RE: Synchronizing slots from primary to standby

On Wednesday, February 28, 2024 2:38 PM Bertrand Drouvot  wrote:
> On Wed, Feb 28, 2024 at 08:49:19AM +0530, Amit Kapila wrote:
> > On Mon, Feb 26, 2024 at 9:13 AM shveta malik 
> wrote:
> > >
> > > On Fri, Feb 23, 2024 at 7:41 PM Bertrand Drouvot
> > >  wrote:
> > > >
> > > > Hi,
> > > > > I think to set secure search path for remote connection, the
> > > > > standard approach could be to extend the code in
> > > > > libpqrcv_connect[1], so that we don't need to schema qualify all the
> operators in the queries.
> > > > >
> > > > > And for local connection, I agree it's also needed to add a
> > > > > SetConfigOption("search_path", "" call in the slotsync worker.
> > > > >
> > > > > [1]
> > > > > libpqrcv_connect
> > > > > ...
> > > > >       if (logical)
> > > > > ...
> > > > >               res = libpqrcv_PQexec(conn->streamConn,
> > > > >
> > > > > ALWAYS_SECURE_SEARCH_PATH_SQL);
> > > > >
> > > >
> > > > Agree, something like in the attached? (it's .txt to not disturb the CF bot).
> > >
> > > Thanks for the patch, changes look good. I have corporated it in the
> > > patch which addresses the rest of your comments in [1]. I have
> > > attached the patch as .txt
> > >
> >
> > Few comments:
> > ===============
> > 1.
> > - if (logical)
> > + if (logical || !replication)
> >   {
> >
> > Can we add a comment about connection types that require
> > ALWAYS_SECURE_SEARCH_PATH_SQL?
> 
> Yeah, will do.
> 
> >
> > 2.
> > Can we add a test case to demonstrate that the '=' operator can be
> > hijacked to do different things when the slotsync worker didn't use
> > ALWAYS_SECURE_SEARCH_PATH_SQL?
> 
> I don't think that's good to create a test to show how to hijack an operator
> within a background worker.
> 
> I had a quick look and did not find existing tests in this area around
> ALWAYS_SECURE_SEARCH_PATH_SQL / search_patch and background worker.

I think a similar commit 11da970 has added a test for the search_path, e.g.

# Create some preexisting content on publisher
$node_publisher->safe_psql(
	'postgres',
	"CREATE FUNCTION public.pg_get_replica_identity_index(int)
	 RETURNS regclass LANGUAGE sql AS 'SELECT 1/0'");    # shall not call

Best Regards,
Hou zj