[
https://issues.apache.org/jira/browse/HBASE-15787?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
ramkrishna.s.vasudevan updated HBASE-15787:
-------------------------------------------
Description:
With offheap MSLAB in place we may have to change the flush related heuristics
to work with offheap size configured rather than the java heap size.
Since we now have clear seperation of the memstore data size and memstore heap
size, for offheap memstore
-> Decide if the global.offheap.memstore.size is breached for blocking updates
and force flushes.
-> If the onheap global.memstore.size is breached (due to heap overhead) even
then block updates and force flushes.
-> The global.memstore.size.lower.limit is now by default 95% of the
global.memstore.size. So now we apply this 95% on the
global.offheap.memstore.size and also on global.memstore.size (as it was done
for onheap case).
-> We will have new FlushTypes introduces
{code}
ABOVE_ONHEAP_LOWER_MARK, /* happens due to lower mark breach of onheap
memstore settings
An offheap memstore can even breach the
onheap_lower_mark*/
ABOVE_ONHEAP_HIGHER_MARK,/* happens due to higher mark breach of onheap
memstore settings
An offheap memstore can even breach the
onheap_higher_mark*/
ABOVE_OFFHEAP_LOWER_MARK,/* happens due to lower mark breach of offheap
memstore settings*/
ABOVE_OFFHEAP_HIGHER_MARK;
{code}
-> regionServerAccounting does all the accounting.
-> HeapMemoryTuner is what is litte tricky here. First thing to note is that at
no point it will try to increase or decrease the global.offheap.memstore.size.
If there is a heap pressure then it will try to increase the memstore heap
limit.
In case of offheap memstore there is always a chance that the heap pressure
does not increase. In that case we could ideally decrease the heap limit for
memstore. The current logic of heapmemory tuner is such that things will
naturally settle down. But on discussion what we thought is let us include the
flush count that happens due to offheap pressure but give that a lesser
weightage and thus ensure that the initial decrease on memstore heap limit does
not happen. Currently that fraction is set as 0.5.
was:With offheap MSLAB in place we may have to change the flush related
heuristics to work with offheap size configured rather than the java heap size.
> Change the flush related heuristics to work with offheap size configured
> ------------------------------------------------------------------------
>
> Key: HBASE-15787
> URL: https://issues.apache.org/jira/browse/HBASE-15787
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Fix For: 2.0.0
>
> Attachments: HBASE-15787.patch
>
>
> With offheap MSLAB in place we may have to change the flush related
> heuristics to work with offheap size configured rather than the java heap
> size.
> Since we now have clear seperation of the memstore data size and memstore
> heap size, for offheap memstore
> -> Decide if the global.offheap.memstore.size is breached for blocking
> updates and force flushes.
> -> If the onheap global.memstore.size is breached (due to heap overhead) even
> then block updates and force flushes.
> -> The global.memstore.size.lower.limit is now by default 95% of the
> global.memstore.size. So now we apply this 95% on the
> global.offheap.memstore.size and also on global.memstore.size (as it was done
> for onheap case).
> -> We will have new FlushTypes introduces
> {code}
> ABOVE_ONHEAP_LOWER_MARK, /* happens due to lower mark breach of onheap
> memstore settings
> An offheap memstore can even breach the
> onheap_lower_mark*/
> ABOVE_ONHEAP_HIGHER_MARK,/* happens due to higher mark breach of onheap
> memstore settings
> An offheap memstore can even breach the
> onheap_higher_mark*/
> ABOVE_OFFHEAP_LOWER_MARK,/* happens due to lower mark breach of offheap
> memstore settings*/
> ABOVE_OFFHEAP_HIGHER_MARK;
> {code}
> -> regionServerAccounting does all the accounting.
> -> HeapMemoryTuner is what is litte tricky here. First thing to note is that
> at no point it will try to increase or decrease the
> global.offheap.memstore.size. If there is a heap pressure then it will try to
> increase the memstore heap limit.
> In case of offheap memstore there is always a chance that the heap pressure
> does not increase. In that case we could ideally decrease the heap limit for
> memstore. The current logic of heapmemory tuner is such that things will
> naturally settle down. But on discussion what we thought is let us include
> the flush count that happens due to offheap pressure but give that a lesser
> weightage and thus ensure that the initial decrease on memstore heap limit
> does not happen. Currently that fraction is set as 0.5.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
