final Scan scan = new Scan(); scan.setCaching(1); scan.addColumn(family); ResultScanner rs=table.getScanner(scan);
the speed is: getTableScanner 2.28 next 27s832.12ms next 0.99ms next 0.94ms next 0.82ms next 0.94ms next 0.88ms next 0.95ms next 0.94ms next 1.37ms next 0.90ms next 0.89ms next 0.90ms next 0.91ms next 0.86ms next 1.23ms next 0.87ms next 0.87ms next 0.83ms next 0.87ms next 0.90ms next 0.91ms next 1.73ms next 0.98ms next 0.89ms next 0.86ms next 0.92ms next 1.33ms next 0.87ms next 0.89ms next 0.82ms next 0.87ms next 0.84ms next 0.94ms next 0.96ms next 0.93ms next 0.79ms next 0.82ms next 0.84ms next 0.84ms next 0.87ms next 1.17ms next 0.80ms next 1.25ms next 1.08ms next 1.08ms next 1.95ms next 1.66ms .... getTableScanner 0.98ms next 16s258.33ms next 0.95ms next 1.10ms next 1.06ms next 0.90ms next 2.13ms next 2.31ms next 1.02ms next 1.38ms next 0.97ms next 0.90ms next 0.85ms next 2.03ms next 1.01ms next 1.35ms next 1.05ms next 1.06ms next 1.02ms next 1.28ms next 0.94ms next 1.35ms next 0.86ms next 0.86ms next 0.88ms next 0.83ms next 0.92ms next 0.92ms next 1.09ms next 0.91ms ... Why the first next is too slowly ? HBase-0.20.6 On Wed, Jan 26, 2011 at 2:09 AM, Jean-Daniel Cryans <[email protected]>wrote: > Caching is the number of rows that will be fetched per RPC, depending > on how big your rows are you might want to set it larger or smaller. > Try 10 then do some experiments. > > There's not that many more, speed of reading is always improved with > caching. Make sure your data can fit in the block cache and that it > stays there. > > J-D > > On Tue, Jan 25, 2011 at 2:35 AM, 陈加俊 <[email protected]> wrote: > > final Scan scan = new Scan(); > > scan.setCaching(scannerCaching); > > scan.addColumn(family); > > > > table.getScanner(scan); > > > > For improving the speed of scan . > > How to adjust the parameters ? Is there any more parameters or methods > that > > I don't know. > > > -- Thanks & Best regards jiajun
