Basically how I came to this question - this happened super rarely, and we narrowed it down to hotspotting. Map was timing out on three regions which were 4-5 times bigger then other regions for the same table, and region split fixed this.
However, was just thinking about if there are maybe some recommendations or something about this, as it's also super hard to reproduce again same situation to retest it. On Thu, Apr 30, 2015 at 3:56 PM Michael Segel <[email protected]> wrote: > There is no single ‘right’ value. > > As you pointed out… some of your Mapper.map() iterations are taking longer > than 60 seconds. > > The first thing is to determine why that happens. (It could be normal, or > it could be bad code on your developers part. We don’t know.) > > The other thing is that if you determine that your code is perfect and it > does what you want it to do… and its a major part of your use case… you > then increase your timeouts to 120 seconds. > > The reason why its a tough issue is that we don’t know what hardware you > are using. How many nodes… code quality.. etc … too many factors. > > > > On Apr 30, 2015, at 6:51 AM, Dejan Menges <[email protected]> > wrote: > > > > Hi, > > > > What's the best practice to calculate this value for your cluster, if > there > > is some? > > > > In some situations we saw that some maps are taking more than default 60 > > seconds which was failing specific map job (as if it failed once, it > failed > > also every other time by number of configured retries). > > > > I would like to tune RPC parameters a bit, but googling and looking into > > HBase Book doesn't tell me how to calculate right values, and what else > to > > take a look beside hbase.rpc.timeout. > > > > Thanks a lot, > > Dejan > >
