How to solve a problem when copying a table in PostgreSQL?

Question

PostgreSQL

There is a DB, the backup copy is removed every day. But lately there have been errors when deploying a copy. Data duplication errors began to appear in the dump, although no duplicates were found on the original. After digging deeper, I found out that when pg_dump is launched, the COPY command is called. As a result, I got an interesting picture

# copy my_table (id, filter_state_id, analytic_pack, view_type, detail_type, top, 
       params_json, code, name) to '/tmp/copy.txt';
$ cat /tmp/copy.txt | grep 43727
43727   4425    AnyData     1       1       7                       AnyName
43727   4425    AnyData     1       1       7                       AnyName

# select * from my_table where id=43727;
  id   | filter_state_id | analytic_pack | view_type | detail_type | top | params_json | code |     name     
-------+-----------------+---------------+-----------+-------------+-----+-------------+------+--------------
 43727 |            4425 | AnyData   |         1 |           1 |   7 |             |      | AnyName
(1 row)

PostgreSQL version: 9.4
Actually the question is: how can this be, where can the COPY command take a duplicate record from.
I checked it on another table, where there is data versioning, it turned out that under one Id there are identical records but different versions.

Answer 1

COPY has an OIDS parameter,
try to dump/restore it with your hands