问题
I want to get the interpretation of Map-Reduce logs after running a query on Hive-Tez ? What the lines after INFO: conveys ? Here I have attached a sample
INFO : Session is already open
INFO : Dag name: SELECT a.Model...)
INFO : Tez session was closed. Reopening...
INFO : Session re-established.
INFO :
INFO : Status: Running (Executing on YARN cluster with App id application_14708112341234_1234)
INFO : Map 1: -/- Map 3: -/- Map 4: -/- Map 7: -/- Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
INFO : Map 1: -/- Map 3: 0/118 Map 4: 0/118 Map 7: 0/1 Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
INFO : Map 1: 0/118 Map 3: 0/118 Map 4: 0/118 Map 7: 0/1 Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
INFO : Map 1: 0/118 Map 3: 0/118 Map 4: 0(+5)/118 Map 7: 0/1 Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
INFO : Map 1: 0/118 Map 3: 0(+5)/118 Map 4: 0(+7)/118 Map 7: 0(+1)/1 Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
INFO : Map 1: 0/118 Map 3: 0(+15)/118 Map 4: 0(+18)/118 Map 7: 0(+1)/1 Reducer 2: 0/15 Reducer 5: 0/26 Reducer 6: 0/13
回答1:
The log you posted is DAG execution log. The DAG consists of Map 1,Map 3,Map 4,Map 7 mappers vertices and reducers: Reducer 2,Reducer 5,Reducer 6
Map 1: -/- - this means that the vertex is not initialized, the number of mappers are not calculated yet.
Map 4: 0(+7)/118 - this means that totally there are 118 mappers, 7 of them are running in parallel, 0 completed yet, 118-7=111 are pending.
Reducer 2: 0/15 - this means that totally there are 15 reducers, 0 of them are running, 0 of them are completed (15 reducers pending).
Negative figures (there are no such in your example) = number of failed or killed mappers or reducers
Qubole has explanation about Tez log: https://docs.qubole.com/en/latest/user-guide/hive/using-hive-on-tez/hive-tez-tuning.html#understanding-log-pane
来源：https://stackoverflow.com/questions/39115712/map-reduce-logs-on-hive-tez