Re: WAL usage calculation patch

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

To: Julien Rouhaud <rjuju123@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>

Cc: Justin Pryzby <pryzby@telsasoft.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, Kirill Bychik <kirill.bychik@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@gmail.com>

Date: 2020-04-23T06:46:50Z

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 →

Change the display of WAL usage statistics in Explain.
- 69bfaf2e1de4 13.0 landed
Cosmetic fixups for WAL usage work.
- ef08ca113fe3 13.0 landed
Allow parallel create index to accumulate buffer usage stats.
- 5c71362174eb 13.0 landed
- f179e9f01b65 11.8 landed
- 13823ad3b012 12.3 landed
Allow autovacuum to log WAL usage statistics.
- b7ce6de93b59 13.0 landed
Add the option to report WAL usage in EXPLAIN and auto_explain.
- 33e05f89c53e 13.0 landed
Allow pg_stat_statements to track WAL usage statistics.
- 6b466bf5f2be 13.0 landed
Add infrastructure to track WAL usage.
- df3b181499b4 13.0 landed
Include information on buffer usage during planning phase, in EXPLAIN output, take two.
- ce77abe63cfc 13.0 cited
Include information on buffer usage during planning phase, in EXPLAIN output.
- ed7a5095716e 13.0 cited
Allow parallel vacuum to accumulate buffer usage.
- 3a5e22138a8d 13.0 landed
Allow pg_stat_statements to track planning statistics.
- 17e03282241c 13.0 cited

On 2020-04-23 07:31, Julien Rouhaud wrote:
> I agree that full page writes can be used in this case, but I'm
> wondering if that can be misleading for some reader which might e.g.
> confuse with the full_page_writes GUC.  And as Justin pointed out, the
> documentation for now usually mentions "full page image(s)" in such
> cases.

ISTM that in the context of this patch, "full-page image" is correct.  A 
"full-page write" is what you do to a table or index page when you are 
recovering a full-page image.  The internal symbol for the WAL record is 
XLOG_FPI and xlogdesc.c prints it as "FPI".

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
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