问题
We have insert query in which we are trying to insert data to partitioned table by reading data from non partitioned table.
Query -
insert into db1.fact_table PARTITION(part_col1, part_col2)
( col1,
col2,
col3,
col4,
col5,
col6,
.
.
.
.
.
.
.
col32
LOAD_DT,
part_col1,
Part_col2 )
select
col1,
col2,
col3,
col4,
col5,
col6,
.
.
.
.
.
.
.
col32,
part_col1,
Part_col2
from db1.main_table WHERE col1=0;
Table has 34 columns, number of records in main table depends on size of input file which we receive on daily basis. and the number of partitions (part_col1, part_col2) which we insert in each run might vary from 4000 to 5000
Some time this query fails with below issue.
2019-04-28 13:23:31,715 Stage-1 map = 95%, reduce = 0%, Cumulative CPU 177220.23 sec 2019-04-28 13:24:25,989 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 163577.82 sec MapReduce Total cumulative CPU time: 1 days 21 hours 26 minutes 17 seconds 820 msec Ended Job = job_1556004136988_155295 with errors Error during job, obtaining debugging information... Examining task ID: task_1556004136988_155295_m_000003 (and more) from job job_1556004136988_155295 Examining task ID: task_1556004136988_155295_m_000004 (and more) from job job_1556004136988_155295 Task with the most failures(4): ----- Task ID: task_1556004136988_155295_m_000000
----- Diagnostic Messages for this Task: Exception from container-launch. Container id: container_e81_1556004136988_155295_01_000015 Exit code: 255 Stack trace: ExitCodeException exitCode=255: at org.apache.hadoop.util.Shell.runCommand(Shell.java:563) at org.apache.hadoop.util.Shell.run(Shell.java:460) at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:748) at org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor.launchContainer(LinuxContainerExecutor.java:305) at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:356) at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:88) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Shell output: main : command provided 1 main : user is bldadmin main : requested yarn user is bldadmin Container exited with a non-zero exit code 255 FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask MapReduce Jobs Launched: Stage-Stage-1: Map: 10 Cumulative CPU: 163577.82 sec MAPRFS Read: 0 MAPRFS Write: 0 FAIL Total MapReduce CPU Time Spent: 1 days 21 hours 26 minutes 17 seconds 820 msec
Current hive properties.
Using Tez Engine -
set hive.execution.engine=tez;
set hive.tez.container.size=3072;
set hive.tez.java.opts=-Xmx1640m;
set hive.vectorized.execution.enabled=false;
set hive.vectorized.execution.reduce.enabled=false;
set hive.enforce.bucketing=true;
set hive.exec.parallel=true;
set hive.auto.convert.join=false;
set hive.enforce.bucketmapjoin=true;
set hive.optimize.bucketmapjoin.sortedmerge=true;
set hive.optimize.bucketmapjoin=true;
set hive.exec.tmp.maprfsvolume=false;
set hive.exec.dynamic.partition.mode=nonstrict;
set hive.exec.dynamic.partition=true;
set hive.stats.fetch.partition.stats=true;
set hive.support.concurrency=true;
set hive.exec.max.dynamic.partitions=999999999;
set hive.enforce.bucketing=true;
set hive.exec.dynamic.partition.mode=nonstrict;
set hive.txn.manager=org.apache.hadoop.hive.ql.lockmgr.DbTxnManager;
set hive.compactor.initiator.on=true;
Based on input from other teams we changed the engine to mr and propertied are -
set hive.execution.engine=mr;
set hive.auto.convert.join=false;
set mapreduce.map.memory.mb=16384;
set mapreduce.map.java.opts=-Xmx14745m;
set mapreduce.reduce.memory.mb=16384;
set mapreduce.reduce.java.opts=-Xmx14745m;
With these properties query completed with out any errors few times.
How can i debug these issue and are there any hive properties which we can set so that we don't get these issues in future.
回答1:
Add distribute by partition key. Each reducer will process only one partition, not every partition, this will result in less memory consumption, because reducer will create less files, keeping less buffers.
insert into db1.fact_table PARTITION(part_col1, part_col2)
select
col1,
...
col32,
part_col1,
Part_col2
from db1.main_table WHERE col1=0
distribute by part_col1, Part_col2; --add this
Use Predicate Push Down, it may help with filtering if source files are ORC:
SET hive.optimize.ppd=true;
SET hive.optimize.ppd.storage=true;
SET hive.optimize.index.filter=true;
Tune proper mapper and reducer parallelism: https://stackoverflow.com/a/48487306/2700344
Add distribute by random in addition to partition keys if your data is too big and the distribution by partition key is not even. This will help with skewed data:
distribute by part_col1, Part_col2, FLOOR(RAND()*100.0)%20;
Read also https://stackoverflow.com/a/55375261/2700344
来源：https://stackoverflow.com/questions/55919060/issue-in-hive-query-due-to-memory