What does Forwarded Timestamp (iso=SERIALIZABLE) mean in AdminUI？
When two transactions attempt to touch the same data at more or less the same time in CockroachDB, generally one one will finish and the other will be re-run after it (often automatically, though sometimes it will require the client to retry), so that the two transactions actually happen one after the other, with the later one “forwarded” to a slightly later timestamp. The number you’re seeing is is essentially a measurement of contention – how many of your operations are contending with one another for access to the same data.
Does that help?
Thanks for your answer!
What is the “same data”? primary key contention?I think if is primary key contention ，it should not report this error。
Yep, “same data” would mean the same row (by primary key, at least by default) or the same values in secondary indexes, as well as a couple other internal cases.
It isn’t reporting it as an error per se, but rather just a measurement, so you can be aware of how much contention is affecting transactions, so that if you do see a slow-down or some other change in behavior, it might help you figure out what’s happening.