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release-23.1: sql/schemachanger: address bugs with column families #100030

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merged 3 commits into from Mar 30, 2023
Merged

release-23.1: sql/schemachanger: address bugs with column families #100030

merged 3 commits into from Mar 30, 2023

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@blathers-crl blathers-crl bot commented Mar 30, 2023 •
edited by rafiss

Backport 3/3 commits from #99953 on behalf of @fqazi.

/cc @cockroachdb/release

This PR addresses the following bugs with column families:

  1. On master and 23.1 after the removal of oprules, we have scenarios where not implemented assertions can be hit for column families when rollbacks occur. These changes add a more concrete assertion that just ensures that the column family is cleaned up, and rules to ensure appropriate sequencing for removal.
  2. When UPDATE/INSERTs were executed concurrently while adding a new column family, we could end up writing to the old primary key with the new column family. In happy path cases where everything was successful, this didn't matter, but if a rollback occurred we would have values left in the old primary index that runtime couldn't handle.
  3. We had no way of validating DML with concurrent schema changes in cases with rollbacks, these modifications add tests and the framework required this case.

Release note (bug fix): Concurrent DML while adding
a new column with a new column family can lead to
corruption in the existing primary index. If a rollback
occurs the table may no longer be accessible.

Release justification: bug fix

@fqazi
sql/schemachangr: dropping column families ran into errors
65de860 
Previously, dropping column families was not implemented,
when we eliminated oprules, we replaced the ops with
NotImplementedForDrop, which wasn't sufficient for
dropped columns. The column families are cleaned up
when the column type itself is dropped, so we don't
really need to do much here. To address this, this
patch will add code to only assert that either the
table is being dropped or the column family has been
removed earlier.

Fixes: #99796
Release note: None
@fqazi
sql: avoid writing to column families that do not exist in the primar…
192299b 
…y index

Previously, if a new column family was added during an add
column and an update/insert occurred concurrently, we could
end up writing to this new column family in any primary index.
This was inadequate because if the primary index did not store
the column, then runtime will have trouble reading data from this
table, since after a rollback the added column / column family
will get cleaned up from the table descriptor. To address this,
this patch avoids writing any columns not stored within an index
descriptor.

Fixes: #99950

Release note (bug fix): Concurrent DML while adding
a new column with a new column family can lead to
corruption in the existing primary index. If a rollback
occurs the table may no longer be accessible.
@fqazi
sql/schemachanger: add DML injection tests for rollback scenarios
632fa5a 
Previously, our DML injection tests only covered happy paths
for schema changes. We recently ran into a bug where the old
primary index was corrupted after DML and left in a bad state
visible only after a rollback. To address this, this patch
adds tests for this specific scenario and adds the ability
to test rollbacks with DML injection.

Epic: none

Release note: None
@blathers-crl blathers-crl bot requested a review from a team as a code owner March 30, 2023 06:08
@blathers-crl blathers-crl bot force-pushed the blathers/backport-release-23.1-99953 branch from 192299b to 0ed96dd Compare March 30, 2023 06:08
@blathers-crl blathers-crl bot requested a review from a team March 30, 2023 06:08
@blathers-crl blathers-crl bot requested a review from a team as a code owner March 30, 2023 06:08
@blathers-crl blathers-crl bot force-pushed the blathers/backport-release-23.1-99953 branch from f8d60f5 to 632fa5a Compare March 30, 2023 06:08
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blathers-crl bot commented Mar 30, 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?

@blathers-crl blathers-crl bot added blathers-backport This is a backport that Blathers created automatically. O-robot Originated from a bot. labels Mar 30, 2023
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rafiss
rafiss approved these changes Mar 30, 2023
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can you put in the request in #release-backports ?

@fqazi fqazi merged commit 4661050 into release-23.1 Mar 30, 2023
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@fqazi fqazi deleted the blathers/backport-release-23.1-99953 branch March 30, 2023 21:23
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@rafiss rafiss rafiss approved these changes

@DrewKimball DrewKimball Awaiting requested review from DrewKimball DrewKimball was automatically assigned from cockroachdb/sql-queries

@ajwerner ajwerner Awaiting requested review from ajwerner

@cucaroach cucaroach Awaiting requested review from cucaroach

@fqazi fqazi Awaiting requested review from fqazi

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