MR任务
set hive.exec.reducers.max=3
set hive.exec.dynamic.partition.mode = true; --使用动态分区时,设置为ture。 set hive.exec.dynamic.partition.mode = nonstrict; --动态分区模式,默认值:strict,表示必须指定一个分区为静态分区;nonstrict模式表示允许所有的分区字段都可以使用动态分区。一般需要设置为nonstrict。 set hive.exec.max.dynamic.partitions.pernode =10; --在每个执行MR的节点上,最多可以创建多少个动态分区,默认值:100。 set hive.exec.max.dynamic.partitions =1000; --在所有执行MR的节点上,最多一共可以创建多少个动态分区,默认值:1000。 set hive.exec.max.created.files = 100000; --整个MR Job中最多可以创建多少个HDFS文件,默认值:100000。 set hive.error.on.empty.partition = false; --当有空分区产生时,是否抛出异常,默认值:false。 Hive文件产生大量小文件的原因: 一是文件本身的原因:小文件多,以及文件的大小; 二是使用动态分区,可能会导致产生大量分区,从而产生很多小文件,也会导致产生很多Mapper; 三是Reduce数量较多,Hive SQL输出文件的数量和Reduce的个数是一样的。 小文件带来的影响: 文件的数量和大小决定Mapper任务的数量,小文件越多,Mapper任务越多,每一个Mapper都会启动一个JVM来运行,所以这些任务的初始化和执行会花费大量的资源,严重影响性能。 在NameNode中每个文件大约占150字节,小文件多,会严重影响NameNode性能。 解决小文件问题: 如果动态分区数量不可预测,最好不用。如果用,最好使用distributed by分区字段,这样会对字段进行一个hash操作,把相同的分区给同一个Reduce处理; 减少Reduce数量; 进行以一些参数调整。
Hdfs文件数
java
指定目录下的文件夹,文件,容量大小
[root@mz-hadoop-01 ~]# hdfs dfs -count /user/hive/warehouse/paascloud_tcm.db/dwd/dwd_t_record_detailed
568 7433 6065483664 /user/hive/warehouse/paascloud_tcm.db/dwd/dwd_t_record_detailed
[root@mz-hadoop-01 ~]# hdfs dfs -count -h /user/hive/warehouse/paascloud_tcm.db/dwd/dwd_t_record_detailed
568 7.3 K 5.6 G /user/hive/warehouse/paascloud_tcm.db/dwd/dwd_t_record_detailed
Hive文件数
java
SELECT tbl_id,SUM(PARAM_VALUE) AS file_cnts
FROM
(
SELECT * FROM PARTITIONS WHERE tbl_id='97387'
) a
LEFT JOIN (SELECT * FROM partition_params WHERE PARAM_KEY='numFiles' ) b
ON a.part_id=b.part_id
GROUP BY tbl_id
ORDER BY file_cnts DESC;
TBL_ID file_cnts
------ -----------
97387 2082
所有文件数
java
SELECT SUM(PARAM_VALUE) AS file_cnts
FROM
(
SELECT * FROM PARTITIONS
) a
LEFT JOIN (SELECT * FROM partition_params WHERE PARAM_KEY='numFiles' ) b
ON a.part_id=b.part_id
file_cnts
-----------
340323
表文件数topN
java
SELECT e.*,f.*
FROM
(
SELECT c.*,d.db_id,d.tbl_name
FROM
(
SELECT tbl_id,SUM(PARAM_VALUE) AS file_cnts
FROM
(
SELECT * FROM PARTITIONS
) a
LEFT JOIN (
SELECT * FROM partition_params WHERE PARAM_KEY='numFiles'
) b
ON a.part_id=b.part_id
GROUP BY tbl_id
ORDER BY file_cnts DESC
) c
LEFT JOIN (
SELECT * FROM tbls
) d
ON c.tbl_id=d.tbl_id
) e LEFT JOIN
(
SELECT db_id AS db_id2,`desc`,DB_LOCATION_URI,NAME as db_name,OWNER_NAME,OWNER_TYPE FROM dbs
)f ON e.db_id=f.DB_ID2
库文件数topN
java
select
db_id,db_name,DB_LOCATION_URI,sum(file_cnts) as file_cnts
from (
SELECT e.*,f.*
FROM
(
SELECT c.*,d.db_id,d.tbl_name
FROM
(
SELECT tbl_id,SUM(PARAM_VALUE) AS file_cnts
FROM
(
SELECT * FROM PARTITIONS
) a
LEFT JOIN (
SELECT * FROM partition_params WHERE PARAM_KEY='numFiles'
) b
ON a.part_id=b.part_id
GROUP BY tbl_id
ORDER BY file_cnts DESC
) c
LEFT JOIN (
SELECT * FROM tbls
) d
ON c.tbl_id=d.tbl_id
) e LEFT JOIN
(
SELECT db_id AS db_id2,`desc`,DB_LOCATION_URI,NAME as db_name,OWNER_NAME,OWNER_TYPE FROM dbs
)f ON e.db_id=f.DB_ID2
)g group by db_id,db_name,DB_LOCATION_URI order by file_cnts desc
小文件压缩任务
java
package com.mingzhi.common.universal
import com.mingzhi.common.interf.{IDate, MySaveMode}
import com.mingzhi.common.utils.{HiveUtil, SinkUtil, SparkUtils, TableUtils}
import org.apache.commons.lang3.StringUtils
import org.apache.spark.sql.{DataFrame, SparkSession}
import org.apache.spark.storage.StorageLevel
/**
* 处理只有一个分区dt的表
*/
