VReplication: Support ignoring the source Keyspace on MoveTables cancel/complete

[mattlord]

Description

As noted in the issue you may have a MoveTables workflow running for a long time with the traffic switched so that all traffic is going to the target keyspace. Then at some point someone may delete/decommission the source keyspace as it's no longer needed — before having completed the workflow. If that happens then there's no way to complete the workflow and a number of manual steps would be needed to cleanup the Topo Server and MySQL data associated with the workflow. This PR adds a --ignore-source-keyspace flag to the MoveTables complete command in order to support the cleanup work in this scenario.

Manual tests:

cd examples/local
alias vtctldclient='command vtctldclient --server=localhost:15999' 

./101_initial_cluster.sh; ./201_customer_tablets.sh; ./202_move_tables.sh; ./203_switch_reads.sh; ./204_switch_writes.sh

for i in 100 101 102; do
        CELL=zone1 KEYSPACE=commerce TABLET_UID=$i ../common/scripts/vttablet-down.sh
done

vtctldclient --action_timeout 30s MoveTables --workflow commerce2customer --target-keyspace customer complete

vtctldclient MoveTables --workflow commerce2customer --target-keyspace customer complete --ignore-source-keyspace

./101_initial_cluster.sh; ./201_customer_tablets.sh; ./202_move_tables.sh; ./203_switch_reads.sh; ./204_switch_writes.sh

for i in 100 101 102; do
        CELL=zone1 KEYSPACE=commerce TABLET_UID=$i ../common/scripts/vttablet-down.sh
done

vtctldclient DeleteKeyspace commerce --recursive --force

vtctldclient --action_timeout 30s MoveTables --workflow commerce2customer --target-keyspace customer complete

vtctldclient MoveTables --workflow commerce2customer --target-keyspace customer complete --ignore-source-keyspace

Related Issue(s)

• Fixes: Feature Request: Add --force flag for MoveTables / Workflow completion #17517

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added: Update docs for https://github.com/vitessio/vitess/pull/17729 website#1938

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[codecov]

Codecov Report

Attention: Patch coverage is 66.14173% with 43 lines in your changes missing coverage. Please review.

Project coverage is 67.95%. Comparing base (b567098) to head (1d55e96).
Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/vtctl/workflow/server.go	74.41%	22 Missing ⚠️
...vtctldclient/command/vreplication/common/cancel.go	0.00%	7 Missing ⚠️
...ctldclient/command/vreplication/common/complete.go	0.00%	7 Missing ⚠️
...ctldclient/command/vreplication/workflow/delete.go	0.00%	7 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #17729   +/-   ##
=======================================
  Coverage   67.95%   67.95%           
=======================================
  Files        1586     1585    -1     
  Lines      255173   255236   +63     
=======================================
+ Hits       173398   173452   +54     
- Misses      81775    81784    +9     

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[rohit-nayak-ps]

We should probably pass req.IgnoreSourceKeyspace into dropSources() because dropSources() is doing a few of things that are missed in the path where req.IgnoreSourceKeyspace=true:

• validateWorkflowHasCompleted()
• dropTargetDeniedTables()

Also we are locking the keyspace in the path for req.IgnoreSourceKeyspace=false in dropSources() and adding dry run results as well.

[mattlord]

Good point. This was the first change I made in this work and after having done everything else I completely agree. Initially I was thinking dropSources was only source side and dropTargets was only target side but that proved to be mistaken. I've made this change. Thanks!