How to diagnose and fix the 38003 prohibited_sql_statement_attempted error code in Postgres. 

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The 38003 error code in PostgreSQL, which stands for prohibited_sql_statement_attempted, typically indicates that an SQL statement was executed that is not permitted in the current context. This error is often related to SQL statements that violate the security restrictions of a particular environment, such as within a function or trigger that has been defined with security restrictions.

To diagnose and fix this error, you need to:

  1. Identify the context in which the error occurred. Look at the function, trigger, or other procedural code that was running when the error was raised.
  2. Examine the specific SQL statement that triggered the error. This will involve reviewing the code within your procedural SQL or application logic.
  3. Determine the security restrictions that are in place for the context. For instance, if you’re dealing with a function or trigger, check if it’s defined as SECURITY DEFINER or SECURITY INVOKER, and what permissions the user has.
  4. Modify the SQL statement or adjust the permissions to comply with the security restrictions.

Here are some examples of situations that could lead to a 38003 error and how you might address them:

Example 1: Function with SECURITY DEFINER

If you have a function that is defined with SECURITY DEFINER and it tries to perform an operation that the owner of the function is not allowed to do, you’ll get this error. To fix it, make sure the function owner has the necessary permissions.

CREATE OR REPLACE FUNCTION secure_function() RETURNS void LANGUAGE plpgsql SECURITY DEFINER AS $$
BEGIN
    -- A statement here that the function owner cannot execute
END;
$$;

To fix this, you might need to grant the necessary permissions to the function owner or change the function’s security context.

Example 2: Restricted operation within a SECURITY INVOKER function

If a function is created with SECURITY INVOKER, it will execute with the privileges of the user who calls the function. If that user tries to execute a prohibited statement through the function, PostgreSQL will raise a 38003 error.

CREATE OR REPLACE FUNCTION invoker_function() RETURNS void LANGUAGE plpgsql SECURITY INVOKER AS $$
BEGIN
    -- A statement here that the invoker is not permitted to execute
END;
$$;

In this case, you would need to ensure that any user who is going to invoke this function has the appropriate permissions to perform all the operations within the function.

Example 3: Violating Row-Level Security (RLS) Policies

Row-Level Security (RLS) policies can also lead to 38003 errors if a user attempts to perform an action that is explicitly forbidden by an RLS policy.

To diagnose, check the RLS policies on the table in question:

SELECT * FROM pg_policies WHERE tablename='your_table_name';

To fix, you might need to adjust the RLS policy to allow the operation or ensure that users have the correct roles or permissions that satisfy the policy.

In all cases, the key to resolving a 38003 error is to carefully review the context and the permissions of the user or entity that is attempting to execute the SQL statement. Adjusting the code or the permissions to align with the security model of your PostgreSQL database will resolve the issue.

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