~/talk

Should We Defragment Indexes?

on YouTube 19m
Talkat SQLBits 2023 · 2023-03-14..03-18· [databases]

speaker

name:Rob Mandeville
links:none on file

resources

video:https://youtu.be/5-sOvPjHs_o
slides:none on file

summary

Argues that external fragmentation can make defragmenting counterproductive: rebuilding or reordering pages often concentrates them onto a single capacity device or controller in a VM/hypervisor storage layout, reducing parallel I/O and hurting throughput; contrasts that with fixing internal fragmentation (rebuilds reduce page count and can help the optimizer). Uses simple card-demo and storage-layout reasoning rather than heavy tooling, recommends benchmarking index maintenance in each environment (Azure SQL DB/Managed Instance, VMs) and favors cautious, measured reorgs over blind rebuild schedules.

AI-written summary · about

chapters (8)

  1. 0:00Introduction to maintenance
  2. 1:43Internal vs external fragmentation
  3. 3:32Reorgs vs rebuilds
  4. 5:26Impact on storage architecture
  5. 8:56The controller analogy
  6. 9:44Conclusion of main talk
  7. 10:47Q&A session
  8. 19:04Closing remarks

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