Create a sequence for prefixed vector indexes

[vitalif]

Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

Extracted from #25505, schemeshard part - sequence creation and value reset.

[github-actions]

⚪ 2025-09-30 07:55:31 UTC Pre-commit check linux-x86_64-release-asan for 639e0d1 has started.
⚪ 2025-09-30 07:55:45 UTC Artifacts will be uploaded here
⚫ 2025-09-30 07:56:53 UTC Check cancelled

[github-actions]

🟢 2025-09-30 07:55:34 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-09-30 07:58:21 UTC Pre-commit check linux-x86_64-relwithdebinfo for 5b05eed has started.
⚪ 2025-09-30 07:58:36 UTC Artifacts will be uploaded here
⚪ 2025-09-30 08:02:28 UTC ya make is running...
🟢 2025-09-30 09:51:01 UTC Tests successful.

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
40494	37727	0	0	2738	29

🟢 2025-09-30 09:51:10 UTC Build successful.
🟢 2025-09-30 09:51:24 UTC ydbd size 2.2 GiB changed* by +56.1 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fe9e8e0	merge: 5b05eed	diff	diff %
ydbd size	2 397 602 304 Bytes	2 397 659 784 Bytes	+56.1 KiB	+0.002%
ydbd stripped size	512 615 656 Bytes	512 627 752 Bytes	+11.8 KiB	+0.002%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-09-30 07:58:22 UTC Pre-commit check linux-x86_64-release-asan for 5b05eed has started.
⚪ 2025-09-30 07:58:37 UTC Artifacts will be uploaded here
⚪ 2025-09-30 08:02:40 UTC ya make is running...
🟡 2025-09-30 10:32:34 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
17554	16965	0	242	321	26

🟢 2025-09-30 10:32:40 UTC Build successful.
🟢 2025-09-30 10:33:04 UTC ydbd size 3.7 GiB changed* by +87.7 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fe9e8e0	merge: 5b05eed	diff	diff %
ydbd size	3 987 750 832 Bytes	3 987 840 680 Bytes	+87.7 KiB	+0.002%
ydbd stripped size	1 486 364 384 Bytes	1 486 396 032 Bytes	+30.9 KiB	+0.002%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[CyberROFL]

Что будет, если старая версия поднимется на данных новой, и в них будет записано это состояние?

[vitalif]

Достоверно не проверял... Но есть ощущение, что построение зависнет, т.к. нигде в case-ах, где проверяются состояния, нет default: Y_ENSURE(false), везде просто проход мимо. Правда, если бы и было, то катастрофы бы тоже не случилось, т.к. сейчас вся обработка построения индекса и загрузки начального состояния построения индекса обёрнута в try-catch и если ловится исключение, то операция построения индекса переходит в состояние Broken.

[CyberROFL]

Нужно обеспечить, чтобы описанная мной ситуация была безопасной: флагом, обработкой нового состояния в старых версиях и т.п.

[CyberROFL]

Шипаю в долг: #26046 (comment)

[vitalif]

Шипаю в долг: #26046 (comment)

Ок, спасибо. Но я уже пробую тест на этот кейс написать)