battlefront 2 number of maps

First, control the number of maps in the hive task:1. Typically, the job produces one or more map tasks through the directory of input.The main determinants are: The total number of input files, the file size of input, the size of the file block set by the cluster (currently 128M, can be set dfs.block.size in hive; command to see, this parameter can not be custom

n times, there is another way is to split large files into small files, each small file processing time, will start a map. The former is usually worded as follows: Create TABLE Cajeep_test2 as Selecta.*,dummy_string dummy_string from TDL_EN_PP_NODE_STREAM_TMP2, Increase the size of the data file by increasing the dummy_string garbage field to achieve the function of dividing the file into multiple files; the latter requires a set mapred.reduce.tasks = 30;set hive.merge.mapredfiles= false; By us

1. Determining the number of maps Generally, a job generates one or more maps through the input file; MapThe main deciding factors of the number are: InputTotal number of files, inputFile Size and block set in the ClusterSize(You can run the set DFS. Block. SIZE command in h

Transfer from http://superlxw1234.iteye.com/blog/1582880First, control the number of maps in the hive task:1. Typically, the job produces one or more map tasks through the directory of input.The main determinants are: The total number of input files, the file size of input, the size of the file block set by the cluster (currently 128M, can be set dfs.block.size i

convenience, let's take a look at several terms: block_size: hdfs file block size. The default value is 64 mb. You can use the dfs parameter. block. size setting total_size: total size of the input file input_file_num: Number of input files (1) default number of maps. If no value is set, the default number of

Reprinted from: How to control the number of maps in HadoopHadoop provides a parameter mapred.map.tasks that sets the number of maps, which we can use to control the number of maps. However, setting the

first, control the number of maps in the Hive task:1. Typically, the job produces one or more map tasks through the directory of input.The main determinants are: The total number of input files, the file size of input, the size of the file block set by the cluster (currently 128M, can be set dfs.block.size in hive; command to see, this parameter can not be custom

1. Typically, the job produces one or more map tasks through the directory of input.The main determinants are: The total number of input files, the file size of input, the size of the file block set by the cluster (currently 128M, can be set dfs.block.size in hive; command to see, this parameter can not be customized modification);2. For example:A) Assuming that the input directory has 1 file A and a size o

The core source of control map number1 LongMinSize =Math.max (Getformatminsplitsize (), getminsplitsize (Job));2 3 //getformatminsplitsize Default Returns the minimum number of shards set by 1,getminsplitsize for the user, and the minimum number of shards set for the user if the user is set to greater than 14 LongMaxSize =getmaxsplitsize (Job);5 6 //getmaxsplit

Fileinputformat will split the input file into split before reading the data in the map phase. the number of split determines the number of maps. The main factors that affect the number of maps (split) are:1) The size of the file. When the Block (dfs.block.size) is 128m, if

Http://boylook.itpub.net/post/43144/531420 An error occurred while cleaning the Job of HiveCDH4.2.0 online. view the log and find a map oome: 650) this. width = 650; "src =" http://blog.itpub.net//resserver.php? BlogId=43144resource=hive1.png mode = medium "border =" 0 "alt =" resserver. php? BlogId = 43144 resource = hive "/> Check the log. The HQL table is joined by two tables. splits = 2 means that two maps