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rewrite shuffleTablets to be clearer and more efficient #15716

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merged 2 commits into from Apr 30, 2024

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@demmer demmer commented Apr 15, 2024

Description

Implement a simple single-pass scan through the list of tablets that both randomly shuffles the set and pulls the same-cell hosts to the front of the list.

This is the same functionality as the old code, just with a simpler algorithm that only needs to loop once through the set of tablets so it's a marginally more efficient approach.

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@vitess-bot vitess-bot bot added NeedsBackportReason If backport labels have been applied to a PR, a justification is required NeedsDescriptionUpdate The description is not clear or comprehensive enough, and needs work NeedsIssue A linked issue is missing for this Pull Request NeedsWebsiteDocsUpdate What it says labels Apr 15, 2024
@github-actions github-actions bot added this to the v20.0.0 milestone Apr 15, 2024
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codecov bot commented Apr 15, 2024

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.43%. Comparing base (f118ba2) to head (d43907a).
Report is 35 commits behind head on main.

Additional details and impacted files
@@            Coverage Diff             @@
##             main   #15716      +/-   ##
==========================================
+ Coverage   68.40%   68.43%   +0.03%     
==========================================
  Files        1556     1558       +2     
  Lines      195121   195957     +836     
==========================================
+ Hits       133479   134111     +632     
- Misses      61642    61846     +204     

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@demmer demmer added Type: Internal Cleanup and removed NeedsDescriptionUpdate The description is not clear or comprehensive enough, and needs work NeedsWebsiteDocsUpdate What it says NeedsIssue A linked issue is missing for this Pull Request NeedsBackportReason If backport labels have been applied to a PR, a justification is required labels Apr 15, 2024
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deepthi commented Apr 16, 2024

@demmer you need to signoff the commit and force-push.

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demmer commented Apr 16, 2024

@demmer you need to signoff the commit and force-push.

Oh right. My Vitess contribution skills are rusty!

Implement a simple single-pass scan through the list of tablets that both
randomly shuffles the set and pulls the same-cell hosts to the front of the list.

Signed-off-by: Michael Demmer <mdemmer@slack-corp.com>
@demmer demmer force-pushed the tabletgateway-improve-shuffle branch from 32ad8ca to 9f1e23a Compare April 17, 2024 00:40
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demmer commented Apr 17, 2024

@deepthi Pushed again with the Signed-Off.

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Good to see you back :)

if sameCell < diffCell {
// fast forward the `sameCell` lookup to `diffCell + 1`, `diffCell` unchanged
sameCell = diffCell + 1
// Randomly shuffle the list of tablets, putting the same-cell hosts at the front
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nit: I'd always use tablet/tablets instead of host/hosts. Those are the Vitess terms.

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ok. edited.

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Love it!

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deepthi commented Apr 17, 2024

Let's give @demmer a chance to address feedback and then we can merge.

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deepthi commented Apr 25, 2024

@demmer DCO failed again. I guess the latest commit hasn't been signed off properly.

Signed-off-by: Michael Demmer <mdemmer@slack-corp.com>
@demmer demmer force-pushed the tabletgateway-improve-shuffle branch from 0bed5c6 to d43907a Compare April 26, 2024 03:17
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demmer commented Apr 26, 2024 via email

@deepthi deepthi merged commit c154771 into vitessio:main Apr 30, 2024
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3 participants