Re: jsonb format is pessimal for toast compression

On 08/14/2014 07:24 PM, Tom Lane wrote:

> We can certainly reduce that.  The question was whether it would be
> worth the effort to try.  At this point, with three different test
> data sets having shown clear space savings, I think it is worth
> the effort.  I'll poke into it tomorrow or over the weekend, unless
> somebody beats me to it.

Note that I specifically created that data set to be a worst case: many
top-level keys, no nesting, and small values.  However, I don't think
it's an unrealistic worst case.

Interestingly, even on the unpatched, 1GB table case, the *index* on the
JSONB is only 60MB.  Which shows just how terrific the improvement in
GIN index size/performance is.


-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com