在一次hive数据库执行命令 set ngmr.exec.mode=cluster时，想看一下 ngmr.exec.mode参数原先的值是什么，所以写一下本篇博文，讲一下怎么查看hive中的参数。

一、hive查看当前环境配置命令

• set ：可以查看所有参数
• set -v ：可得到所有环境变量。如果没有-v参数，只显示与hadoop不同的配置。
• set 具体参数： 返回具体参数对应的值

案例一：set 具体参数

# 返回mapreduce.map.memory.mb参数的值
set mapreduce.map.memory.mb;

案例二：set 查询所有变量

set;

案例三：set -v查询所有环境变量

hive> set -v;
silent=off
fs.s3n.impl=org.apache.hadoop.fs.s3native.NativeS3FileSystem
datanucleus.validateColumns=false
mapred.task.cache.levels=2
hadoop.tmp.dir=/home/hexianghui/datahadoop
hadoop.native.lib=true
map.sort.class=org.apache.hadoop.util.QuickSort
ipc.client.idlethreshold=4000
mapred.system.dir=${hadoop.tmp.dir}/mapred/system
hive.script.serde=org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
mapred.job.tracker.persist.jobstatus.hours=0
io.skip.checksum.errors=false
fs.default.name=hdfs://192.168.0.4:9000
mapred.child.tmp=./tmp
datanucleus.cache.level2=false
mapred.skip.reduce.max.skip.groups=0
mapred.jobtracker.instrumentation=org.apache.hadoop.mapred.JobTrackerMetricsInst
mapred.tasktracker.dns.nameserver=default
io.sort.factor=10
hive.metastore.rawstore.impl=org.apache.hadoop.hive.metastore.ObjectStore
hive.metastore.local=true
mapred.task.timeout=600000
mapred.max.tracker.failures=4
hadoop.rpc.socket.factory.class.default=org.apache.hadoop.net.StandardSocketFactory
fs.hdfs.impl=org.apache.hadoop.hdfs.DistributedFileSystem
mapred.queue.default.acl-administer-jobs=*
mapred.queue.default.acl-submit-job=*
mapred.skip.map.auto.incr.proc.count=true
io.mapfile.bloom.size=1048576
tasktracker.http.threads=40
mapred.job.shuffle.merge.percent=0.66
fs.ftp.impl=org.apache.hadoop.fs.ftp.FTPFileSystem
io.bytes.per.checksum=512
mapred.output.compress=false
hive.test.mode.prefix=test_
hive.test.mode=false
hive.exec.compress.intermediate=false
topology.node.switch.mapping.impl=org.apache.hadoop.net.ScriptBasedMapping
datanucleus.cache.level2.type=SOFT
mapred.reduce.slowstart.completed.maps=0.05
mapred.reduce.max.attempts=4
fs.ramfs.impl=org.apache.hadoop.fs.InMemoryFileSystem
javax.jdo.option.ConnectionUserName=APP
mapred.skip.map.max.skip.records=0
hive.merge.mapfiles=true
hive.merge.size.smallfiles.avgsize=16000000
hive.test.mode.samplefreq=32
hive.optimize.skewjoin=false
mapred.job.tracker.persist.jobstatus.dir=/jobtracker/jobsInfo
fs.s3.buffer.dir=${hadoop.tmp.dir}/s3
hive.map.aggr.hash.min.reduction=0.5
job.end.retry.attempts=0
fs.file.impl=org.apache.hadoop.fs.LocalFileSystem
mapred.local.dir.minspacestart=0
hive.exec.compress.output=false
mapred.output.compression.type=RECORD
hive.script.recordreader=org.apache.hadoop.hive.ql.exec.TextRecordReader
topology.script.number.args=100
io.mapfile.bloom.error.rate=0.005
hive.exec.parallel.thread.number=8
mapred.max.tracker.blacklists=4
mapred.task.profile.maps=0-2
mapred.userlog.retain.hours=24
datanucleus.storeManagerType=rdbms
mapred.job.tracker.persist.jobstatus.active=false
hive.script.operator.id.env.var=HIVE_SCRIPT_OPERATOR_ID
hadoop.security.authorization=false
local.cache.size=10737418240
mapred.min.split.size=0
mapred.map.tasks=2
mapred.child.java.opts=-Xmx200m
hive.skewjoin.mapjoin.min.split=33554432
