RE: row filtering for logical replication

On Wed, Nov 10, 2021 10:48 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Tue, Nov 9, 2021 at 2:22 PM houzj.fnst@fujitsu.com wrote:
> >
> > On Fri, Nov 5, 2021 4:49 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > On Fri, Nov 5, 2021 at 10:44 AM Peter Smith <smithpb2250@gmail.com> wrote:
> > > >
> > > > PSA new set of v37* patches.
> > > 3.
> > > - | ColId
> > > + | ColId OptWhereClause
> > >   {
> > >   $$ = makeNode(PublicationObjSpec);
> > >   $$->pubobjtype = PUBLICATIONOBJ_CONTINUATION;
> > > - $$->name = $1;
> > > + if ($2)
> > > + {
> > > + $$->pubtable = makeNode(PublicationTable); $$->pubtable->relation
> > > + = makeRangeVar(NULL, $1, @1); $$->pubtable->whereClause = $2; }
> > > + else { $$->name = $1; }
> > >
> > > Again this doesn't appear to be the right way. I think this should
> > > be handled at a later point.
> >
> > I think the difficulty to handle this at a later point is that we need
> > to make sure we don't lose the whereclause. Currently, we can only
> > save the whereclause in PublicationTable structure and the
> > PublicationTable is only used for TABLE, but '| ColId' can be used for
> > either a SCHEMA or TABLE. We cannot distinguish the actual type at
> > this stage, so we always need to save the whereclause if it's NOT NULL.
> >
> 
> I see your point. But, I think we can add some comments here indicating that
> the user might have mistakenly given where clause with some schema which we
> will identify later and give an appropriate error. Then, in
> preprocess_pubobj_list(), identify if the user has given the where clause with
> schema name and give an appropriate error.
> 

OK, IIRC, in this approach, we need to set both $$->name and $$->pubtable in
'| ColId OptWhereClause'. And In preprocess_pubobj_list, we can add some check
if both name and pubtable is NOT NULL.

the grammar code could be:

| ColId OptWhereClause
{
    $$ = makeNode(PublicationObjSpec);
    $$->pubobjtype = PUBLICATIONOBJ_CONTINUATION;

    $$->name = $1;
+    /* xxx */
+    $$->pubtable = makeNode(PublicationTable);
+    $$->pubtable->relation = makeRangeVar(NULL, $1, @1);
+        $$->pubtable->whereClause = $2;
    $$->location = @1;
}

preprocess_pubobj_list
...
else if (pubobj->pubobjtype == PUBLICATIONOBJ_REL_IN_SCHEMA ||
pubobj->pubobjtype == PUBLICATIONOBJ_CURRSCHEMA)
{
    ...
+    if (pubobj->name &&
+        (!pubobj->pubtable || !pubobj->pubtable->whereClause))
            pubobj->pubobjtype = PUBLICATIONOBJ_REL_IN_SCHEMA;
    else if (!pubobj->name && !pubobj->pubtable)
            pubobj->pubobjtype = PUBLICATIONOBJ_CURRSCHEMA;
    else
            ereport(ERROR,
                            errcode(ERRCODE_SYNTAX_ERROR),
                            errmsg("invalid schema name at or near"),
                            parser_errposition(pubobj->location));
}


Best regards,
Hou zj