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release-23.1: kvcoord: Fix error handling and retries in mux rangefeed client" (#102094)#102318

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miretskiy merged 2 commits intocockroachdb:release-23.1from
miretskiy:backport23.1-98980-102094
Apr 26, 2023
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release-23.1: kvcoord: Fix error handling and retries in mux rangefeed client" (#102094)#102318
miretskiy merged 2 commits intocockroachdb:release-23.1from
miretskiy:backport23.1-98980-102094

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@miretskiy miretskiy commented Apr 26, 2023

Backport:

Please see individual PRs for details.
Release Justification: bug fixes in a disabled-by default functionality; improved rangefeed observability.
/cc @cockroachdb/release

Yevgeniy Miretskiy added 2 commits April 26, 2023 08:28
kvcoord: Add metric to keep track of restarted ranges in rangefeed
7fb995e 
Add a `distsender.rangefeed.restart_ranges` metric to keep track
of the number of ranges restarted due to transient error.

Epic: CRDB-25044
Release note: None
kvcoord: Fix error handling and retries in mux rangefeed client
25cdc67 
Fix error handling and retries when restarting rangefeeds.
A big difference between regular rangefeed, and mux rangefeed,
is regular rangefeed has a dedicated go routine per range.
This go routine is responsible for running a rangefeed, handling
its errors, management of state pertaining to the RPC call
(transport, retry information, routing information, etc), and
restarting rangefeed with backoff as needed.

Mux rangefeed, on the other hand, is not "loop" based.  Prior
to this PR, mux rangefeed, when it encountered a transient error,
would loose a lot of the restart state mentioned above.  For example,
it would loose the transport information, so that the restart would
run against the same node as before, resulting, potentially, in
busy loops.  Those busy loops (where the RPC call is restarted
against the same node/replica that just experienced an error), would
tend to make test flaky since they would take longer time to converge
to the state expected by the tests (such as `TestDecommission`) test.

This PR fixes this loss of state pertaining to single range restart
by associating this state with the long lived `activeMuxRangeFeed` state.

Fixes cockroachdb#96630
Fixes cockroachdb#100783
Informs cockroachdb#99631
Informs cockroachdb#101614

Release note: None
@miretskiy miretskiy requested review from a team, erikgrinaker and pav-kv April 26, 2023 12:30
@miretskiy miretskiy requested a review from a team as a code owner April 26, 2023 12:30
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blathers-crl bot commented Apr 26, 2023

Thanks for opening a backport.

Please check the backport criteria before merging:

  • Patches should only be created for serious issues or test-only changes.
  • Patches should not break backwards-compatibility.
  • Patches should change as little code as possible.
  • Patches should not change on-disk formats or node communication protocols.
  • Patches should not add new functionality.
  • Patches must not add, edit, or otherwise modify cluster versions; or add version gates.
If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.
  • There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
  • The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
  • New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
  • The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

  • What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
  • Will this work in a cluster of mixed patch versions? Did we test that?
  • If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

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cockroach-teamcity commented Apr 26, 2023

This change is Reviewable

@miretskiy miretskiy merged commit a4efaed into cockroachdb:release-23.1 Apr 26, 2023
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@pav-kv pav-kv Awaiting requested review from pav-kv

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@erikgrinaker erikgrinaker erikgrinaker approved these changes

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