Package "postgresql-10-toastinfo"

Show storage structure of varlena datatypes in PostgreSQL
This PostgreSQL extension exposes the internal storage structure of
variable-length datatypes, called varlena.

The function pg_toastinfo describes the storage form of a datum:

* null for NULLs
* ordinary for non-varlena datatypes
* short inline varlena for varlena values up to 126 bytes (1 byte header)
* long inline varlena, (un)compressed for varlena values up to 1GiB
(4 bytes header)
* toasted varlena, (un)compressed for varlena values up to 1GiB stored in
TOAST tables

The function pg_toastpointer returns a varlena's chunk_id oid in the
corresponding TOAST table. It returns NULL on non-varlena input.