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Azure SQL Blog
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Stop defragmenting and start living: introducing auto index compaction

Dimitri_Furman's avatar
Dimitri_Furman
Icon for Microsoft rankMicrosoft
Mar 18, 2026
Executive summary Automatic index compaction is a new built-in feature in the MSSQL database engine that compacts indexes in background and with minimal overhead. Now you can: Stop using sche...
Updated Mar 13, 2026
Version 1.0
azure sql
azure sql database
azure sql managed instance
m60freeman's avatar
m60freeman
Brass Contributor
Mar 23, 2026

It would be interesting to know how this compares with INDEX REBUILD, especially comparing the net performance impact on scans of the index on SSD vs. a magnetic drive. My hypothesis is that it would be reasonably close on SSD, but that INDEX REBUILD would have better results on magnetic drives, where random IO for a compacted index would be higher than for one rebuilt to be contiguous rather than only densely packed.