Re: doc: BRIN indexes and autosummarize - Mailing list pgsql-hackers

From Roberto Mello
Subject Re: doc: BRIN indexes and autosummarize
Date
Msg-id CAKz==b+as6QbpNXgzm2C2Q96UNBGP-K5bgs5fJH4V0Ln-K0fkA@mail.gmail.com
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In response to Re: doc: BRIN indexes and autosummarize  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
List pgsql-hackers
On Mon, Jul 4, 2022 at 9:20 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:

[Some of] these additions are wrong actually.  It says that autovacuum
will not summarize new entries; but it does.  If you just let the table
sit idle, any autovacuum run that cleans the table will also summarize
any ranges that need summarization.

What 'autosummarization=off' means is that the behavior to trigger an
immediate summarization of a range once it becomes full is not default.
This is very different.

Without having read through the code, I'll take your word for it. I simply went with what was written on this phrase of the docs:

"or by automatic summarization executed by autovacuum, as insertions occur. (This last trigger is disabled by default and can be enabled with the autosummarize parameter.)"

To me this did not indicate a third behavior, which is what you are describing, so I'm glad we're having this discussion to clarify it.

As for the new <para></para>s that you added, I'd say they're
stylistically wrong.  Each paragraph is supposed to be one fully
contained idea; what these tags do is split each idea across several
smaller paragraphs.  This is likely subjective though.

While I don't disagree with you, readability is more important. We have lots of places (such as that one on the docs) where we have a big blob of text, reducing readability, IMHO. In the source they are broken by new lines, but in the rendered HTML, which is what the vast majority of people read, they get rendered into a big blob-looking-thing.

> What would be the downside (if any) of having autosummarize=on by default?

I'm not aware of any.  Maybe we should turn it on by default.

 +1

Thanks for looking at this Alvaro.

Roberto
--
Cunchy Data -- passion for open source PostgreSQL

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