Vidhyashankar Venkatarama... 2011-04-13, 07:40
Ted Yu 2011-04-13, 08:44
Vidhyashankar Venkatarama... 2011-04-13, 14:44
Gary Helmling 2011-04-13, 16:15
Jean-Daniel Cryans 2011-04-13, 16:42
Gary Helmling 2011-04-13, 17:05
Jean-Daniel Cryans 2011-04-13, 17:18
Vidhyashankar Venkatarama... 2011-04-13, 17:03
Gary Helmling 2011-04-13, 17:14
Did you try setting scanner time range. It takes min and max timestamps, and
when instantiating the scanner at RS, a time based filtering is done to
include only selected store files. Have a look at StoreFile.shouldseek(Scan,
Sortedset<byte). I think it should improve the response time.
On Wed, Apr 13, 2011 at 8:44 AM, Vidhyashankar Venkataraman <
[EMAIL PROTECTED]> wrote:
> We had enabled scanner caching but I don't think it is the same issue
> because scanner.next in this case is blocking: the scanner is busy in the
> region server but hasn't returned anything yet since a row to be returned
> hasn't been found yet (all rows have expired but are still there since they
> havent been compacted yet).
> On 4/13/11 1:44 AM, "Ted Yu" <[EMAIL PROTECTED]> wrote:
> Have you read the following thread ?
> "ScannerTimeoutException when a scan enables caching, no exception when it
> doesn't"Did you enable caching ? If not, it is different issue.
> On Wed, Apr 13, 2011 at 12:40 AM, Vidhyashankar Venkataraman <
> [EMAIL PROTECTED]> wrote:
> > (This could be a known issue. Please let me know if it is).
> > We had a set of uncompacted store files in a region. One of the column
> > families had a store file of 5 Gigs. The other column families were
> > small (a few megabytes at most).
> > It so turned out that all these files had rows whose TTL had expired.
> > when this region was scanned (which should yield a result of a null set),
> > got Scanner timeouts and UnknownScannerExceptions.
> > And when we tried scanning the region without the large column family,
> > scanner returned back safely with no result.
> > So, I major compacted it and the scan started working correctly.
> > So it looks like timeouts happen if the scanner does not return any
> > for a specified time.
> > Which isn't exactly the correct thing to do, because it could be the case
> > that the scanner was indeed busy but it just so happened that there are
> > rows yet to return back to the client.
> > We can try increasing the scanner timeout, but this doesn't resolve the
> > underlying problem. Is this a know issue?
> > Thank you
> > Vidhya
Vidhyashankar Venkatarama... 2011-04-13, 17:47
Himanshu Vashishtha 2011-04-13, 18:23