Re: Skip partition tuple routing with constant partition key

On Fri, Jun 4, 2021 at 6:05 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> On Fri, Jun 4, 2021 at 4:38 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> > On Thu, Jun 3, 2021 at 8:48 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> > > On Tue, Jun 1, 2021 at 5:43 PM houzj(dot)fnst(at)fujitsu(dot)com
> > > <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> > > > So, If we want to share the cached partition between statements, we seems cannot
> > > > use ExecPartitionCheck. Instead, I tried directly invoke the partition support
> > > > function(partsupfunc) to check If the cached info is correct. In this approach I
> > > > tried cache the *bound offset* in PartitionDescData, and we can use the bound offset
> > > > to get the bound datum from PartitionBoundInfoData and invoke the partsupfunc
> > > > to do the CHECK.
> > > >
> > > > Attach a POC patch about it. Just to share an idea about sharing cached partition info
> > > > between statements.
> > >
> > > I have not looked at your patch yet, but yeah that's what I would
> > > imagine doing it.
> >
> > Just read it and think it looks promising.
> >
> > On code, I wonder why not add the rechecking-cached-offset code
> > directly in get_partiiton_for_tuple(), instead of adding a whole new
> > function for that. Can you please check the attached revised version?

I should have clarified a bit more on why I think a new function
looked unnecessary to me. The thing about that function that bothered
me was that it appeared to duplicate a lot of code fragments of
get_partition_for_tuple(). That kind of duplication often leads to
bugs of omission later if something from either function needs to
change.

--
Amit Langote
EDB: http://www.enterprisedb.com