Should We Defragment Indexes?
summary
Argues that defragmenting indexes can harm throughput on VM/cloud storage because forcing pages into sequential order concentrates them on a single capacity device and controller, reducing parallel I/O; leaving external fragmentation can let pages stay striped across multiple controllers and be faster. Explains rebuild vs reorg (rebuild creates a new index and can change fill factor; reorg only fixes order), notes internal fragmentation still hurts memory/optimizer, and recommends benchmark first and check actual storage topology.
AI-written summary · about
chapters (8)
- 0:00Introduction to maintenance
- 1:43Internal vs external fragmentation
- 3:32Reorgs vs rebuilds
- 5:26Impact on storage architecture
- 8:56The controller analogy
- 9:44Conclusion of main talk
- 10:47Q&A session
- 19:04Closing remarks
related talks
19mShould We Defragment Indexes?- 19mShould We Defragment Indexes?
53mIndexing Internals for Developers & DBAs- 53mIndexing Internals for Developers & DBAs
11mDatabase Evolution: Partitioning and Indexing
47mArchitecting for High Performance SQL Server on Virtual Machines
19mBest I/O is No I/O
14mRe-think Data Management Software Design Upon the Arrival of Storage Hardware with