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From Vladimir Rodionov <vrodio...@carrieriq.com>
Subject RE: Extend ResultScanner API (and InternalScanner)
Date Fri, 23 Dec 2011 08:01:56 GMT
Yes, my aim is to reuse scanner for multiple scans. In some cases, "multiple"
can be in order of tens of thousands. The cost of creation of 10,000 scanners I suppose is
quite high.
This is mostly for the server-side (Coprocessors), We are replacing creating of a new scanner
with an 
absolute position operation which is, by default, much faster. 

As for use cases, 
some complex indexing schemes may involve multiple execution of a relatively short scan

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com

From: lars hofhansl [lhofhansl@yahoo.com]
Sent: Thursday, December 22, 2011 10:44 PM
To: dev@hbase.apache.org
Subject: Re: Extend ResultScanner API (and InternalScanner)

Your aim is reuse the same scanner for multiple scans?

seek(byte[] row) is equivalent to a new scan with startRow set to row.
seekToFirst() is equivalent to a new scan.

When would you use seekToLast() and prev()?

Would you envision to be a client side API, or just internal (for CoProcessors)?
Server side this should not be too hard to do. Client side it seems somewhat pointless as
it wouldn't reduce the number of roundtrips.
(But I might not understand fully what you want to achieve).

If you like to file a jira... Could you explain your usecases there?


-- Lars

 From: Vladimir Rodionov <vrodionov@carrieriq.com>
To: "dev@hbase.apache.org" <dev@hbase.apache.org>
Sent: Thursday, December 22, 2011 10:01 PM
Subject: Extend ResultScanner API (and InternalScanner)

This is suggestion and request at the same time:

It would be nice to have the following methods:

seek(byte[] row)



I am pretty sure its doable.

The reason is obvious: we can do much faster large number of short scans if we have this API.

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com

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