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List:       cassandra-user
Subject:    Re: newbie question: how do I know the total number of rows of a cf?
From:       aaron morton <aaron () thelastpickle ! com>
Date:       2011-03-31 23:23:08
Message-ID: EDCCDB67-ADF6-4313-8928-EC6E85C961B8 () thelastpickle ! com
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It iterates over all the SSTables and disk and estimates the number of keys by \
looking at how big the index is. It does not count the actual keys. 

aaron


On 31 Mar 2011, at 17:46, Sheng Chen wrote:

> I just found an estmateKeys() method of the ColumnFamilyStoreMBean.
> Is there any indication about how it works?
> 
> Sheng
> 
> 2011/3/28 Sheng Chen <chensheng2010@gmail.com>
> Hi all,
> I want to know how many records I am holding in Cassandra, just like count(*) in \
> sql. What can I do ? Thank you.
> 
> Sheng
> 
> 
> 


[Attachment #3 (unknown)]

<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; \
-webkit-line-break: after-white-space; ">It iterates over all the SSTables and disk \
and estimates the number of keys by looking at how big the index is. It does not \
count the actual keys.&nbsp;<div><br></div><div>aaron<br><div><br></div><div><br><div><div>On \
31 Mar 2011, at 17:46, Sheng Chen wrote:</div><br \
class="Apple-interchange-newline"><blockquote type="cite">I just found an \
estmateKeys() method of the ColumnFamilyStoreMBean.<div>Is there any indication about \
how it works?</div><div><br></div><div>Sheng<br><br><div \
class="gmail_quote">2011/3/28 Sheng Chen <span dir="ltr">&lt;<a \
href="mailto:chensheng2010@gmail.com">chensheng2010@gmail.com</a>&gt;</span><br> \
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex;">Hi all,<div>I want to know how many records I am holding in \
Cassandra, just like count(*) in sql.</div><div>What can I do ? Thank you.</div> \
<div><br></div><font color="#888888"><div>Sheng</div><div><br></div><div><br></div> \
</font></blockquote></div><br></div> \
</blockquote></div><br></div></div></body></html>



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