What caching value are you using on the scan?  If you aren't setting this, it's 
probably using the default - which is 1.  Which is slow.   
http://hbase.apache.org/book.html#d379e3504

Re:  "I would like to use HBase API, not MR job (because this cluster only has 
HDFS and HBase installed)."

For Very Large tables you want to start using an MR job for this.


-----Original Message-----
From: Wojciech Langiewicz [mailto:[email protected]] 
Sent: Sunday, May 01, 2011 9:44 AM
To: [email protected]
Subject: Row count without iterating over ResultScanner?

Hi,
I would like to know if there's a way to quickly count number of rows from scan 
result?
Right now I'm iterating over ResultScanner like this:
int count = 0;
for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
        ++count;
}
But with number of rows reaching millions this takes a while.
I tried to find something in documentation, but I didn't found anything.
I would like to use HBase API, not MR job (because this cluster only has HDFS 
and HBase installed).

Thanks for all help.

--
Wojciech Langiewicz

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