How to diagnose and fix the 54000 program_limit_exceeded error code in Postgres.

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The 54000 error code in PostgreSQL indicates a program_limit_exceeded error. This error means that some predefined limit in the PostgreSQL system has been exceeded. There are several scenarios where this can occur, such as exceeding the maximum number of columns in a table, the maximum number of arguments in a function, or the size of a data structure.

Here are examples and solutions to resolve the 54000 program_limit_exceeded error:

  1. Too Many Columns in a Table
    PostgreSQL has a limit on the number of columns a table can have, which is typically 1600 columns. Example:
   CREATE TABLE my_table (
       col1 text,
       col2 text,
       ...
       col1601 text -- Exceeds the maximum number of columns
   );

Fix:
Redesign the table structure to have fewer columns, use a more normalized schema, or store some data as JSONB or HSTORE to combine multiple values into a single column.

   CREATE TABLE my_table (
       id serial PRIMARY KEY,
       attributes jsonb -- Stores multiple values in a single column
   );
  1. Too Many Arguments in a Function
    There is a limit on the number of arguments that a function can take, which is typically 100 arguments. Example:
   CREATE FUNCTION my_func(
       arg1 integer,
       arg2 integer,
       ...
       arg101 integer -- Exceeds the maximum number of arguments
   ) RETURNS integer AS $$ ... $$ LANGUAGE sql;

Fix:
Pass a composite type, an array, or a JSONB object that contains multiple values instead of individual arguments.

   CREATE TYPE my_composite_type AS (
       arg1 integer,
       ...
       arg100 integer
   );

   CREATE FUNCTION my_func(args my_composite_type) RETURNS integer AS $$ ... $$ LANGUAGE sql;
  1. Exceeding the Maximum Row Size
    PostgreSQL has a limit on the maximum size of a row, which is typically around 4000 bytes (excluding TOASTable columns). Example:
   CREATE TABLE my_table (
       col1 char(2000),
       col2 char(2000),
       col3 char(2000) -- Combined size of the row exceeds the maximum row size
   );

Fix:
Use variable-length data types like VARCHAR or TEXT that can be TOASTed (The Oversized-Attribute Storage Technique) to compress and store large fields out of the main table area.

   CREATE TABLE my_table (
       col1 text,
       col2 text,
       col3 text
   );

To diagnose the 54000 program_limit_exceeded error:

  • Look at the error message details to understand which limit has been exceeded.
  • Review the SQL statement that caused the error to identify the potential cause, such as an excessively large list of columns, arguments, or row size.

When fixing the error, consider redesigning your database schema or function signatures to comply with PostgreSQL’s limits. You may need to normalize your schema, use different data types, or change how you pass data to functions.

For more detailed information about PostgreSQL’s limits, you can refer to the PostgreSQL documentation. If you need further assistance, consider asking for help on community forums or platforms like Stack Overflow, where many users share their experiences and solutions for dealing with similar issues.

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