How to diagnose and fix the 54023 too_many_arguments error code in Postgres. 

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The 54023 too_many_arguments error code in PostgreSQL occurs when a function is invoked with more arguments than it is designed to accept, or when defining a function with more than the maximum allowed number of arguments. By default, PostgreSQL functions can have up to 100 input arguments. Here are several examples of how this error might occur and how to resolve it:

  1. Defining a Function with Too Many Arguments:
    If you attempt to create a function with more than 100 arguments, PostgreSQL will raise the too_many_arguments error.
   CREATE FUNCTION my_function(arg1 int, arg2 int, ..., arg101 int) RETURNS void AS $$
   BEGIN
     -- function body
   END;
   $$ LANGUAGE plpgsql;

To fix this, you should redesign your function to accept fewer arguments. One approach is to use composite types or arrays to pass multiple values in a single argument:

   CREATE TYPE my_composite_type AS (field1 int, field2 int, ...);

   CREATE FUNCTION my_function(args my_composite_type) RETURNS void AS $$
   BEGIN
     -- function body where you can access args.field1, args.field2, etc.
   END;
   $$ LANGUAGE plpgsql;
  1. Calling a Function with Too Many Arguments:
    When calling a function, providing more arguments than the function expects will result in the too_many_arguments error.
   -- Assuming my_function is defined to take 3 arguments
   SELECT my_function(1, 2, 3, 4);

To resolve this error, ensure that you call the function with the correct number of arguments:

   SELECT my_function(1, 2, 3);
  1. Passing Too Many Arguments in a Trigger Function:
    If you create a trigger function that mistakenly attempts to accept arguments (trigger functions should not accept any arguments), you may encounter the too_many_arguments error when the trigger is fired.
   CREATE FUNCTION my_trigger_function() RETURNS trigger AS $$
   BEGIN
     -- trigger function body
   END;
   $$ LANGUAGE plpgsql;

   CREATE TRIGGER my_trigger
   BEFORE INSERT ON my_table
   FOR EACH ROW
   EXECUTE FUNCTION my_trigger_function(arg1); -- Incorrectly passing an argument

Trigger functions are invoked by the trigger mechanism itself and do not accept arguments passed in this way. To fix this, remove the argument:

   CREATE TRIGGER my_trigger
   BEFORE INSERT ON my_table
   FOR EACH ROW
   EXECUTE FUNCTION my_trigger_function();

When diagnosing the 54023 too_many_arguments error, review the function definition to ensure it does not exceed the 100 argument limit. When calling functions, verify that the number of arguments provided matches the number expected by the function. If you are working with a large number of parameters, consider using composite types, arrays, or JSON to encapsulate multiple values into a single argument.

For more details on function creation and argument limits, you can refer to the PostgreSQL documentation on creating functions. If you need to pass a large number of parameters, you can learn more about composite types in the PostgreSQL documentation on composite types.

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