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From Maciej Miklas <mac.mik...@googlemail.com>
Subject Row Cache Heap Requirements (Cassandra 1.0)
Date Fri, 28 Oct 2011 11:21:03 GMT
Hi all,

I've tested row cache, and find out, that it requires large amount of Heap -
I would like to verify this theory.

This is my test key space:
{
     TestCF: {

        row_key_1: {
            { clientKey: "MyTestCluientKey" },
            { tokenSecret: "kd94hf93k423kf44" },
            { verifier: "hfdp7dh39dks9884" },
            { callbackUrl: "http%3A%2F%2Fprinter.test.com%2Fready" },
            { accountId: "234567876545"},
            { mytestResourceId: "ADB112"},
            { dataTimestamp: "1308903420400" },
            { dataType: "ACCESS_PERMANENT"}
        },
        row_key_2: {
            { clientKey: "MyTestCluientKey" },
            { tokenSecret: "qdqergvhetyhvetyh" },
            { verifier: "wtrgvebyjnrnuiucewrqxcc" },
            { callbackUrl: "http%3A%2F%2Fprinter.test.com%2Fready" },
            { accountId: "23456789746534"},
            { mytestResourceId: "DQERGCWRTHB"},
            { dataTimestamp: "130890342333200" },
            { dataType: "ACCESS_LIMITED"}
        },

...
        row_key_x: {
    ....
        },

    }
}

Each row in CF: TestCF contains 8 columns. Row cache is enabled, key cache
is disabled. Row hit rate 0.99 - this is read only test.

My test loads 1.500.000 rows into cache - and this allocates about 3.5GB
heap - this is about 2KB pro single row - this is a lot....

Is it possible, that single row (8 columns) can allocate about 2KB heap?


Thank you,
Maciej

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