Horton

Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)

Chao Li <li.evan.chao@gmail.com>

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From: Chao Li <li.evan.chao@gmail.com>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Kirill Reshke <reshkekirill@gmail.com>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Andrey Borodin <x4mmm@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>
Date: 2025-11-24T08:07:59Z
Lists: pgsql-hackers

Commits

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  1. Remove table_scan_analyze_next_tuple unneeded parameter OldestXmin

  2. Simplify visibility check in heap_page_would_be_all_visible()

  3. Eliminate use of cached VM value in lazy_scan_prune()

  4. Combine visibilitymap_set() cases in lazy_scan_prune()

  5. Fix const qualification in prune_freeze_setup()

  6. Simplify vacuum visibility assertion

  7. Split heap_page_prune_and_freeze() into helpers

  8. Assert that cutoffs are provided if freezing will be attempted

  9. Split PruneFreezeParams initializers to one field per line

  10. Refactor heap_page_prune_and_freeze() parameters into a struct

  11. Make heap_page_is_all_visible independent of LVRelState

  12. Inline TransactionIdFollows/Precedes[OrEquals]()

  13. Add helper for freeze determination to heap_page_prune_and_freeze

  14. Bump XLOG_PAGE_MAGIC after xl_heap_prune change

  15. Correct prune WAL record opcode name in comment

  16. Add error codes when vacuum discovers VM corruption

  17. Remove unused xl_heap_prune member, reason

  18. Remove unneeded VM pin from VM replay

  19. Add assert and log message to visibilitymap_set

  20. Add error codes to some corruption log messages


> On Nov 21, 2025, at 09:09, Chao Li <li.evan.chao@gmail.com> wrote:
> 
> I’d stop here today, and continue reviewing rest commits in next week.

I continue reviewing today.

0004 This a pure refactoring. It splits heap_page_prune_and_freeze to multiple small functions. LGTM, no comment.

0005 overall good, a few nit comments as below.

0006, 0007 look good, no comment.

5 - 0005 - heapam.h
```
+	/*
+	 *
+	 * vmbuffer is the buffer that must already contain contain the required
+	 * block of the visibility map if we are to update it. blk_known_av is the
```

Nit: 

* an unnecessary empty comment line.
* “contain contain” => “contain" 

6 - 0005 heapam_xlog.c
```
+		 * The critical integrity requirement here is that we must never end
+		 * up with with the visibility map bit set and the page-level
```

Nit: “with with” => “with”

I will continue reviewing 0008 and rest tomorrow.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/