kv: respect exhausted key limit during ranged intent resolution #47492
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Fixes cockroachdb#47471. Fixes cockroachdb#40935. This commit fixes a long-standing bug where ranged intent resolution would not respect the MaxSpanRequestKeys set on a batch once the limit had already been exhausted by other requests in the same batch. Instead of treating the limit as exhausted, ranged intent resolution would consider the limit nonexistent (unbounded). This bug was triggering an assertion in DistSender. We became more likely to hit this issue in v20.1 because we started performing ranged intent resolution more often due to implicit SELECT FOR UPDATE. This commit fixes the bug in two ways: 1. it addresses the root cause, updating MVCCResolveWriteIntentRangeUsingIter to properly respect the limit placed on the request when it is exhauted. 2. it disables the assertion in DistSender when it detects that we are hitting this bug. This ensures that we don't hit the assertion in mixed version clusters (see cockroachdb#40935). By the time we're in DistSender, the damage is already done and has already potentially resulted in a large Raft entry. Maintaining the assertion doesn't do us any good. Release notes (bug fix): a bug that could could trigger an assertion with the text "received X results, limit was Y" has been fixed. The underlying bug was only performance related and could not cause user-visible correctness violations. Release justification: fixes a medium-priority bug in existing functionality. The bug could result in an assertion failure and a node crashing. Even though this was an old bug (present in many releases before v20.1), it became a lot easier to hit in v20.1 because we started performing ranged intent resolution more often due to implicit SELECT FOR UPDATE.
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andreimatei
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LGTM
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TFTR! I'm going to remove the new assertion from the backport because I don't want to risk having gotten than wrong at this stage in the game. bors r+ |
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…tSender This hack was added in cockroachdb#47492 to work around the bug that it was fixing in mixed-version clusters. Addresses a TODO.
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52364: keys: remove TODO on SystemConfigSpan r=nvanbenschoten a=nvanbenschoten This was addressed by #51379. 52365: kv: enable MaxSpanRequestKeys assertion for ResolveIntentRange in DistSender r=nvanbenschoten a=nvanbenschoten This hack was added in #47492 to work around the bug that it was fixing in mixed-version clusters. Addresses a TODO. Co-authored-by: Nathan VanBenschoten <[email protected]>
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Fixes #47471.
Fixes #40935.
This commit fixes a long-standing bug where ranged intent resolution would not respect the MaxSpanRequestKeys set on a batch once the limit had already been exhausted by other requests in the same batch. Instead of treating the limit as exhausted, ranged intent resolution would consider the limit nonexistent (unbounded). This bug was triggering an assertion in DistSender. We became more likely to hit this issue in v20.1 because we started performing ranged intent resolution more often due to implicit SELECT FOR UPDATE.
This commit fixes the bug in two ways:
Release notes (bug fix): a bug that could could trigger an assertion with the text "received X results, limit was Y" has been fixed. The underlying bug was only performance related and could not cause user-visible correctness violations.
Release justification: fixes a medium-priority bug in existing functionality. The bug could result in an assertion failure and a node crashing. Even though this was an old bug (present in many releases before v20.1), it became a lot easier to hit in v20.1 because we started performing ranged intent resolution more often due to implicit SELECT FOR UPDATE.