[
https://issues.apache.org/jira/browse/CASSANDRA-6944?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14087329#comment-14087329
]
graham sanderson edited comment on CASSANDRA-6944 at 8/6/14 6:42 AM:
---------------------------------------------------------------------
We just upgraded to 2.0.9 (from 2.0.5)
Lots more {{Memtable.java (line 470) setting live ratio to maximum of 64.0
instead of Infinity}}
Note quite sure when this is ever a useful warning? ... when you say:
{quote}
I say it's not a problem after CASSANDRA-6945
...
So as soon as some data starts flowing into the memtable, the ratio will be
recalculated. 64 will never stuck for long.
{quote}
I'm not sure if you are implying that empty memtables should be rare, or
what... but there are now LOTS of warnings, which IMHO should only be there if
it is undesirable/unexpected behavior
was (Author: graham sanderson):
We just upgraded to 2.0.9 (from 2.0.5)
Lots more {{Memtable.java (line 470) setting live ratio to maximum of 64.0
instead of Infinity}}
Note quite sure when this is ever a useful warning? ... when you say:
{quote}
I say it's not a problem after CASSANDRA-6945
...
So as soon as some data starts flowing into the memtable, the ratio will be
recalculated. 64 will never stuck for long.
{quote}
I'm not sure if you are implying that empty memtables should be rare, or
what... but there are now LOTS of warnings, which is either bad or not.
> liveRatio jumps to max when Memtable is empty
> ---------------------------------------------
>
> Key: CASSANDRA-6944
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6944
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: SUSE Linux Enterprise 11 (64-bit)
> Reporter: Erik Hansen
> Assignee: Aleksey Yeschenko
> Priority: Minor
> Labels: memtables
>
> liveRatio calculation on an empty memtable results in a value of Infinity
> since memtable.currentSize=0. Infinity then gets capped at the liveRatio max
> of 64.
> {noformat}
> WARN [MemoryMeter:1] 2014-03-19 09:26:59,483 Memtable.java (line 441) setting
> live ratio to maximum of 64.0 instead of Infinity
> INFO [MemoryMeter:1] 2014-03-19 09:26:59,485 Memtable.java (line 452)
> CFS(Keyspace='system', ColumnFamily='compactions_in_progress') liveRatio is
> 64.0 (just-counted was 64.0). calculation took 7ms for 0 cells
> {noformat}
> Jumping liveRatio to the max value based on an empty Memtable leads to more
> frequent flushing than may be necessary.
> CASSANDRA-4243 previously addressed this issue, but was resolved as fixed by
> CASSANDRA-3741. It does not appear this issue has been fixed as of 2.0.5
--
This message was sent by Atlassian JIRA
(v6.2#6252)
