Anomaly in Cost Calculation of Anti Semi Join With Nullable Columns
The SQL Server optimizer cost calculation of Anti Semi Join over null columns may produce bad execution plans if max server memory is set high. Continue Reading
Author: Nenad Noveljic
Expect – Alternative to Supplying Password to Command Line
The Expect framework can be used as an alternative to passing passwords to the command line. Continue Reading
Solaris 11.3 Hangs Because of Kernel Object Manager
The blog post describes a hanging issue which occurs after upgrading to Solaris 11.3. The problem is caused by the new kernel memory allocation mechanism. Continue Reading
Comparing Latency on Emulex and QLogic HBA Driver
The blog post describes the implementation differences between Emulex and HBA drivers which are relevant for latency. Continue Reading
DTrace: Tracing Specific Kernel Threads
The blog post explains how to trace threads based on the first procedure on the stack. Continue Reading
ZFS ARC Resizing (user_reserve_hint_pct)
New kernel parameter user_reserve_hint_pct for limiting the size of ZFS ARC cache causes frequent shrinks which, in turn, gives rise to CPU cross-call storms. Continue Reading
Emulex HBA Driver Performance Analysis (3) – Measuring Overhead
The blog post describes how to measure elapsed time in the Emulex HBA driver. Continue Reading
Emulex HBA Driver Performance Analysis (2) – Packet Flow
The blog post describes how to explore the SCSI packet flow through different processing stages in the Emulex HBA driver. Continue Reading
Emulex HBA Driver Performance Analysis (1) – Measuring Latency
The blog post describes how to measure latency on Emulex HBA driver. Continue Reading
Simultaneous patching not possible with datapatch
Unfortunately… Since the datapatch utility has been introduced it is not longer possible to patch more databases at the same time. Consequently, if you try to patch two databases simultaneously one of them will fail. The process The (oversimplified) flow… Continue Reading