storage: handle intents under ingested range key in CheckSSTConflicts

[itsbilal]

Previously, we were returning an obscure error around MVCCValueLenAndIsTombstone not being supported for interleaved intents if we encountered an intent in the engine. This change fixes that to return a more appropriate error.

This change also fixes a case where the engine iterator would unexpectedly land on a key < the sst iterator, violating an invariant in this function.

Fixes parts of #94141.

Release note: None

Epic: None

[cockroach-teamcity]

This change is 

[jbowens]

re: the backport-22.2.x label, do we actually need to backport this? MVCCValueLenAndIsTombstone does not exist on 22.2.

Reviewable status: complete! 1 of 0 LGTMs obtained

[erikgrinaker]

re: the backport-22.2.x label, do we actually need to backport this? MVCCValueLenAndIsTombstone does not exist on 22.2.

Not particularly important, since we don't ingest SSTs with range keys in production code. We were planning to start testing tenant replication with serverless on 22.2, which will ingest range keys, although I doubt these will use conflict checks. Would be nice to backport any correctness fixes if it's straightforward though. As for MVCCValueLenAndIsTombstone, that can be replaced by MVCCValue.IsTombstone().

[erikgrinaker]

Maybe I misunderstood what you meant. The problem isn't really that MVCCValueLenAndIsTombstone itself gives an unexpected error, it's that we don't handle intents correctly when ingesting range keys. The same bug exists in 22.2, and will lead to e.g. a committed-but-unresolved intent preventing the SST from being ingested.

[itsbilal]

TFTRs! I'll work on the backport shortly, as it'll have to be manual.

bors r=erikgrinaker

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from 745100d to blathers/backport-release-22.2-94395: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.2.x failed. See errors above.

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