How Generalized Inverted Index works internally in Postgre SQL

Regular indexing works on a column level; it indexes the entire column value. But if you want to index each value in one row, then the GIN indexing technique is used. GIN can index each element of JSON stored in a JSONB field.

Internal Mechanics

• How Postgres creates a GIN file physically
• What is the format of that file
• How that file is retrieved in RAM while fetching records
• What data types are used
• How Postgres calculates the exact address of an element of JSON

All these are explained in the article.