The error is harmless but to get rid of it, I think you need to break this restore into two commands, as in:
dropdb -U postgres mydb && \
pg_restore --create --dbname=postgres --username=postgres pg_backup.dump
The --clean
option in pg_restore doesn't look like much but actually raises non-trivial problems.
For versions up to 9.1
The combination of --create
and --clean
in pg_restore options used to be an error in older PG versions (up to 9.1). There is indeed some contradiction between (quoting the 9.1 manpage):
--clean
Clean (drop) database objects before recreating them
and
--create
Create the database before restoring into it.
Because what's the point of cleaning inside a brand-new database?
Starting from version 9.2
The combination is now accepted and the doc says this (quoting the 9.3 manpage):
--clean
Clean (drop) database objects before recreating them. (This might generate some harmless error messages, if any objects were not present in the destination database.)
--create
Create the database before restoring into it. If --clean is also specified, drop and recreate the target database before connecting to it.
Now having both together leads to this kind of sequence during your restore:
DROP DATABASE mydb;
...
CREATE DATABASE mydb WITH TEMPLATE = template0... [other options]
...
CREATE SCHEMA public;
...
CREATE TABLE...
There is no DROP
for each individual object, only a DROP DATABASE
at the beginning. If not using --create
this would be the opposite.
Anyway this sequence raises the error of public
schema already existing because creating mydb
from template0
has imported it already (which is normal, it's the point of a template database).
I'm not sure why this case is not handled automatically by pg_restore
. Maybe this would cause undesirable side-effects when an admin decides to customize template0
and/or change the purpose of public
, even if we're not supposed to do that.
I found the line in the toc.dat file that made the call and unpacked
the .dat.gz file to find it only contains "\." (sans the quotes) in
it.
\.
is not a command, it marks the end of data in a COPY stream.
If the corresponding data file inside the dump contains only that, then the source table was empty.
Also note that you can pg_restore --list
to list the contents of a dump in directory or compressed format.
You may also restore the contents of an individual table into an SQL file rather than in the target database, then modify that file as convenient, and play it into the target. See the pg_restore manpage for more.
Best Answer
You need to read the documentation for the version you are using.
Since v12,
-f -
is mandatory to get output to go to stdout. Having that behavior be obtained just by omitting -d was considered to be confusing. But since you want the output to go to a file, just name that file: