Copy a postgres database without LOCK permissions - database

Question

I need to copy a postgres DB from one server to another, but the credentials I have do not have permission to lock the database so a pg_dump fails. I have full read/update/insert rights to the DB in question.
How can I make a copy of this database? I'm not worried about inconsistencies (it is a small database on a dev server, so minimal risks of inconsistencies during the extract)
[edit] Full error:
$ pg_dump --username=bob mydatabase > /tmp/dump.sql
pg_dump: SQL command failed
pg_dump: Error message from server: ERROR: permission denied for relation sl_node
pg_dump: The command was: LOCK TABLE _replication.sl_node IN ACCESS SHARE MODE

Answer 1

ERROR: permission denied for relation sl_node
This is your real problem.
Make sure the user bob has SELECT privilege for _replication.sl_node. Is that by any chance a Slony system table or something?

Answer 2

This worked for me
sudo -u postgres pg_dump -Fc -c db_name > file_name.pgdump
Then create a DB and run pg_restore it:
sudo -u postgres /usr/local/pgsql/bin/pg_restore -U postgres -d db_name -v file_name.pgdump

Answer 3

pg_dump doesn't lock the entire database, it does get an explicit lock on all the tables it is going to dump, though. This lock is taken in "access share mode", which is the same lock level required by a SELECT statement: it's intended just to guard against one of the tables being dropped between it deciding which tables to dump and then getting the data.
So it sounds like your problem might actually be that it is trying to dump a table you don't have permission for? PostgreSQL doesn't have database-level read/update/insert rights, so maybe you're just missing the select privilege from a single table somewhere...
As Frank H. suggested, post the full error message and we'll try to help decode it.

Answer 4

You need SELECT permissions (read) on all database objects to make a dump, not LOCK permissions (whatever that may be). What's the complete error message when you start pg_dump to make a dump?

Answer 5

https://forums.aws.amazon.com/thread.jspa?threadID=151526
this link helped me a lot. It refers to another one,
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.PostgreSQL.CommonDBATasks.html#Appendix.PostgreSQL.CommonDBATasks.PostGIS
I first change the ownship to rds_superuser, then paste this piece of code,
CREATE FUNCTION exec(text) returns text language plpgsql volatile AS $f$
BEGIN EXECUTE $1; RETURN $1; END; $f$;
SELECT exec('ALTER TABLE ' || quote_ident(s.nspname) || '.' || quote_ident(s.relname) || ' OWNER TO rds_superuser')
FROM (
SELECT nspname, relname
FROM pg_class c JOIN pg_namespace n ON (c.relnamespace = n.oid)
WHERE nspname in ('tiger','topology') AND
relkind IN ('r','S','v') ORDER BY relkind = 'S')
s;
thereafter, I am able to dump my whole database.

Answer 6

Did you run 'pg_dump' with the correct -U (user who owns that db) ? If yes, then just like other poster said, check the permissions.
HTH

Answer 7

This worked for me -d dbname -n schemaname
pg_dump -v -Fc -h <host> -U <username> -p -d <db_name> -n <schema_name> > file_name.pgdump
default schema is public