Something is wrong with how Oracle tracks I/O statistics in AWR – here's the reproducible anomaly, the evidence it's real and the investigation into what causes it.
Tag: Databases
Databases are the systems of record at the heart of the enterprise. They were designed for correctness, durability, and human-paced interaction – not for continuous, machine-driven access patterns.
As workloads evolve, the database remains the point of truth… but the assumptions around how it is accessed are starting to break.
Oracle AWR Reports: When Averages Lie
An ERP database showing intermittent slowdowns looked fine in AWR – because AWR averages hide latency spikes. Here's why averages mislead and what to look at instead.
Oracle, Parallelism and Direct Path Reads… on Flash
Oracle's parallel query engine behaves differently on flash than on spinning disk – direct path reads change the picture in ways that DBAs tuning for traditional storage won't expect.
Viewing ASM trace files in VIM: Which Way Do You Use?
A couple of people have asked me recently about a classic problem that most DBAs know: how to view ASM trace files in the VIM editor when the filenames start with a + character. To my surprise, there are actually quite a few different ways of doing it. Since it's come up, I thought I'd … Continue reading Viewing ASM trace files in VIM: Which Way Do You Use?
Oracle 12.1.0.2 ASM Filter Driver: Advanced Format Fail
The ASM Filter Driver introduced in Oracle 12.1.0.2 as a replacement for ASMLib has a critical flaw: it fails entirely with 4k native Advanced Format devices.
Oracle 12.1.0.2 ASM Filter Driver: First Impressions
Oracle's new ASM Filter Driver in 12.1.0.2 promises cleaner I/O filtering than ASMLib – here are the initial installation findings and what to watch out for with 4k devices.
New AWR Report Format: Oracle 11.2.0.4 and 12c
Oracle quietly changed the AWR report format in 11.2.0.4 and 12c – here's what moved, what's new and what DBAs relying on the old layout need to know.
New My Oracle Support note on Advanced Format (4k) storage
A new official Oracle support note on Advanced Format 4k storage – co-authored with Oracle ASM Development to replace the confusing and inconsistent guidance that existed before.
Oracle SLOB On Solaris
SLOB is primarily a Linux tool, but it runs on Solaris too – here's the configuration required and the key differences to watch out for when benchmarking Oracle I/O on Solaris.
More Problems with Oracle’s Support of 4k Devices
Bypassing ASM and using a filesystem doesn't escape Oracle's 4k compatibility issues – here's what breaks when you put Oracle on a 4k native device without ASM.
flashdba 