What gets TOASTed in Postgres

Insert 2,000 copies of the letter x into a table with an int ID and a text column, and Postgres stores all 2,000 bytes uncompressed. Insert 2,001, and Postgres compresses the value to 26 bytes with LZ4. That one extra byte is enough to trigger TOAST , the part of Postgres that compresses values once their row gets too big, and moves them out of the row when compressing isn’t enough.