Anyone who has been around Oracle performance over the years knows the grief that hard parsing SQL queries can cause on highly concurrent applications. The number one reason for hard parsing has been applications that don’t use bind variables. Without bind variables queries that would otherwise be shared get recompiled because their text is different and Oracle treats them as different queries. Oracle addressed this issue with a parameter called cursor_sharing. The parameter cursor_sharing has three values exact – the default similar – replace literals with bind variables, if a histogram keep literal in place force – replace literals with…
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See Brendan Gregg’s blog on how important and cool heatmaps can be for showing latency information and how average latency hides what is really going on: Now if we want to create heatmap graphics, how can we do it? Two popular web methods for displaying graphics are Highcharts and D3. Two colleges of mine whipped up some quick examples in both Highcharts and D3 to show latency heatmaps and those two examples are shown below. The data in the charts is random just for the purposes of showing examples of these graphics in actions. Highcharts Heatmap see code at http://jsfiddle.net/vladiweb/GNd3G/ D3 Heatmap…