| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>, suchithjn22(at)gmail(dot)com, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: The documentation for storage type 'plain' actually allows single byte header |
| Date: | 2023-10-22 01:59:04 |
| Message-ID: | ZTSB6JcPcpta3AGc@momjian.us |
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| Lists: | pgsql-docs pgsql-hackers |
On Sat, Oct 21, 2023 at 09:56:13PM -0400, Bruce Momjian wrote:
> I did some more research. It turns out that the source slot/planSlot is
> populating its pg_attribute information via makeTargetEntry() and it
> has no concept of a storage type.
>
> Digging further, I found that we cannot get rid of the the use of
> att->attstorage != TYPSTORAGE_PLAIN in macros ATT_IS_PACKABLE and
> VARLENA_ATT_IS_PACKABLE macros in src/backend/access/common/heaptuple.c
> because there are internal uses of fill_val() that can't handle packed
> varlena headers.
>
> I ended up with a doc patch that adds a C comment about this odd
> behavior and removes doc text about PLAIN storage not using packed
> headers.
Oops, patch attached.
--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com
Only you can decide what is important to you.
| Attachment | Content-Type | Size |
|---|---|---|
| varlena_short.diff | text/x-diff | 2.3 KB |
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