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Showing posts from April, 2012

Making sense out of BDB JE fast stats

Refer to EnvironmentStats ,for a run down of what all information gets dumped. StatsConfig has a setClear() method, which lets you get 'deltas' of values from last time instead of absolute values. I am going to cover fast stat metrics that relate to analysing issues in your "fast path"


Cache Usage & IO:


cacheTotalBytes/sharedCacheTotalBytes - gives you the how much each of your environments use out of your shared bdb cache. If you have a env, which has higher latency due to disk, then try tweaking the cache size.

nSequentialWriteBytes/nRandomWriteBytes & nSequentialReadBytes/nRandomReadBytes are very helpful in determining how much IO your app is actually throwing. Compare this to SAR/iostat output to see how much headroom you have. This is useful for SSDs as there is more headroom than spindle disks, where you run out of iops pretty soon and its all cache sizing after that.


Contention
nBINsFetchMiss/nBINsFetch  - gives you an estimate of the proportion of your…