SQL Server

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.

SQL Server 2025 CU5: max lock manager cache memory (%): what I could reproduce and what I could not

Cumulative Update 5 for SQL Server 2025 was released on May 20, 2026 (build 17.0.4045.5). Seven entries in the KB, mostly fixes. One of them is not a fix: it is a new server configuration option, max lock manager(…)

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.

When tempdb write latency points below SQL Server

During a recent performance review on a SQL Server 2019 instance (AlwaysOn Failover Cluster Instance, bare-metal), one number stood out. This post follows the investigation: from a latency figure in a DMV, down the I/O path to a(…)

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.

Wait stats and Sub-NUMA clustering 

During a healthcheck at a client’s site, we collected performance data from a SQL Server 2019 Enterprise instance hosting a BI / data warehouse workload. Two lines in the wait statistics report immediately caught the eye: hundreds of hours(…)