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https://issues.apache.org/jira/browse/HBASE-13320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14390036#comment-14390036
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ramkrishna.s.vasudevan commented on HBASE-13320:
------------------------------------------------
Thanks for checking this. Going through the complete calculation based on these
configs, with the default for 'hbase.bucketcache.size' being 65536 (64*1024),
then the capacity that we pass would be 64 * 1024*1024*1024 = 68719476736.
In the Bucketallocator assuming we have not configured any bucket sizes(going
by default), the maximum size would be (512 * 1024 + 1024). = 525312.
So
{code}
this.bucketCapacity = FEWEST_ITEMS_IN_BUCKET * bigItemSize;
{code}
would be 2101248 where the FEWEST_ITEMS_IN_BUCKET = 4.
For the buckets array
{code}
buckets = new Bucket[(int) (availableSpace / bucketCapacity)];
{code}
which is approx 32704.
When you configure it as 1, then the problem is this calculation leads to an
array which is less than 14. So any default value which is more than 14 should
be accounted for. If for any reason we have to keep the default ie. create
32704 sized bucket array only then I would suggest we leave the default as is,
but say that by default we would create buckets of size 64*1024*1024*1024.
Other wise we will just pass 64 in the hbase-default.xml so that we would alway
get 64*1024*1024 which would lead to an array size of 31. I think that would be
fine. But before changing it let us confirm on this size that has been
calculated.
Any thoughts on this [~zjushch],
[[email protected]],[~ndimiduk],[~anoop.hbase]?
> 'hbase.bucketcache.size' configuration value is not correct in
> hbase-default.xml
> ---------------------------------------------------------------------------------
>
> Key: HBASE-13320
> URL: https://issues.apache.org/jira/browse/HBASE-13320
> Project: HBase
> Issue Type: Bug
> Components: hbase
> Affects Versions: 2.0.0
> Reporter: Y. SREENIVASULU REDDY
> Assignee: Y. SREENIVASULU REDDY
> Fix For: 2.0.0
>
> Attachments: HBASE-13320.patch, HBASE-v2-13320.patch
>
>
> In hbase-default.xml file
> * 'hbase.bucketcache.size' is not correct
> We either specify it as a float or in MB's and the default value that is
> mentioned is never used
> {code}
> <property>
> <name>hbase.bucketcache.size</name>
> <value>65536</value>
> <source>hbase-default.xml</source>
> </property>
> {code}
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