Well, it seems we have hit a bug in postgresql 10. We tried running vacuumlo on a database and it complained at some point with a message
Failed to remove lo 64985186: ERROR: large object 64985186 does not exist Removal from database "XXXXX" failed at object 26 of 100. Yet, object 64985186 is neither in pg_largeobject.loid nor in pg_largeobject_metadata.oid Researching similar problems did not yield anything enlightening, except for a comment by Tom Lane that vacuumlo will use an index. That led be to the assumption an index had gone wrong and I did REINDEX ( VERBOSE ) TABLE pg_largeobject_metadata; Which failed with the message ERROR: could not create unique index "pg_largeobject_metadata_oid_index" DETAIL: Key (oid)=(665238) is duplicated. Well, select oid,* from pg_largeobject_metadata where oid=665238; oid | lomowner | lomacl --------+----------+-------- 665238 | 16123 | (1 row) That seemed odd, so I decided to do a FULL VACUUM VACUUM (full, verbose) pg_largeobject_metadata Now I see select oid,* from pg_largeobject_metadata where oid=665238; oid | lomowner | lomacl --------+----------+-------- 665238 | 16123 | 665238 | 16123 | (2 rows) Deleting both would be a no-go, as I cannot INSERT a specific oid to add one back as far as I know. So how do I delete only one of the two? Luckily this is only a test instance, so I'm not totally freaked out now. Note: I randomized the IDs a bit in this post for security reasons, but kept the scale. Please ignore should they be in an unusual range. Thanks, Tobias
