Hi Benedict,
So I had a look at the code, and as you say it looked pretty easy to recycle on
heap slabs… there is already RACE_ALLOCATED which keeps a strongly referenced
pool, however I was thinking in this case of just WeakReferences.
In terms of on heap slabs, it seemed to me that recycling
Hi Graham,
Unfortunately the problem is more difficult than you might think.
References to the buffers can persist in-flight to clients long after the
memtable is discarded, so you would be introducing a subtle corruption risk
for data returned to clients. Unfortunately the current implementation
Hi Benedict,
Ah, my mistake, I had assumed that since the memory backing the off heap
ByteBuffer Regions was freed on discard, that the Regions would be immediately
recyclable in the on heap case.
I guess I’ll just configure for one of the off-heap variants when 2.1 comes out…
Any idea of the
The current implementation is slower for a single memtable-only read
(dependent on workload, but similar ball park to on heap), but can store
substantially more per memtable under offheap_objects (again dependent on
workload, but as much as 8x in extreme cases) which means more queries are
answerab
Hi Benedict thanks once again for your explanations (hopefully these are my
last questions!)… I just read
https://issues.apache.org/jira/browse/CASSANDRA-6694 really quickly, so didn’t
follow all the discussions…. one thing to note that was argued in the middle
was about the cost of virtual met
