look at PG 9.4.9 . I have tried to trace through the old mailing list threads to determine the answer to my own question but I'm not immediately seeing this one way or the other.
    – Freiheit
    Oct 21, 2019 at 15:41
  • 2
    Good question. I'd assume that it could lead to both of these errors, but I am not sure. You should always install the latest minor release anyway; running 9.4.9 borders on criminal negligence. Try and see! Oct 22, 2019 at 6:19

1 Answer 1


I upgraded to PG 9.6.8. This particular environment is a legacy application that runs on an "appliance" style deployment so I'm forced into only updating to certain versions. 9.6.8 was the smallest increment I could take.

The initially appeared to have solved the MultiXactId xxxx does no longer exist problem with some simple queries. Subsequent queries to create indexes failed with the original error.

  • 1
    You should really be upgrading to the latest 9.6 version.
    – user1822
    Oct 28, 2019 at 14:40
  • Thanks for the reminder @a_horse_with_no_name . Once this wraparound problem is solved, there is some version of PG 10 that I can upgrade to and I'll be making plans to push it forward.
    – Freiheit
    Oct 28, 2019 at 14:45

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