On Fri, Jan 22, 2016 at 2:22 PM, z11373 <z11...@outlook.com> wrote: > Another observation which I really want to know why. > > I see 1 tablet server consistently shows high number of waiting scans, i.e. > '16 (435)' or '14 (476)' on Running Scans column, while the other 19 tablet > servers all showing '0 (0)' or sometimes showing single digit number. The > thing I don't understand is what I've seen from the Monitor UI for a table > at one snapshot for example, and this is more or less consistent from time > to time (when the test clients are still running). > > Server | Query | Running Scans > ==================== > TServer1 | 24 | 0 (0) > TServer2 | 37 | 0 (0) > TServer3 | 40 | 0 (0) > TServer4 | 1 | 0 (0) > TServer5 | 0 | 0 (0) > TServer6 | 57 | 0 (0) > TServer7 | 5 | 0 (0) > TServer8 | 4 | 0 (0) > TServer9 | 7 | 0 (0) > TServer10 | 0 | 0 (0) > TServer11 | 56 | 0 (0) > TServer12 | 124 | 0 (0) > TServer13 | 25 | 0 (0) > TServer14 | 121 | 16 (435) > TServer15 | 36 | 0 (0) > TServer16 | 21 | 0 (0) > TServer17 | 3 | 0 (0) > TServer18 | 107 | 0 (0) > TServer19 | 21 | 0 (0) > TServer20 | 92 | 0 (0) > > I'd really appreciate if someone could explain what may have happened, or > can point me to the right direction for starting the investigation. For the > record, there are 50 test clients, each may create multiple scanners to > query different data from that table. >
One starting point is to see what tablets are on that tablet server. One way to do this a grep like the following in the accumulo shell (note this command is from memory so it may have mistakes) grep -t accumulo.metadata -c loc <TServer14 addr as it would appear in metadata table> In the output of this, rows will contain <table id>:<tablet end row>. Maybe the tablet end rows can give you a clue. You can narrow the grep by restricting the row range using the table id. grep -t accumulo.metadata -b <table id> -e <table id>~ -c loc <TServer14 addr as it would appear in metadata table> There is a command in the shell to get table ids. > Thanks, > Z > > > > -- > View this message in context: > http://apache-accumulo.1065345.n5.nabble.com/question-on-data-block-cache-tp15906p15934.html > Sent from the Developers mailing list archive at Nabble.com. >
