Horton

Re: New Table Access Methods for Multi and Single Inserts

Luc Vlaming <luc@swarm64.com>

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From: Luc Vlaming <luc@swarm64.com>
To: Jeff Davis <pgsql@j-davis.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>, Paul Guo <guopa@vmware.com>
Date: 2021-01-06T07:00:55Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. libpq: Fix some issues in TAP tests for service files

  2. Multiple revisions to the GROUP BY reordering tests

  3. Explore alternative orderings of group-by pathkeys during optimization.

On 05-01-2021 22:28, Jeff Davis wrote:
> On Mon, 2021-01-04 at 08:59 +0100, Luc Vlaming wrote:
>> Reason I'm asking is that I quite liked the heap_insert_begin
>> parameter
>> is_multi, which could even be turned into a "expected_rowcount" of
>> the
>> amount of rows expected to be commited in the transaction (e.g.
>> single,
>> several, thousands/stream).
> 
> Do you mean "written by the statement" instead of "committed in the
> transaction"? It doesn't look like the TableInsertState state will
> survive across statement boundaries.
> 
> Though that is an important question to consider. If the premise is
> that a given custom AM may be much more efficient at bulk inserts than
> retail inserts (which is reasonable), then it makes sense to handle the
> case of a transaction with many single-tuple inserts. But keeping
> insert state across statement boundaries also raises a few potential
> problems.
> 
> Regards,
> 	Jeff Davis
> 
> 

I did actually mean until the end of the transaction. I know this is 
currently not possible with the current design but I think it would be 
cool to start going that way (even if slightly). Creating some more 
freedom on how a tableam optimizes inserts, when one syncs to disk, etc 
would be good imo. It would allow one to create e.g. a tableam that 
would not have as a high overhead when doing single statement inserts.

Kind regards,
Luc