Re: Skip partition tuple routing with constant partition key

On Wed, Jun 16, 2021 at 4:27 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Mon, Jun 7, 2021 at 8:38 PM houzj.fnst@fujitsu.com
> <houzj.fnst@fujitsu.com> wrote:
> > The rough idea is to check the average batch number every 1000 rows.
> > If the average batch num is greater than 1, then we enable the cache check,
> > if not, disable cache check. This is similar to what 0d5f05cde0 did.
>
> Thanks for sharing the idea and writing a patch for it.
>
> I considered a simpler heuristic where we enable/disable caching of a
> given offset if it is found by the binary search algorithm at least N
> consecutive times.  But your idea to check the ratio of the number of
> tuples inserted over partition/bound offset changes every N tuples
> inserted may be more adaptive.
>
> Please find attached a revised version of your patch, where I tried to
> make it a bit easier to follow, hopefully.  While doing so, I realized
> that caching the bound offset across queries makes little sense now,
> so I decided to keep the changes confined to execPartition.c.  Do you
> have a counter-argument to that?

Attached a slightly revised version of that patch, with a commit
message this time.

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

+   int         n_tups_inserted;
+               part_index = get_cached_list_partition(pd, boundinfo, key,
+                   if (part_index < 0)
+                   {