Louis Tochon

Azure SQL Database: does automatic index compaction fix the UUIDv7 density problem?

Does Azure SQL automatic index compaction fix UUIDv7 page density? Yes after a load, but with continuous inserts it needs a fill factor below 100.

SQL Server 2025: is optimized locking really working? Ask the Extended Events

How to check what SQL Server 2025 optimized locking really does with Extended Events: escalations, LAQ attempts and restarts.

Calling AI from SQL Server 2025 can lock everyone out of your on-prem instance

sp_invoke_external_rest_endpoint has no limit in SQL Server 2025: each waiting call holds a worker. Compared with Azure SQL.

Archiving 5 TB from Oracle into SQL Server: views, indexes and compression (part 2)

Translating 4,000 Oracle views, rebuilding indexes offline on Standard Edition, and compressing clustered index to save 1T.

Archiving 5 TB from Oracle into SQL Server: a migration logbook (part 1)

Loading 5 TB from Oracle into SQL Server with SSMA: type overflows, heaps, and the settings that took 788 rows/s to 42,170.

SQL Server: why can’t I read the full table in parallel???

Why SQL Server keeps a full SELECT * serial: I/O cost is never divided across threads. Forcing parallelism burned 3x the CPU.

SQL Server: Stop ordering index columns by selectivity

Column order does not affect equality seeks in SQL Server. Measured on 5M rows, then proven inside the B-tree pages.

Why UUIDv7 does not reduce fragmentation in SQL Server

UUIDv7 places its timestamp first, but SQL Server compares uniqueidentifier values starting from the last bytes. Measured on 25,000 inserts: no gain over NEWID().

Fixing ORA-00904 on Oracle hidden columns during SSMA data migration

SSMA fails with ORA-00904 on Oracle SET UNUSED columns. Fix it with a custom select aliasing NULL, no source DDL required.

SQL Server vs MongoDB: When the cloud is your adversary (Always Encrypted vs Queryable Encryption)

When the cloud admin is the threat: how SQL Server and MongoDB let you query encrypted data, and what each approach costs.