Re: zstd compression for pg_dump

On Sat, Feb 25, 2023 at 01:44:36PM +0900, Michael Paquier wrote:
> On Fri, Feb 24, 2023 at 01:18:40PM -0600, Justin Pryzby wrote:
> > This is a draft patch - review is welcome and would help to get this
> > ready to be considererd for v16, if desired.
> > 
> > I'm going to add this thread to the old CF entry.
> > https://commitfest.postgresql.org/31/2888/
> 
> Patch 0003 adds support for the --long option of zstd, meaning that it
> "enables long distance matching with #windowLog".  What's the benefit
> of that when it is applied to dumps and base backup contents?

It (can) makes it smaller.

+           The <literal>long</literal> keyword enables long-distance matching
+           mode, for improved compression ratio, at the expense of higher memory
+           use.  Long-distance mode is supported only for 

+        With zstd compression, <literal>long</literal> mode may allow dumps
+        to be significantly smaller, but it might not reduce the size of
+        custom or directory format dumps, whose fields are separately compressed.

Note that I included that here as 003, but I also have an pre-existing
patch for adding that just to basebackup.

-- 
Justin