Message-ID: <d079c042180a698179384d6a7a3109cd8310e285.camel@j-davis.com>
Subject: Re: Introduce new multi insert Table AM and improve performance of
 various SQL commands with it for Heap AM
From: Jeff Davis <pgsql@j-davis.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL-development
 <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>, Dilip
 Kumar <dilipbalaut@gmail.com>, Luc Vlaming <luc@swarm64.com>, Justin Pryzby
 <pryzby@telsasoft.com>, Michael Paquier <michael@paquier.xyz>, Matthias van
 de Meent <boekewurm+postgres@gmail.com>, Alexander Korotkov
 <aekorotkov@gmail.com>
Date: Mon, 26 Aug 2024 14:18:21 -0700
In-Reply-To: <CALj2ACXnCvcYvaz4aDH_ezUBJanz_Boi8W=76fOwrxiwSnUFOQ@mail.gmail.com>
References: 
	<CALj2ACXdrOmB6Na9amHWZHKvRT3Z0nwTRsCwoMT-npOBtmXLXg@mail.gmail.com>
	 <20230603223824.o7iyochli2dwwi7k@alap3.anarazel.de>
	 <CALj2ACX5UMWVFdrRNUE0KDrg54WV1cumBXwcETXhrPc1ibKAQA@mail.gmail.com>
	 <CAAWbhmj5Pio3nOUakObzLGCSS9dwFfgsNVDhwTGzXNwZc00uCQ@mail.gmail.com>
	 <CALj2ACVHC=c6eC9SRxhcTUrnXvNDNkEBgedi2WkVJYRb=0sWYw@mail.gmail.com>
	 <CALj2ACVE2h=LnFnpr3rh+6SZzdwzW5EZOYG2Z0t=p28Fn75eag@mail.gmail.com>
	 <CALj2ACWT0Rz8oybWBm5W4CeS0DvFkwaw-pEvGArhDLyPbZnW_g@mail.gmail.com>
	 <CALj2ACWxO3HPtpYZb765LZk-uKVuAvZPO1HDeZ8=mzMgVPgaww@mail.gmail.com>
	 <CALj2ACXJA4QQ_6zAHez0Uy-9t-ebmpox2y1QBja+mF4QP+h8WQ@mail.gmail.com>
	 <CAD21AoD97mhzF8cqsd2v1jg9z8xfvAJrPx6Wvi+Ev0Hmu96LJA@mail.gmail.com>
	 <CALj2ACUcv5pZoB0=gRrz54M9+YT9JCmo6FYyo5WUS6wnS+em=A@mail.gmail.com>
	 <CALj2ACWm77YofBMs9x3Zmp3ctNAhcS4TvPVuXKdfwCr22FqOHg@mail.gmail.com>
	 <6be6f58815dc0844fbe058edf56b4e735a6efc1c.camel@j-davis.com>
	 <CALj2ACWqVzhxDuWNTWAH-LuADvsyX0r-wpwgeJ+Q1FnAKjY5Yw@mail.gmail.com>
	 <2280bf7241119bb88cbe0fe5eb36490cbd04c0c0.camel@j-davis.com>
	 <CALj2ACU70HZm+0QRJdkGA5RdJUo4zPYnV2hzkiV-wH5QS2PAEQ@mail.gmail.com>
	 <12f1a2d8dd3b6305c0354f1c701f44b7be5e54eb.camel@j-davis.com>
	 <CALj2ACVMV=gMROte2=0LBFnSCRvzL4D9WK6oQ9ZHr4Qj2S8xWA@mail.gmail.com>
	 <8633171cb034aafc260fdf37df04b6c779aa1e2f.camel@j-davis.com>
	 <CALj2ACX9vVYHYkX8e6w058EuAs8JL5EsnzadTxGhpiE_Ep_ByA@mail.gmail.com>
	 <f2540511eff777eca435e60b9129eaa43e2ad548.camel@j-davis.com>
	 <CALj2ACWTrx1zxWvq8Uj2rEwCsDgQHeJ53WdvzZUw3kW+_VPG6A@mail.gmail.com>
	 <CALj2ACUz5+_YNEa4ZY-XG960_oXefM50MjD71VgSCAVDkF3bzQ@mail.gmail.com>
	 <229c4f7219ed164088dadc935df21e1cf125e191.camel@j-davis.com>
	 <CALj2ACX90L5Mb5Vv=jsvhOdZ8BVsfpZf-CdCGhtm2N+bGUCSjg@mail.gmail.com>
	 <CALj2ACXnCvcYvaz4aDH_ezUBJanz_Boi8W=76fOwrxiwSnUFOQ@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.4-0ubuntu2 
MIME-Version: 1.0
Archived-At: <https://www.postgresql.org/message-id/d079c042180a698179384d6a7a3109cd8310e285.camel%40j-davis.com>
Precedence: bulk

On Mon, 2024-08-26 at 11:09 +0530, Bharath Rupireddy wrote:
> On Wed, Jun 5, 2024 at 12:42=E2=80=AFPM Bharath Rupireddy
> <bharath.rupireddyforpostgres@gmail.com> wrote:
> >=20
> > Please find the v22 patches with the above changes.
>=20
> Please find the v23 patches after rebasing 0005 and adapting 0004 for
> 9758174e2e.


Thank you.

0001 API design:

* Remove TableModifyState.modify_end_callback.

* This patch means that we will either remove or deprecate
TableAmRoutine.multi_insert and finish_bulk_insert. Are there any
strong opinions about maintaining support for multi-insert, or should
we just remove it outright and force any new AMs to implement the new
APIs to maintain COPY performance?

* Why do we need a separate "modify_flags" and "options"? Can't we just
combine them into TABLE_MODIFY_* flags?


Alexander, you had some work in this area as well, such b1484a3f19. I
believe 0001 covers this use case in a different way: rather than
giving complete responsibility to the AM to insert into the indexes,
the caller provides a callback and the AM is responsible for calling it
at the time the tuples are flushed. Is that right?

The design has been out for a while, so unless others have suggestions,
I'm considering the major design points mostly settled and I will move
forward with something like 0001 (pending implementation issues).

Note: I believe this API will extend naturally to updates and deletes,
as well.


0001 implementation issues:

* We need default implementations for AMs that don't implement the new
APIs, so that the AM will still function even if it only defines the
single-tuple APIs. If we need to make use of the AM's multi_insert
method (I'm not sure we do), then the default methods would need to
handle that as well. (I thought a previous version had these default
implementations -- is there a reason they were removed?)

* I am confused about how the heap implementation manages state and
resets it. mistate->mem_cxt is initialized to a new memory context in
heap_modify_begin, and then re-initialized to another new memory
context in heap_modify_buffer_insert. Then the mistate->mem_cxt is also
used as a temp context for executing heap_multi_insert, and it gets
reset before calling the flush callback, which still needs the slots.

* Why materialize the slot at copyfrom.c:1308 if the slot is going to
be copied anyway (which also materializes it; see
tts_virtual_copyslot()) at heapam.c:2710?

* After correcting the memory issues, can you get updated performance
numbers for COPY?


Regards,
	Jeff Davis