stable-25-1-4: Optimized serialization in discovery cache cron job

[Gazizonoki]

Changelog entry

...

Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

SPI-158207

[github-actions]

⚪ 2025-09-30 14:51:13 UTC Pre-commit check linux-x86_64-relwithdebinfo for d11d802 has started.
⚪ 2025-09-30 14:51:34 UTC Artifacts will be uploaded here
⚪ 2025-09-30 14:55:12 UTC ya make is running...
🟡 2025-09-30 16:01:33 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
26957	25677	0	5	1223	52

⚪ 2025-09-30 16:03:56 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-09-30 16:25:31 UTC Tests successful.

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

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
99 (only retried tests)	55	0	0	0	44

🟢 2025-09-30 16:25:39 UTC Build successful.
🟢 2025-09-30 16:25:55 UTC ydbd size 2.2 GiB changed* by +944 Bytes, which is < 100.0 KiB vs stable-25-1-4: OK

ydbd size dash	stable-25-1-4: 45f347a	merge: d11d802	diff	diff %
ydbd size	2 323 680 384 Bytes	2 323 681 328 Bytes	+944 Bytes	+0.000%
ydbd stripped size	487 098 784 Bytes	487 099 040 Bytes	+256 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}

[github-actions]

🟢 2025-10-01 12:46:34 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-09-30 15:51:34 UTC Pre-commit check linux-x86_64-release-asan for d11d802 has started.
⚪ 2025-09-30 15:51:38 UTC Artifacts will be uploaded here
⚪ 2025-09-30 15:54:35 UTC ya make is running...
🟡 2025-09-30 17:00:22 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
12790	12609	0	39	105	37

⚪ 2025-09-30 17:01:32 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-09-30 17:24:31 UTC Tests successful.

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

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
230 (only retried tests)	193	0	0	2	35

🟢 2025-09-30 17:24:38 UTC Build successful.
🟢 2025-09-30 17:24:59 UTC ydbd size 3.8 GiB changed* by +2.9 KiB, which is < 100.0 KiB vs stable-25-1-4: OK

ydbd size dash	stable-25-1-4: 45f347a	merge: d11d802	diff	diff %
ydbd size	4 043 481 424 Bytes	4 043 484 400 Bytes	+2.9 KiB	+0.000%
ydbd stripped size	1 407 668 568 Bytes	1 407 669 656 Bytes	+1.1 KiB	+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}