< p>The following query works
Insert overwrite table tablename select a.id, b.name from a left join b on a.id = b.id limit 1; pre>But this is not the case
Insert overwrite table tablename select table1.id, table2.name from table1 left join table2 on table1.id = table2.id;< /pre>I increased the number of reducers, but it still doesn't work.
>Data skew, if you have possible data deviation 1 The reducer is doing all the work> Both sides copy the key-if There are many duplicate connection keys on both sides, the output may explode and the query may get stuck> one of your tables is small try to use map connection or SMB connection if possible, this is a huge performance gain, not a reduction side Connection>Go to the resource manager log to see the amount of data being accessed and written.
I use the left connection to insert records in Hive. When I set limit 1 query At the time, but for all record queries stayed at 99% reduction of work.
The following query works
Insert overwrite table tablename select a. id, b.name from a left join b on a.id = b.id limit 1;
But this is not the case
Insert overwrite table tablename select table1.id, table2.name from table1 left join table2 on table1.id = table2.id;< /pre>I increased the number of reducers, but it still doesn't work.
If your query is stuck at 99%, please check The following options-
>Data skew, if you have possible data deviation 1 The reducer is doing all the work> Both sides copy key-If there are many duplicate connection keys on both sides, the output may be Will explode, the query may get stuck> one of your tables is small try to use map connection or SMB connection if possible, this is a huge performance gain, not reduce side connection> go to explorer log and see what is being accessed And the amount of data written.