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HBase, mail # user - Scan with Filter


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RE: Scan with Filter
Jonathan Gray 2011-01-18, 18:49
The API shows one row per next() call but the number of rows fetched per RPC can be configured much higher with Scan.setCaching().

Filters are basically just server-side predicates that will dictate which rows/columns/values will be returned to the client.  This does not relate to the number of rows sent per RPC.  See http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/filter/package-summary.html for more information about filters.

JG

> -----Original Message-----
> From: Weishung Chung [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, January 18, 2011 8:31 AM
> To: [EMAIL PROTECTED]
> Subject: Scan with Filter
>
> I have some questions about the way Hbase returns results. When we use
> HTable getScanner(Scan), it looks like it only retrieves 1 row per next() call
> which is different from how jdbc returns the resultset. If I set the Filter on
> the Scan, could it return a set of rows in one connection call? It looks like the
> ClientScanner does not make use of the Filter. Only the Scan uses the Filter in
> the readFields method. Please correct me if i am wrong about this.
>
> Thank you so much.