Subject: Re: Understanding JSONB and TOAST tables
To: Wells Oliver <wells.oliver@gmail.com>,
 pgsql-admin <pgsql-admin@postgresql.org>
References: 
 <CAOC+FBX_Zwu_Ck4hgFGy3O0vz_HT0i7=Y-ozBVSe9n4+-28G+A@mail.gmail.com>
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Organization: 2ndQuadrant
Message-ID: <f6189da9-09f5-90fe-9d0e-7bdcb7589bbe@2ndquadrant.com>
Date: Wed, 10 Jun 2020 00:59:19 +0200
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On 2020-06-09 21:48, Wells Oliver wrote:
> Is there documentation that lays out how JSONB columns are stored? I 
> have a Rather Large Table with 37m+ rows with large JSONB objects, its 
> size is about 300mb, but there's an associated TOAST table with a 28GB size.
> 
> Curious how/why PSQL would store JSONB stuff this way.

TOAST is documented here: 
https://www.postgresql.org/docs/current/storage-toast.html.  JSONB is 
handled like any other (variable-size) data type.  You can use the 
per-column storage settings mentioned on that page to perhaps achieve 
different storage outcomes.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services