Re: [HACKERS] advanced partition matching algorithm for partition-wise join

On Wed, Oct 16, 2019 at 6:20 PM Etsuro Fujita <etsuro(dot)fujita(at)gmail(dot)com>
wrote:

> On Wed, Sep 25, 2019 at 12:59 AM Etsuro Fujita <etsuro(dot)fujita(at)gmail(dot)com>
> wrote:
> > I will continue to review the rest of the patch.
>
> I've been reviewing the rest of the patch. Here are my review comments:
>
[....]

> So I'd like to propose to introduce separate functions like
> process_outer_partition() and process_inner_partition() in the
> attached, instead of handle_missing_partition(). (I added a fast path
> to these functions that if both outer/inner sides have the default
> partitions, give up on merging partitions. Also, I modified the
> caller sites of proposed functions so that they call these if
> necessary.)
>

Agree -- process_outer_partition() & process_inner_partition() approach
looks
much cleaner than before.

Here are the few comments:

Note that LHS numbers are the line numbers in your previously posted
patch[1].

455 + if (inner_has_default ||
456 + jointype == JOIN_LEFT ||
457 + jointype == JOIN_ANTI ||
458 + jointype == JOIN_FULL)
459 + {
460 + if (!process_outer_partition(&outer_map,

512 + if (outer_has_default || jointype == JOIN_FULL)
513 + {
514 + if (!process_inner_partition(&outer_map,

How about adding these conditions to the else block of
process_outer_partition()
& process_inner_partition() function respectively so that these functions
can be
called unconditionally? Thoughts/Comments?
---

456 + jointype == JOIN_LEFT ||
457 + jointype == JOIN_ANTI ||
458 + jointype == JOIN_FULL)

Also, how about using IS_OUTER_JOIN() instead. But we need an assertion to
restrict JOIN_RIGHT or something.

For the convenience, I did both aforesaid changes in the attached delta
patch that
can be applied atop of your previously posted patch[1]. Kindly have a look
& share
your thoughts, thanks.
--

1273 + * *next_index is incremented when creating a new merged partition
associated
1274 + * with the given outer partition.
1275 + */

Correction: s/outer/inner
---

1338 + * In range partitioning, if the given outer partition is
already
1339 + * merged (eg, because we found an overlapping range earlier),
we know
1340 + * where it fits in the join result; nothing to do in that
case. Else
1341 + * create a new merged partition.

Correction: s/outer/inner.
---

1712 /*
1713 * If the NULL partition was missing from the inner side of
the join,

s/inner side/outer side
--

Regards,
Amul

1]
https://postgr.es/m/CAPmGK145V8DNCNQ2gQBgNE3QqoJGjsmK5WMwaA3FMirNM723KQ%40mail.gmail.com