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From: Jonathan Ellis <jbellis@gmail.com>
Date: Sun, 12 Sep 2010 15:47:09 -0500
Message-ID: <AANLkTikP4r-ydhWBKk2hzQ6QVCE1ZYx_DFt7RNveTugS@mail.gmail.com>
Subject: Re: Couple of cache related questions
To: user@cassandra.apache.org
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On Sun, Sep 12, 2010 at 2:56 PM, kannan chandrasekaran
<ckannanck@yahoo.com> wrote:
> 1) What determines the amount of memory used per schema ignoring the gene=
ral
> overhead to get cassandra up and running?=A0 Is it just the size of the c=
aches
> for the column Family + the memtable size ?

and the bloom filter and index samples from the sstable files.

> 2) Is the size of the cache configured ( in terms of absolute numbers or
> percentages), an upper bound on the amount of memory that can be allocate=
d
> and which grows as more data is filled up in the cache ?

no.  it's strictly the number of items you give it.  so you need to be
careful not to make it larger than you have room in the heap.

--=20
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com