Re: row filtering for logical replication

On Thu, Jan 20, 2022 at 2:29 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Jan 20, 2022 at 7:51 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> >
> > Here are some review comments for v68-0001.
> >
> >
> > 3. src/backend/replication/pgoutput/pgoutput.c - pgoutput_row_filter_init
> >
> > + /* If no filter found, clean up the memory and return */
> > + if (!has_filter)
> > + {
> > + if (entry->cache_expr_cxt != NULL)
> > + MemoryContextDelete(entry->cache_expr_cxt);
> > +
> > + entry->exprstate_valid = true;
> > + return;
> > + }
> >
> > IMO this should be refactored to have if/else, so the function has
> > just a single point of return and a single point where the
> > exprstate_valid is set. e.g.
> >
> > if (!has_filter)
> > {
> > /* If no filter found, clean up the memory and return */
> > ...
> > }
> > else
> > {
> > /* Create or reset the memory context for row filters */
> > ...
> > /*
> > * Now all the filters for all pubactions are known. Combine them when
> > * their pubactions are same.
> > ...
> > }
> >
> > entry->exprstate_valid = true;
> >
>
> This part of the code is changed in v68 which makes the current code
> more suitable as we don't need to deal with memory context in if part.
> I am not sure if it is good to add the else block here but I think
> that is just a matter of personal preference.
>

Sorry, my mistake - I quoted the v67 source instead of the v68 source.

There is no else needed now at all. My suggestion becomes. e.g.

if (has_filter)
{
// deal with mem ctx ...
// combine filters ...
}
entry->exprstate_valid = true;
return;

------
Kind Regards,
Peter Smith
Fujitsu Australia