How to fix Program limit exceeded in PostgreSQL

ERROR: number of columns (1664) exceeds limit (1600)
ERROR: index row size 3500 exceeds maximum 2712
ERROR: index row requires 10216 bytes, maximum size is 8191
ERROR: too many arguments for function
ERROR: stack depth limit exceeded

-- Before: one table with 1700+ columns
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  col1 text, col2 text, ... col1700+ text
);

-- After: split into two tables
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  col1 text, col2 text, ... col800 text
);

CREATE TABLE user_extended_attrs (
  user_id INT PRIMARY KEY REFERENCES users(id),
  col801 text, col802 text, ... col1700 text
);

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name text,
  email text,
  metadata JSONB  -- store optional/sparse columns here
);

-- Instead of indexing the full value directly:
CREATE INDEX idx_large_text ON my_table (large_text_column);

-- Create an index on a hash of the value:
CREATE INDEX idx_large_text_hash ON my_table USING BTREE (
  md5(large_text_column)
);

-- Or use full-text search for text columns:
CREATE INDEX idx_full_text ON my_table USING GIN (to_tsvector('english', large_text_column));

-- Bad: thousands of values
DELETE FROM my_table WHERE id IN (1, 2, 3, ..., 10000);

-- Good: use a temporary table and join
CREATE TEMP TABLE ids_to_delete AS SELECT * FROM (VALUES (1), (2), (3), ...) AS t(id);
DELETE FROM my_table WHERE id IN (SELECT id FROM ids_to_delete);
DROP TABLE ids_to_delete;

-- Instead of 100+ nested subqueries, use CTEs:
WITH layer1 AS (
  SELECT * FROM table1 WHERE condition1
),
layer2 AS (
  SELECT * FROM layer1 WHERE condition2
),
layer3 AS (
  SELECT * FROM layer2 WHERE condition3
)
SELECT * FROM layer3;

SET max_stack_depth = '4MB';