Mirror sync: защитить YDB от перезаписи новой версии устаревшим UPSERT

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Mirror sync ???????? ?????????? ?? updated_at / deleted_at, ?? ?????? ? YDB ??????????? ??????? ??????????? UPSERT.

???? ??? ??????? ???????? ???????????, ???????? ????????:

1. ?????? A ?????? remote snapshot;
2. ?????? B ?????????? ????? ????? ?????? ??????;
3. ?????? A ?????????? ???????????? ?????, ????? ?????? ??????;
4. ??????????? UPSERT ?????????????? ????? remote-?????? ??????????? ???????.

?????? ??? ?? ????????? ?????????: ???????? ???????????? ???????? ?? legacy-sync, ? mirror ???????????? ??? ????????? ??????/?????????? ??????????????.

??? ??????? ?????

• ??????? ?????? mirror-????? ????????: ????????? remote row ?????? ???? ???????? versionAt ????? ????????????.
• ?????? deleted_at ??? ????? ?????? tombstone.
• ????????? ????????? ? ?????? ???????? ?? ??????? YDB (?????????? ??? ???????? UPDATE/UPSERT).
• ???????? ?????????????? ???? ? ????? ?????????, ??? ?????????? push ???????? ????? ????? ??????.

???????? ??????????

??????? push ??????????? snapshot ?? ????? ???????????? ????? ????? live-?????? ??? tombstone ? YDB.