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Date: Tue, 17 Aug 2010 10:55:27 -0700
Message-ID: <AANLkTinhJLv6CzUG1k8MrAgMwjbVLA7mf+V5bS_kXv3F@mail.gmail.com>
Subject: cache sizes using percentages
From: Artie Copeland <yeslinux.now@gmail.com>
To: Cassandra Users Mailing List <user@cassandra.apache.org>
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if i set a key cache size of 100% the way i understand how that works is:

- the cache is not write through, but read through
- a key gets added to the cache on the first read if not already available
- the size of the cache will always increase for ever item read.  so if you
have 100mil items your key cache will grow to 100mil

Here are my questions:

if that is the case then what happens if you only have enough mem to store
10mil items in your key cache?
do you lose the other 90% how is it determined what is removed?
will the server keep adding til it gets OOM?
if you add a row cache as well how does that affect your percentage?
if there a priority between the cache? or are they independant so both will
try to be satisfied which would result in an OOM?

thanx,
artie

-- 
http://yeslinux.org
http://yestech.org

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if i set a key cache size of 100% the way i understand how that works is:<d=
iv><br></div><div>- the cache is not write through, but read through</div><=
div>- a key gets added to the cache on the first read if not already availa=
ble</div>
<div>- the size of the cache will always increase for ever item read. =A0so=
 if you have 100mil items your key cache will grow to 100mil</div><div><br>=
</div><div>Here are my questions:</div><div><div><br></div><div>if that is =
the case then what happens if you only have enough mem to store 10mil items=
 in your key cache?=A0</div>
<div>do you lose the other 90% how is it determined what is removed?</div><=
div>will the server keep adding til it gets OOM?</div></div><div>if you add=
 a row cache as well how does that affect your percentage?=A0</div><div>if =
there a priority between the cache? or are they independant so both will tr=
y to be satisfied which would result in an OOM?</div>
<div><br></div><div>thanx,</div><div>artie</div><div><br>-- <br><a href=3D"=
http://yeslinux.org">http://yeslinux.org</a><br><a href=3D"http://yestech.o=
rg">http://yestech.org</a><br>
</div>

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