object table_compress_process {
private var hive_dbs: String = "paascloud"
private var hive_tables: String = "dwd_order_info_abi"
private var dt: String = "2023-06-30"
private var dt1: String = "2023-06-30"
def main(args: Array[String]): Unit = {
System.setProperty("HADOOP_USER_NAME", "root")
val builder = SparkUtils.getBuilder
if (System.getProperties.getProperty("os.name").contains("Windows")) {
builder.master("local[*]")
} else {
hive_dbs = args(0)
hive_tables = args(1)
dt = args(2)
dt1 = args(3)
}
val spark: SparkSession = builder.appName("clean_process").getOrCreate()
HiveUtil.openDynamicPartition(spark)
spark.sql("set spark.sql.shuffle.partitions=1")
if ("all".equalsIgnoreCase(hive_dbs)) {
val builder = new StringBuilder()
val frame_db = spark.sql("show databases").select("databaseName")
frame_db.show(false)
frame_db.collect().foreach(db => {
builder.append(db.toString().replace("[", "").replace("]", ","))
})
println("dbs:" + builder.toString())
hive_dbs = builder.toString()
}
hive_dbs.split(",").foreach(db => {
if (StringUtils.isNotBlank(db)) {
if ("all".equalsIgnoreCase(hive_tables)) {
compress_all_table(spark, db)
} else {
hive_tables.split(",").foreach(t => {
compress_the_table(spark, db, t)
})
}
}
})
spark.stop()
}
private def compress_the_table(spark: SparkSession, hive_db: String, table: String): Unit = {
println("compress_the_table======>:" + hive_db + "." + table)
spark.sql(s"use $hive_db")
if (TableUtils.tableExists(spark, hive_db, table)) {
try {
new IDate {
override def onDate(dt: String): Unit = {
/**
* 建议:对需要checkpoint的RDD,先执行persist(StorageLevel.DISK_ONLY)
*/
val f1 = spark.sql(
s"""
|
|select * from $hive_db.$table where dt='$dt'
|""".stripMargin)
.persist(StorageLevel.MEMORY_ONLY)
val r_ck: (DataFrame, String) = SparkUtils.persistDataFrame(spark, f1)
val f2 = r_ck._1
println("f2 show===>")
f2.show(false)
val type_ = TableUtils.getCompressType(spark, hive_db, table)
if ("HiveFileFormat".equalsIgnoreCase(type_)) {
println("sink HiveFileFormat table:" + table)
SinkUtil.sink_to_hive_HiveFileFormat(spark, f2, hive_db, table, null)
} else {
//spark表
SinkUtil.sink_to_hive(dt
, spark
, f2
, hive_db
, table
, type_
, MySaveMode.OverWriteByDt
, 1)
}
spark.sql(s"drop table ${r_ck._2} ")
}
}.invoke(dt, dt1)
} catch {
case e: org.apache.spark.sql.AnalysisException => {
println("exception1:" + e)
}
case e: Exception => println("exception:" + e)
}
}
}
private def compress_all_table(spark: SparkSession, hive_db: String): Unit = {
spark.sql(s"use $hive_db")
val frame_table = spark.sql(s"show tables")
frame_table.show(100, false)
frame_table.printSchema()
frame_table
.filter(r => {
!r.getAs[Boolean]("isTemporary")
})
.select("tableName").collect().foreach(r => {
//r:[ads_order_topn]
val table = r.toString().replace("[", "").replace("]", "")
println("compress table:" + hive_db + "." + table)
if (TableUtils.tableExists(spark, hive_db, table)) {
try {
new IDate {
override def onDate(dt: String): Unit = {
val f1 = spark.sql(
s"""
|
|select * from $hive_db.$table where dt='$dt'
|""".stripMargin)
SinkUtil.sink_to_hive(dt, spark, f1, hive_db, table, "orc", MySaveMode.OverWriteByDt, 1)
}
}.invoke(dt, dt1)
} catch {
case e: org.apache.spark.sql.AnalysisException => {
println("exception1:" + e)
}
case e: Exception => println("exception:" + e)
}
}
})
}
}