At my firm, I see these two commands used frequently, and I’d like to be aware of the differences, because their functionality seems the same to me: 1 2 They both copy the data from the directory on HDFS into the directory for the table on HIVE. Are there differences that one should be aware … Read more
These parameters are used to make decision on when to use Map Join against Common join in hive, which ultimately affects query performance at the end. Map join is used when one of the join tables is small enough to fit in the memory, so it is very fast. here’s the explanation of all parameters: hive.auto.convert.join When this parameter set … Read more
You need to modify your select: I am not sure to which column on your demo staging you want to perform partitioning or which column in demo corresponds to land. But whatever is the column it should be present as the last column in select say your demo table column name is id so your … Read more
From the language manual: Convert time string with given pattern to Unix time stamp (in seconds) The result of this function is in seconds. Your result changes with the milliseconds portion of the date, but the unix functions only support seconds. For example: SELECT unix_timestamp(’10-Jun-15 10.00.00 AM’, ‘dd-MMM-yy hh.mm.ss a’); 1433930400 SELECT from_unixtime(1433930400, ‘dd-MMM-yy hh.mm.ss … Read more
You can update a Hive partition by, for example: This command does not move the old data, nor does it delete the old data. It simply sets the partition to the new location. To drop a partition, you can do Hope it helps!