This answer is only for Linux Beginners.
Assuming initially the DB user didn’t have file/folder(directory) permission on the client side.
Let’s constrain ourselves to the following:
User: postgres
Purpose: You wanted to (write to / read from) a specific folder
Tool: psql
Connected to a specific database: YES
FILE_PATH: /home/user/training/sql/csv_example.csv
Query: copy (SELECT * FROM table_name TO FILE_PATH, DELIMITER ',' CSV HEADER;
Actual Results: After running the query you got an error : Permission Denied
Expected Results: COPY COUNT_OF_ROWS_COPIED
Here are the steps I’d follow to try and resolve it.
- Confirm the FILE_PATH permissions on your File system.
Inside a terminal to view the permissions for a file/folder you need to long list them by entering the command ls -l.
The output has a section that shows sth like this -> drwxrwxr-x
Which is interpreted in the following way:
TYPE | OWNER RIGHTS | GROUP RIGHTS | USER RIGHTS
rwx (r: Read, W: Write, X: Execute)
TYPE (1 Char) = d: directory, -: file
OWNER RIGHTS (3 Chars after TYPE)
GROUP RIGHTS (3 Chars after OWNER)
USER RIGHTS (3 Chars after GROUP)
- If permissions are not enough (Ensure that a user can at least enter all folders in the path you wanted path) —
x.
This means for FILE_PATH, All the directories (home , user, training, sql) should have at least an x in the USER RIGHTS.
- Change permissions for all parent folders that you need to enter to have a
x. You can usechmod rights_you_want parent_folder
Assuming /training/ didn’t have an execute permission.
I’d go the user folder and enter chmod a+x training
- Change the destination folder/directory to have a
wif you want to write to it. or at least arif you want to read from it
Assuming /sql didn’t have a write permission.
I would now chmod a+w sql
- Restart the postgresql server
sudo systemctl restart postgresql - Try again.
This would most probably help you now get a successful expected result.
COPY dept
FROM '/media/rayhan/CSE/PostgreSQL/csv_file/dept.csv'
DELIMITER ',' CSV HEADER;
Running this query produce following error. I’ve changed the file extension from .csv to .txt, but same error occurs. Help me to solve this problem. I’m using PostgreSQL version 9.5.12. Thanks in advance.
ERROR: could not open file
«/media/rayhan/CSE/PostgreSQL/csv_file/dept.txt» for reading:
Permission denied
********** Error **********
ERROR: could not open file
«/media/rayhan/CSE/PostgreSQL/csv_file/dept.csv» for reading:
Permission denied SQL state: 42501
asked May 10, 2018 at 13:14
0
I was getting same issue when I was connecting from client to remote postgres server. I changed copy to copy and it worked.
In your case it would be
COPY dept
FROM ‘/media/rayhan/CSE/PostgreSQL/csv_file/dept.csv’
DELIMITER ‘,’ CSV HEADER;
answered Dec 13, 2019 at 10:00
Prasad LelePrasad Lele
3542 silver badges9 bronze badges
It seems that, The PostgreSQL process doesn’t have the permission to access your «csv», find the username which started the PostgreSQL Service and then give the read permission to PG service user «using chmod» at Linux level.
If still facing issue then, change the permission as below:
chmod a+rX /media
chmod a+rX /media/rayhan
chmod a+rX /media/rayhan/CSE
chmod a+rX /media/rayhan/CSE/PostgreSQL
chmod a+rX /media/rayhan/CSE/PostgreSQL/csv_file
chmod a+rX /media/rayhan/CSE/PostgreSQL/csv_file/dept.csv
Now try again to use COPY.
answered May 10, 2018 at 13:24
3
A last-minute website error is always frustrating.
PostgreSQL database queries often end up in errors with code 42501.
This PostgreSQL error 42501 usually occurs when an underprivileged user queries a database. This can be tricky to troubleshoot.
That’s why we often get requests to fix PostgreSQL errors as a part of our Server Management Services.
Today, let’s have a look into the error 42501 and see how our Support Engineers fix it for our customers.
When does PostgreSQL error 42501 occur?
Before moving on to the error 42501, let’s first see more about PostgreSQL.
PostgreSQL is one of the versatile database management systems. It comes handy for developers to build applications, server administrators to protect data and so on. In other words, PostgreSQL is a highly extensible database system.
The error code 42501 denotes insufficient privilege for the database user. But, there can be many reasons that lead to this error.
1. Insufficient privilege for the user
Usually, the 42501 error occurs when a PostgreSQL user with insufficient privileges makes a query on a database.
This indicates that the database user executed an operation, for which the user has no rights.
For database management, the user needs enough rights over the database.
When one of our customers was trying to query a database table in a PostgreSQL tool like pgAdmin, it ended up in error 42501.
