Re: sharing sstate in bitbake-setup

On Wed, 26 Nov 2025 at 17:41, Richard Purdie
<[email protected]> wrote:
linked into every build.
> >
> > I quickly hacked bitbake's cooker.py to try this out:
> >
> > -                dbfile = (self.data.getVar("PERSISTENT_DIR") or
> > self.data.getVar("CACHE")) + "/hashserv.db"
> > +                dbfile = "/home/alex" + "/hashserv.db"
> >
> >
> > And then made two build directories with shared SSTATE_DIR.
> >
> > TL;DR: everything ran smoothly and as expected.
> >
> > I ran overlapping builds, added no-ops to gnu-config recipe to 'force'
> > hash equivalency, and there were no errors or crashes, and sstate was
> > reused as expected.
> >
> > So I think we should do it like this, subject to 'shared-sstate'
> > setting in bitbake-setup, on by default.
>
> PERSISTENT_DIR is *not* designed to be shared between builds. it might
> happen to work but is a really bad idea. Personally, I think those
> cache directory variables and cache layout need redesigning so we
> should probably take the opportunity to do that.

I am not sharing PERSISTENT_DIR. Only the hash equivalency database in
hashserv.db, which I believe is fine because sqlite has locking
mechanisms and is explicitly designed for it.

Alex