The default amount of lessen jobs per occupation. Commonly set to a prime near the number of offered hosts. Ignored when mapred.
No matter whether a MapJoin hashtable ought to deserialize values on desire. According to the quantity of values in the table the join will essentially touch, it may possibly help you save plenty of memory by not building objects for rows that are not desired. If all rows are required, naturally there is not any acquire.
If This can be established to correct, mapjoin optimization in Hive/Spark will use statistics from TableScan operators at the basis of operator tree, in lieu of mum or dad ReduceSink operators on the Join operator.
Sizing with the wait queue for async thread pool in HiveServer2. Just after hitting this Restrict, the async thread pool will reject new requests.
Besides the configuration Houses detailed in this segment, some HiveServer2 Qualities are listed in other sections:
Identify the volume of map process Employed in the adhere to up map sign up for job to get a skew join. It should be applied together with hive.skewjoin.mapjoin.min.break up to conduct a great grained Command.
Allows HiveServer2 to mail progress bar update information. This is often currently available provided that the execution motor is tez.
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Whether or not to employ a binary look for to locate the entries in an index table that match the filter, wherever possible.
Most range of bytes a useful reference script is allowed to emit to standard error (for each map-cut down process). This helps prevent runaway scripts from filling logs partitions to capability.
Some find queries could be converted to one FETCH endeavor, reducing latency. Presently the query really should be one sourced not obtaining any subquery and may not have any aggregations or distincts (which incur RS – ReduceSinkOperator, demanding a MapReduce task), lateral sights and joins.
This limits the number of partitions which can be requested through the Metastore for just a given table. A query will not be executed if it attempts to fetch a lot more partitions for each table in comparison to the Restrict configured.
A variety accustomed to proportion sampling. By modifying this variety, consumer will alter the subsets of knowledge sampled.
String made use of for a prefix when automobile More Info building column alias. By default the prefix label are going to be appended having a find out column posture selection to sort the column alias. Automobile generation would materialize if an mixture function is Employed in a decide on clause without having an express alias.