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Avoid triggering N+1 on index page #38

Merged
merged 1 commit into from
Apr 8, 2024
Merged

Avoid triggering N+1 on index page #38

merged 1 commit into from
Apr 8, 2024

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luizkowalski
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I noticed a couple of N+1, namely:

  • recent_occurrence is being computed but never used
  • occurrences.size is not being computed, triggers N+1

To test it, I created a couple of exceptions locally
image

Queries before:

web        |   SolidErrors::Error Load (2.0ms)  SELECT "solid_errors".*, MAX("solid_errors_occurrences"."created_at") AS recent_occurrence FROM "solid_errors" INNER JOIN "solid_errors_occurrences" ON "solid_errors_occurrences"."error_id" = "solid_errors"."id" WHERE "solid_errors"."resolved_at" IS NULL GROUP BY "solid_errors"."id" ORDER BY "recent_occurrence" DESC
web        |   SolidErrors::Occurrence Count (0.6ms)  SELECT COUNT(*) FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 4]]
web        |   SolidErrors::Occurrence Maximum (0.2ms)  SELECT MAX("solid_errors_occurrences"."created_at") FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 4]]
web        |   SolidErrors::Occurrence Count (0.2ms)  SELECT COUNT(*) FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 3]]
web        |   SolidErrors::Occurrence Maximum (0.2ms)  SELECT MAX("solid_errors_occurrences"."created_at") FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 3]]
web        |   SolidErrors::Occurrence Count (0.3ms)  SELECT COUNT(*) FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 2]]
web        |   SolidErrors::Occurrence Maximum (0.2ms)  SELECT MAX("solid_errors_occurrences"."created_at") FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 2]]
web        |   SolidErrors::Occurrence Count (0.3ms)  SELECT COUNT(*) FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 1]]
web        |   SolidErrors::Occurrence Maximum (0.1ms)  SELECT MAX("solid_errors_occurrences"."created_at") FROM "solid_errors_occurrences" WHERE "solid_errors_occurrences"."error_id" = $1  [["error_id", 1]]

after:

web        |   SolidErrors::Error Load (0.5ms)  SELECT "solid_errors".*, MAX("solid_errors_occurrences"."created_at") AS recent_occurrence, COUNT("solid_errors_occurrences"."id") AS occurrences_count FROM "solid_errors" INNER JOIN "solid_errors_occurrences" ON "solid_errors_occurrences"."error_id" = "solid_errors"."id" WHERE "solid_errors"."resolved_at" IS NULL GROUP BY "solid_errors"."id" ORDER BY "recent_occurrence" DESC

fractaledmind
fractaledmind approved these changes Apr 8, 2024
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Great catch. And great PR. Thank you

@fractaledmind fractaledmind merged commit d89e870 into fractaledmind:main Apr 8, 2024
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fractaledmind added a commit that referenced this pull request Apr 9, 2024
@fractaledmind
After PR #38, ensure that last_seen_at is a DateTime object
bc44ff3
fractaledmind added a commit that referenced this pull request Apr 9, 2024
@fractaledmind
Merge pull request #41 from fractaledmind/fix-error-last-seen-at
4377de4 
After PR #38, ensure that last_seen_at is a DateTime object
@luizkowalski luizkowalski deleted the fix-unneeded-max branch April 23, 2024 19:01
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@fractaledmind fractaledmind fractaledmind approved these changes

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@luizkowalski @fractaledmind