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Comment by TimothyFitz | Hacker News Reader

Agreed. Reading the digg article I'm interpreting their perf claim to mean "on a loaded server in our cluster, if we try to do this query on a cold cache it takes 1.5 seconds to complete", because this is exactly how I would measure the performance.

When I test the performance of a query, I query a live mysql node (or at least a live replicated standby) of some data that's not actively being used (to give a realistic "cold-cache" scenario, even though the caches aren't necessarily cold).

If digg used this method, it would completely account for performance discrepancy. Digg did not release a benchmark, and trying to treat their findings as a repeatable benchmark is wrong.

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>Digg did not release a benchmark, and trying to treat their findings as a repeatable benchmark is wrong.

Yet they released record counts, schema, and then performance numbers, and then used their results to demonstrate the failure of the RDBMS (which they led into by saying that it, as some given philosophy, optimizes writes at the cost of reads, hence their poor read performance).

Many of the comments in here are baffling. Digg specifically used the hammer of NoSQL to pound the nail of their database needs, replacing MySQL. They've made a big deal about this. So why the noise about "they're different, man?" And now the petty whines about benchmark methodology when Digg made concrete claims about RDBMS systems?

I think the parent author's main point is they used a defective RDBMS as a representative example of all.

MySQL does not do certain things well. However many mature RDBMS's have solved these problems and its worth pointing that out before you drop the entire class of tools for the next shiny tech.

Because many of us have had the experience of going into a new project where we thought all the existing engineers were idiots, miraculously being given enough latitude to do things our way, and then finding that there were good reasons for those idiotic decisions, and our proposed replacement completely falls down under real-world conditions.

Eventually, you learn not to criticize projects that you aren't actively in the trenches with. There's almost always some subtlety you're missing, and the existing team is too busy fixing it to correct your misconception. I bet the Digg team is looking at these comments (well, if they have time) and thinking to themselves, "We tried that a year ago, and it didn't work. If only they knew..."

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