Yes, there are pauses around splits, and it's getting better with newer versions (0.20 is old). In 0.90 you can pre-split the tables when importing huge datasets http://hbase.apache.org/book/important_configurations.html#disable.splitting
You could try jstack'ing the region servers to figure where it's stuck, but unless you are using a 0.20 that's older than 0.20.6 the probability of getting a dead lock is extremely low. Please use this guide to debug HBase issues: http://hbase.apache.org/book/trouble.html EC2 might be another issue by itself. J-D On Thu, Apr 28, 2011 at 2:59 PM, Harold Lim <[email protected]> wrote: > Hi J-D, > > What I notice is that, when a region server is going to split the region > (create more regions), the write operations kind of paused, and then after a > few seconds, the write operations of my program will continue. > > However, there are cases where the write operations does not work anymore. I > go to the hbase shell and try to do some operations on the table and it does > not work too. Operations on other table still seem to work fine. > > > I'm using HBase 0.20.x (manually compiled). It's a 10 node cluster on EC2. No > special configurations. > > > Thanks, > Harold > > > > --- On Thu, 4/28/11, Jean-Daniel Cryans <[email protected]> wrote: > >> From: Jean-Daniel Cryans <[email protected]> >> Subject: Re: Write Operations on a Table Hangs >> To: [email protected] >> Date: Thursday, April 28, 2011, 4:55 PM >> That message only means that the >> region is being flushed before it's closed. >> >> When you say you can't write to it anymore, you mean at the >> moment of >> writing or if you let it alone for a few minutes and then >> come back >> would you be able to? >> >> It's not a behavior that I remember seeing, it might just >> be your >> description that's different. In any case, I've never seen >> disabling a >> table really doing any good. >> >> And which HBase version is that? What kind of cluster? Any >> special >> configuration? Anything about "blocking" in the logs? >> >> Thx, >> >> J-D >> >> On Thu, Apr 28, 2011 at 12:52 PM, Harold Lim <[email protected]> >> wrote: >> > Hi All, >> > >> > Sometimes when I try to write to a table (I have a >> program that writes lots of rows to an hbase table), it >> hangs and then I can't write to the table anymore. >> > When I look at a region server's log, I see the >> message >> > 13:49:59,945 DEBUG >> org.apache.hadoop.hbase.regionserver.HRegion: waiting for >> cache flush to complete for region usertable >> > >> > I try to disable/drop the table using the hbase shell >> but it keeps saying that the table is not disabled. >> > >> > Any idea what's causing this? >> > >> > Thanks, >> > Harold >> > >> > >> >
