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.
SQL Server
Microsoft SQL Server in practice: installation, Always On availability groups, backup and restore, performance tuning, security, PowerShell automation, SQL Server on Linux and upgrades.
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 of parallelism waits accumulated in only 11 days of uptime. Here are the questions that arise The waits themselves were not…
Green SQL Server DBA Tips #3 – The hidden cost of forgotten databases
How many times have I found, during a migration, that I also have to clean up the databases no more used?Why keep them for so long if we’re not going to use them? This is something we often see among our customers. If we assume that we carry out a migration project roughly every five years, this means we’re keeping…
SQL Server: msdb is in Suspect State
This Monday morning, we begin our SLA Support with a customer call.He cannot do a select on a table in his database… After creating the Ticket, I connect to the instance and see that the msdb system database is in a Suspect State: After taking a deep breath because I don’t see that every day, I begin my investigation by…
Green SQL Server DBA Tips #2 – When logs and history records cause your database to growth and crash
How often do I come across this sort of problem when visiting clients? Even more with our customers’ service desk (support) SLAs. We turn up on a Monday morning and there are alerts from the weekend saying [MSSQL] – Instance Dark_Vador-Data(F:): Disk space in GB on server Death_Star is critical Info: NOT OK – Free space: 20 MB out of…
SQL Server: Automatic index compaction in Azure (preview) – Part 2
Why does index fragmentation matter less than before ? Logical fragmentation was a problem on spinning disks: an ordered scan on a fragmented index broke the read-ahead into smaller I/Os and each jump cost a disk head movement. On SSD, NVMe and cloud storage, the penalty of non-sequential reads is marginal. And the “physical order” we used to restore so…
SQL Server: Automatic index compaction in Azure (preview) – Part 1
For years, we have all scheduled the same thing on our SQL Server environments: a nightly or weekly index maintenance job. We check the fragmentation level, we run a REORGANIZE between 5% and 30%, a REBUILD above 30% and we hope the job finishes before the business day starts. Microsoft recently released a new feature in public preview: automatic index…
Split, Sort, Collapse: how SQL Server survives an overlapping unique update
How SQL Server shifts a whole unique column by +1 without ever creating a duplicate using Split/Sort/Collapse.
Green SQL Server DBA Tips #1 – Are unnecessary indexes cluttering up your database?
This summer I start a series of blog posts on the ‘green SQL Server DBA’, as it’s a topic that continues to interest me and one that hasn’t been covered very much so far. I hope you’ll enjoy my tips, starting with this one on unused indexes. When discussing SQL Server performance, we often hear our performance tool say, ‘An…
Customer experience – Certificat SSL on an SQL Server Reporting Services
Recently, I had to renew an SSL certificate on an SQL Server Reporting Services (SSRS) server. The task seemed straightforward: replacing an expired certificate with a new one containing the same configuration. However, once the change had been made, HTTPS wasn’t working anywhere — neither via the usual DNS names nor even when accessing the server directly. Only HTTP remained…
When an idle transaction starves the worker pool (THREADPOOL)
How a forgotten transaction exhausted SQL Server’s worker pool, triggered THREADPOOL waits, and only DAC could fix it.
Zabbix Agent 2 service terminated unexpectedly on Windows server
Introductiom The Zabbix Agent 2 service on a Windows server was repeatedly becoming unresponsive and eventually crashing. The issue caused intermittent monitoring interruptions and required further investigation through Event Viewer messages and Zabbix Agent 2 logs to better understand why the service was no longer responding properly. While monitoring a Windows server with Zabbix Agent 2, we encountered repeated crashes…