For #3, take a look at http://en.wikipedia.org/wiki/Network_Time_Protocol
On Sat, Jun 12, 2010 at 2:22 PM, Mark Laffoon <mlaff...@semanticresearch.com > wrote: > I'm not having a lot of success figuring out the pattern. I am most > definitely not seeing stack traces in any of the logs. I'm not seeing any > errors in my app logs, although I haven't scoured every log from every > hadoop/mapreduce/hbase agent in the system (I really need to centralize > those logs). > > However, I have an HBase question that might be related: how are > timestamps handled/generated? > > 1. I have multiple clients (map/reduce task executors) hitting an HBase > cluster with multiple region servers. Assuming the client code doesn't > explicitly set the timestamp, which box actually generates the timestamp > for a put? > > 2. If a timestamp for a put (either generated by the client or by whatever > box) is older than the most recent, and I have maxVersions set to 1, does > the put get ignored? > > 3. If I have an HBase cluster, and the times of the various machines > aren't in sync, am I just asking for trouble? What do most people do to > keep their machines in sync? > > Thanks, > Mark > > -----Original Message----- > From: saint....@gmail.com [mailto:saint....@gmail.com] On Behalf Of Stack > Sent: Saturday, June 12, 2010 9:59 AM > To: user@hbase.apache.org > Subject: Re: ICV concurrency problem (?) > > On Fri, Jun 11, 2010 at 4:26 PM, Mark Laffoon > <mlaff...@semanticresearch.com> wrote: > > The other thing I didn't mention: I ran the 80x120000 test a few more > > times. Sometimes it works, and sometimes it doesn't <sigh>. Could there > be > > an issue with data being moved around regions? > > > > So, when it doesn't work, can you figure difference? Are tasks > failing? Are there exceptions in the hbase/tasktracker logs? > > St.Ack >
