Re: Increased storage size of jsonb in pg15

On 12/28/23 12:41, Sean Flaherty wrote:
> I'm rather new to the mailing list, are there any additional steps I 
> should take (i.e. posting to pgsql-hackers, etc.)?
> 

For what purpose? You are seeing differences in compression strategies 
between lz4 and pglz. The 'fix' would be to go back to pglz.

> 
> On Thu, Dec 28, 2023 at 11:23 AM Adrian Klaver 
> <adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>> wrote:
> 
>     On 12/28/23 09:13, Sean Flaherty wrote:
>      > Follow-up:
>      > Working with AWS, we found that starting in RDS Postgres 15, the
>      > default_toast_compression parameter is set to use lz4 compression
>      > instead of pglz.  This resulted in the increased json storage
>     size we
>      > were seeing.
>      >
>      > I have been able to reproduce the increased storage size on RDS
>     Postgres
>      > and using my local docker instance of postgres 15.5 by changing the
>      > local default_toast_compression value in postgresql.conf.
>      >
>      > I have attached the test script we use to create a table, insert
>     some
>      > test records and a query to test the JSON data size on disk.
> 
>     I can confirm I see the same results using Postgres 16 installed from
>     the PGDG repo on Ubuntu 22.04. That the lz4 data size is greater then
>     the pglz data size.
> 
>      >
>      >
>      > Kind regards,
>      > Sean
>      >
> 
> 
>     -- 
>     Adrian Klaver
>     adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
> 

-- 
Adrian Klaver
adrian.klaver@aklaver.com