From: | James Coleman <jtc331(at)gmail(dot)com> |
---|---|
To: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | [DOCS] HOT - correct claim about indexes not referencing old line pointers |
Date: | 2023-09-29 17:39:07 |
Message-ID: | CAAaqYe8=vU7ze=DkkAtne96MjTXHWrxBMG7YKN1T4wceBM1OmA@mail.gmail.com |
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Lists: | pgsql-hackers |
Hello,
While working on my talk for PGConf.NYC next week I came across this
bullet in the docs on heap only tuples:
> Old versions of updated rows can be completely removed during normal
> operation, including SELECTs, instead of requiring periodic vacuum
> operations. (This is possible because indexes do not reference their page
> item identifiers.)
But when a HOT update happens the entry in an (logically unchanged)
index still points to the original heap tid, and that line item is
updated with a pointer to the new line pointer in the same page.
Assuming I'm understanding this correctly, attached is a patch
correcting the description.
Thanks,
James Coleman
Attachment | Content-Type | Size |
---|---|---|
v1-0001-Correct-HOT-docs-to-account-for-LP_REDIRECT.patch | application/octet-stream | 1.3 KB |
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