Performance: Do not schedule smartstate dispatch unless it is needed #15067
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People who enable smart-state, but use it only rarely will benefit greatly. The users who use smart-state heavily wouldn't be burdened that much as the smart-state itself consumes heck a lot of resources. The smart-state job dispatch is not something that is run every freaking moment. It is usually run manually or schedule by some policy. My assumption is that most of the time JobProxyDispatcher#dispatch will result in no-op. We can tell by single query that's really quick. The query uses index on jobs table and checks just existence (ends quickly on success). Note that touching queue is expensive (observation of heavily loaded deployments) compared to touching jobs table. Real time Savings depend on server load and number of zones.
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Checked commit isimluk@1b10ea7 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0 |
gtanzillo
approved these changes
May 16, 2017
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The smart-state job
dispatchis not something that is needed every other moment. It is usually initiated manually or scheduled by some policy. Most of the time (for most appliances) JobProxyDispatcher#dispatch will result in no-op. We can tell (whether it is needed) by a single query that's really quick. The query uses index on jobs table and checks just existence (ends quickly on success).Note that touching queue is expensive (observation of heavily loaded deployments) compared to touching jobs table.
Real time Savings depend on server load and number of zones.
People who enable smart-state, but use it only rarely will benefit greatly. The users who use smart-state heavily wouldn't be burdened that much as the smart-state itself consumes heck a lot of resources.