- DbDumper::dumpStep(): tables are dumped until the step's deadline in one
REPEATABLE READ transaction and resumed at the last primary key in the
next step; the running table checksum is carried over. A dump that fits
in one step is fully consistent, otherwise the snapshot records
dbConsistent=false. BackupService uses it, so the database phase no
longer needs one long request (hosted Nextcloud, web cron)
- restore inserts 100 rows per statement and leaves tables whose checksum
already matches the dump untouched
- spike C: 30-step dump gives the same checksums as the one-shot dump;
restore rewrote only the 3 damaged tables of 147; 300k-row table
restored in 14.6 s instead of 46 s
dillard
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