public inbox for [email protected]
help / color / mirror / Atom feedFrom: Drouvot, Bertrand <[email protected]>
To: Justin Pryzby <[email protected]>
To: [email protected]
Subject: Re: ALTER TABLE uses a bistate but not for toast tables
Date: Wed, 7 Sep 2022 10:48:39 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
Hi,
On 6/22/22 4:38 PM, Justin Pryzby wrote:
> ATRewriteTable() calls table_tuple_insert() with a bistate, to avoid clobbering
> and polluting the buffers.
>
> But heap_insert() then calls
> heap_prepare_insert() >
> heap_toast_insert_or_update >
> toast_tuple_externalize >
> toast_save_datum >
> heap_insert(toastrel, toasttup, mycid, options, NULL /* without bistate:( */);
Good catch!
> I came up with this patch.
+ /* Release pin after main table, before switching to write to
toast table */
+ if (bistate)
+ ReleaseBulkInsertStatePin(bistate);
I'm not sure we should release and reuse here the bistate of the main
table: it looks like that with the patch ReadBufferBI() on the main
relation wont have the desired block already pinned (then would need to
perform a read).
What do you think about creating earlier a new dedicated bistate for the
toast table?
+ if (bistate)
+ {
+ table_finish_bulk_insert(toastrel, options); // XXX
I think it's too early, as it looks to me that at this stage we may have
not finished the whole bulk insert yet.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services:https://aws.amazon.com
view thread (5+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: ALTER TABLE uses a bistate but not for toast tables
In-Reply-To: <[email protected]>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox