>Are there a lot of tuples in the table that have been inserted or
updated by still-open transactions?
Yes, there are likely to be inserts. That table is a log capture table
used by our replication software, so essentially every
update/delete/insert will have a record inserted into the table. It has no
updates. The only thing that deletes from it is the process that had all
the semop calls.
We¹ll look into the postgres minor upgrade and recompile, thanks.