The error message was
By default, in the PostgreSQL database, the user restoring the database will have the database ownership. For instance, when restoring a database as the root user, all objects will be under root ownership. And if another user is running any query on this database, it shows the 42501 error.
2. SELinux setting
Sometimes, the SELinux setting in the server can also cause an insufficient privilege error.
SELinux is a security architecture that is a part of Linux kernel. In SELinux, access and transition rights of a user, application, process, and file are all defined. Thus, if SELinux is enabled it affects the user privileges then the database query can end up in a 42501 error.
Fix for 42501 permission denied error
When our customers approach us with this error, our Support Team first checks the reasons that cause this error. The major reasons are insufficient user privilege and SELinux settings.
Now, let’s see how our Support Team fixes this error.
1.Granting Privilege to a user
First and foremost, when a customer approaches us with a 42501 error, we check the database user privileges already given.
If the user lacks enough permission, then we change it accordingly.
Mostly, the user does not have privileges over the requested tables.
In this case, we give privileges to the user over the requested tables using the command.
GRANT SELECT ON table_name TO PUBLIC;This command gives all privileges over the table to the public, hence anyone can use it.
But, some customers prefer giving privileges only to a few users.
In this case, to give table access only to certain users, we use the command.
GRANT SELECT ON table_name TO user_name;After giving privileges to the user, our Support Team executes the query once again. This ensures that the error is fixed.
Similarly, if the root user restored the dump file, this can cause insufficient privilege for the database user.
That is, if the root user restores the database using pg_dump --no-owner then the root user who restored the database will have all privileges.
So, we always restore the database using the login of the desired user. Then, this user will have all privileges over the database.
2. Disabling SELinux
In some cases, the user has enough privilege over the database and still the database query show 42501 error. Here, the SELinux can be the reason causing the error.
After considering other security settings, our Support Team disables this feature using the command.
selinuxenabled && echo enabled || echo disabled[Still having trouble in fixing PostgreSQL errors? – We will fix it for you.]
Conclusion
In short, the PostgreSQL error 42501 occurs mainly due to insufficient privileges for database user for running query. We saw how our Support Engineers fixed this error for our customers.
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var google_conversion_label = «owonCMyG5nEQ0aD71QM»;
I am very new to postgres so please my apologies in advance if I sound naive. I am still trying to learn. I am trying to create a readonly role and then create a role and assign readonly role to the user. I logged in as postgres user
CREATE ROLE readonly;
GRANT CONNECT ON DATABASE test_db TO readonly;
GRANT USAGE ON SCHEMA public TO readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readonly;
CREATE USER readonlyuser WITH PASSWORD 'read123';
grant readonly to readonlyuser;
Now I can login as user readonlyuser but I can’t read data from any tables. I get error SQL Error [42501]: ERROR: permission denied for table.
Any help would be appreciated.
asked Jan 14, 2021 at 6:39
The ALTER DEFAULT PRIVILEGES statement you ran will only affect tables created by postgres. If a different user creator creates the tables, you need
ALTER DEFAULT PRIVILEGES FOR ROLE creator IN SCHEMA public GRANT SELECT ON TABLES TO readonly;
answered Jan 14, 2021 at 7:37
Laurenz AlbeLaurenz Albe
42.8k4 gold badges36 silver badges60 bronze badges
Login : sudo -u postgres psql
Select db : c yourDbName
View all table dt;
grant youUserName to postgres;
(permission related error then use this command)
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO {serverName};
answered Jul 6, 2022 at 12:37
For me, the problem was that I was using the free tier of ElephantSql.com (a great website BTW), and I used (way) more than the allocated 20 MB free quota.
I was able to make a select query, but an insert one failed with the error permission denied for table.
answered Jan 25 at 1:13
Я решил эту проблему, создав в базе данных PostgreSQL папку с именем Database, где я сохраняю все файлы данных, с которыми я хочу работать. Я использую pgAdmin4 на Mac и Windows. Принимая во внимание, что это довольно просто найти корзину в Windows, это немного сложно найти его на Mac, потому что библиотека, где хранится корзина, скрыта. Попробуйте сохранить ваши файлы на C:ProgramFilesPostgreSQL10binDatabase если вы используете Windows и /Library/PostgreSQL/10/bin/Database/если вы используете Mac. Библиотеку можно найти, нажав command+shift+g и введите ~/Library на ходу в папку. Ваш Mac потребует ваш пароль для внесения изменений в библиотеке. После сохранения ваших файлов данных здесь ваш код на pgAdmin4 должен выглядеть следующим образом:
COPY console_games FROM 'C:ProgramFilesPostgreSQL10binDatabaseConsoleGames.csv' DELIMITER ',' CSV HEADER;
или же
COPY console_games FROM '/Library/PostgreSQL/10/bin/Database/ConsoleGames.csv' DELIMITER ',' CSV HEADER;