Hi 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).
Vidhya 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 pretty > small (a few megabytes at most). > > It so turned out that all these files had rows whose TTL had expired. Now > when this region was scanned (which should yield a result of a null set), we > got Scanner timeouts and UnknownScannerExceptions. > > And when we tried scanning the region without the large column family, the > 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 output > 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 no > 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 >
