Tag: RHEL6
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XFS on RHEL6 for Oracle – solving issue with direct I/O
XFS on RHEL6 for Oracle – solving issue with direct I/O Recently we were refreshing our recovery system infrastructure, by moving automatic recoveries to new servers, with big bunch of disks directly connected to each of them. Everything went fine until we started to run recoveries – they were much slower than before, even though
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Oracle Optimizer Investigated with Flame Graphs
Oracle Optimizer Investigated with Flame Graphs Topic: This post is about investigating the Oracle Optimizer using stack sampling and flame graphs. We will see how the complexity of the Optimizer has increased over the years and in particular with the introduction of cost-based optimization and more recently with 12c adaptive optimization. Context and goal: Stack
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Flame Graphs for Oracle
Flame Graphs for Oracle Topic: This post is a hands-on introduction to using on-CPU Flame Graphs for investigating Oracle workloads. This technique is about collecting and visualizing sampled stack trace data to analyze and troubleshoot Oracle processes at the OS level (in particular applied to Linux). Motivations: The techniques and tools described here can be