How would you interpret the following innotop output?

I'm trying to optimize an application running a MySQL with the InnoDB storage engine.

When running innotop in the live environment I get the following output:

When   Load  QPS     Slow  QCacheHit  KCacheHit  BpsIn   BpsOut 
Now    0.00   87.80     0     41.21%    100.00%  11.51k  836.42k
Total  0.00  105.50   190     15.04%     99.34%  13.23k  692.85k

When, Load, QPS and Slow are self-explanatory.

But what about QCac开发者_开发知识库heHit, KCacheHit, BpsIn and BpsOut? In general, what are considered "okay" values for those, and when should I start worrying?

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Ratios are useless. Seriously. Just ignore them. http://www.mysqlperformanceblog.com/2010/02/28/why-you-should-ignore-mysqls-key-cache-hit-ratio/

Yeah, I'm the author of innotop. I put those features in so people would stop asking me to.

From the article:

Summary

Major points in this article:

• Counter ratios are meaningless as a performance analysis metric because they are a) ratios of b) counters.
  • You need to look at absolute magnitude, not ratios.
  • For performance analysis, you need to measure elapsed time, not just the number of times something happens.
• In the absence of timing information, and if you trust the cache’s creator and assume that misses are more expensive than hits, then you care about cache misses, not cache hits.
• A Key_read is not guaranteed to be a random physical I/O, but it might be. Gather Key_reads/Uptime over 10-second or 60-second intervals and compare the results to your IO system’s capabilities.
• MySQL doesn’t have good instrumentation for scientifically choosing a key_buffer_size setting, but there are many unscientific approaches that are better than ratio-based tuning.
• Counter ratios suck for everything, not just for MyISAM tuning.

I’ve had some heated arguments over these points, so I don’t expect the above to pass without controversy. But really, it’s time to stop with the bad advice about counter ratios. The sooner we do that, the sooner we can move on to better things.

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QCacheHit is the percentage of the time that the query cache is hit. KCacheHit is the percentage of the time that the innodb buffer pool is hit (similar to the key buffer). BpsIn is the number of bytes coming in to your server, BpsOut is the bytes out.

QCacheHit should be relatively high, if you're using the query cache. Your rates seem low. KCacheHit should also be relatively high, and you're in good shape.

BpsIn/Out don't really matter, unless you're trying to optimize the amount of data being sent/received by your server.