25-1: Fix follower assertions on attach snapshot races

[snaury]

Changelog entry

Fixed a rare assertion (process crash) when followers attached to leaders with an inconsistent snapshot. Fixes #15042.

Changelog category

• Bugfix

Description for reviewers

Followers produced crashes in production periodically complaining about log reordering, with an error message indicating as if they tried to apply a duplicate redo log entry (which shouldn't have been possible). Turns out snapshots created within read-only transactions that used QueueScan (e.g. ReadTable and ScanQuery) persisted an incorrect Serial field (a monotonically increasing change number) that was equal to the next transaction. When follower attached at just the right time, it could bootstrap from such a snapshot, and discover the next commit has the same Serial, indicating a duplicate or reordered change.

Thankfully this didn't affect leaders, since they apply pre-snapshot and post-snapshot redo log entries together, and only use snapshot serial as a hint of previously compacted changes. So even though snapshot technically had an inconsistent value it was self-healing and couldn't produce any externally visible inconsistencies.

[github-actions]

⚪ 2025-02-26 14:23:41 UTC Pre-commit check linux-x86_64-release-asan for 006f160 has started.
⚪ 2025-02-26 14:23:56 UTC Artifacts will be uploaded here
⚪ 2025-02-26 14:26:56 UTC ya make is running...
🟡 2025-02-26 15:40:55 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Details

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
12213	12135	0	28	11	39

⚪ 2025-02-26 15:42:17 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-02-26 16:03:37 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Details

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
123 (only retried tests)	85	0	1	0	37

⚪ 2025-02-26 16:03:47 UTC ya make is running... (failed tests rerun, try 3)
🟢 2025-02-26 16:23:42 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
69 (only retried tests)	34	0	0	0	35

🟢 2025-02-26 16:23:49 UTC Build successful.
🟢 2025-02-26 16:24:18 UTC ydbd size 3.6 GiB changed* by +56.7 KiB, which is < 100.0 KiB vs stable-25-1: OK

ydbd size dash	stable-25-1: d408be7	merge: 006f160	diff	diff %
ydbd size	3 899 117 872 Bytes	3 899 175 952 Bytes	+56.7 KiB	+0.001%
ydbd stripped size	1 364 752 048 Bytes	1 364 773 232 Bytes	+20.7 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]

⚪ 2025-02-26 14:24:26 UTC Pre-commit check linux-x86_64-relwithdebinfo for 006f160 has started.
⚪ 2025-02-26 14:24:39 UTC Artifacts will be uploaded here
⚪ 2025-02-26 14:27:32 UTC ya make is running...
🟡 2025-02-26 15:33:08 UTC Some tests failed, follow the links below. Going to retry failed tests...

Details

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
26410	23812	0	2	2458	138

⚪ 2025-02-26 15:35:39 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-02-26 16:02:48 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
209 (only retried tests)	76	0	0	1	132

🟢 2025-02-26 16:03:00 UTC Build successful.
🟢 2025-02-26 16:03:19 UTC ydbd size 2.1 GiB changed* by +176 Bytes, which is < 100.0 KiB vs stable-25-1: OK

ydbd size dash	stable-25-1: 79eee97	merge: 006f160	diff	diff %
ydbd size	2 241 513 800 Bytes	2 241 513 976 Bytes	+176 Bytes	+0.000%
ydbd stripped size	474 785 208 Bytes	474 785 208 Bytes	0 Bytes	0.000%

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