Evicted block count stat is gathered in:
protected long evictBlock(CachedBlock block) {
map.remove(block.getCacheKey());
updateSizeMetrics(block, true);
elements.decrementAndGet();
stats.evicted();
In EvictionThread#run():
LruBlockCache cache = this.cache.get();
if(cache == null) break;
cache.evict();
where cache is declared:
private WeakReference<LruBlockCache> cache;
Looks like cache became null (due to heap pressure), leading to 0 evictions
that you saw.
Cheers
On Sat, Jan 26, 2013 at 7:05 PM, Varun Sharma <va...@pinterest.com> wrote:
> Hi,
>
> I am running hbase 0.94.3 and I am trying to understand the LRU cache stats
> here:
>
> LRU Stats: total=428.75 MB, free=4.05 GB, max=4.46 GB, blocks=35961,
> accesses=23808283, hits=23098837, hitRatio=97.02%,
> cachingAccesses=23135166, cachingHits=23066278,
> cachingHitsRatio=99.70%, *evictions=0,
> evicted=33211*
> *
> *
> I don't understanding why the number of evictions is 0 - which means that
> the number of eviction thread runs is 0, AFAIK. Also, I see that 30K blocks
> were evicted - how is that possible ? I have set the hfile evict on close
> to the default value - which is false - so blocks should not be evicted
> when hfiles are closed. Where are the evicted blocks coming from when the
> block is mostly empty and no eviction runs have occured.
>
> Thanks
> Varun
>
