ERROR: MultiXactId 3268957 has not been created yet -- apparent wraparound after missused pg_resetxlogs

Hi,

I’m facing a problem with a PostgreSQL 9.6.2 reporting this error when
selecting a table

ERROR: MultiXactId 3268957 has not been created yet -- apparent wraparound

The root cause is not a Postgres bug but a buggy person that used
pg_resetxlogs obviously without reading or understanding the documentation.

I’m trying to extract data from the db to create a new one ;-)

But pg_dump logically end with the same error.

I’ve seen the row with t_max = 3268957 page_inspect, I might use it to
extract row from the page, but this will not be quite easy.

Is there a way to change the t_max to a value that won’t fire the error,
with this row.

Could pg_filedump be used in this problem configuration.

As usual, xlogs where deleted even stored in a directory named pg_wal L (
I made the change before 10 ) and xlogs reseted by the same person that
commented the backup months ago.

Hopefully, this is not a production database :-D but the user want to start
qualification of the new application version today .. no luck for him.

Any advice of how to extract data is welcome.

At least, there is something to learn, renaming pg_xlog to pg_wal won’t
stop everybody :-/

Regards.

Alain Radix