hive.metastore.warehouse.dir=/user/hive/warehouse
mapred.job.queue.name=default
hive.mapjoin.bucket.cache.size=100
datanucleus.transactionIsolation=read-committed
ipc.server.listen.queue.size=128
mapred.inmem.merge.threshold=1000
job.end.retry.interval=30000
mapred.skip.attempts.to.start.skipping=2
fs.checkpoint.dir=${hadoop.tmp.dir}/dfs/namesecondary
mapred.reduce.tasks=-1
mapred.merge.recordsBeforeProgress=10000
mapred.userlog.limit.kb=0
hive.skewjoin.key=100000
javax.jdo.option.ConnectionDriverName=org.apache.derby.jdbc.EmbeddedDriver
webinterface.private.actions=false
mapred.job.shuffle.input.buffer.percent=0.70
io.sort.spill.percent=0.80
hive.udtf.auto.progress=false
hive.session.id=hexianghui_201002232043
mapred.map.tasks.speculative.execution=true
hadoop.util.hash.type=murmur
hive.exec.script.maxerrsize=100000
hive.optimize.groupby=true
mapred.map.max.attempts=4
hive.default.fileformat=TextFile
hive.exec.scratchdir=/tmp/hive-${user.name}
mapred.job.tracker.handler.count=10
hive.script.recordwriter=org.apache.hadoop.hive.ql.exec.TextRecordWriter
hive.join.emit.interval=1000
datanucleus.validateConstraints=false
mapred.tasktracker.expiry.interval=600000
mapred.jobtracker.maxtasks.per.job=-1
mapred.jobtracker.job.history.block.size=3145728
keep.failed.task.files=false
ipc.client.tcpnodelay=false
mapred.task.profile.reduces=0-2
mapred.output.compression.codec=org.apache.hadoop.io.compress.DefaultCodec
io.map.index.skip=0
ipc.server.tcpnodelay=false
hive.join.cache.size=25000
datanucleus.autoStartMechanismMode=checked
hive.input.format=org.apache.hadoop.hive.ql.io.HiveInputFormat
hadoop.logfile.size=10000000
mapred.reduce.tasks.speculative.execution=true
hive.skewjoin.mapjoin.map.tasks=10000
hive.hwi.listen.port=9999
fs.checkpoint.period=3600
mapred.job.reuse.jvm.num.tasks=1
mapred.jobtracker.completeuserjobs.maximum=100
hive.groupby.mapaggr.checkinterval=100000
fs.s3.maxRetries=4
javax.jdo.option.ConnectionURL=jdbc:derby:;databaseName=metastore_db;create=true
hive.mapred.mode=nonstrict
hive.groupby.skewindata=false
hive.exec.parallel=false
mapred.local.dir=${hadoop.tmp.dir}/mapred/local
fs.hftp.impl=org.apache.hadoop.hdfs.HftpFileSystem
fs.s3.sleepTimeSeconds=10
fs.trash.interval=0
mapred.submit.replication=10
hive.merge.size.per.task=256000000
fs.har.impl=org.apache.hadoop.fs.HarFileSystem
mapred.map.output.compression.codec=org.apache.hadoop.io.compress.DefaultCodec
hive.exec.reducers.max=999
mapred.tasktracker.dns.interface=default
mapred.job.tracker=192.168.0.4:9001
io.seqfile.sorter.recordlimit=1000000
hive.optimize.ppd=true
mapred.line.input.format.linespermap=1
mapred.jobtracker.taskScheduler=org.apache.hadoop.mapred.JobQueueTaskScheduler
mapred.tasktracker.instrumentation=org.apache.hadoop.mapred.TaskTrackerMetricsInst
hive.mapjoin.cache.numrows=25000
hive.merge.mapredfiles=false
hive.metastore.connect.retries=5
hive.fileformat.check=true
mapred.tasktracker.procfsbasedprocesstree.sleeptime-before-sigkill=5000
javax.jdo.option.DetachAllOnCommit=true
mapred.local.dir.minspacekill=0
hive.optimize.pruner=true
javax.jdo.option.ConnectionPassword=mine
hive.hwi.listen.host=0.0.0.0
io.sort.record.percent=0.05
hive.map.aggr.hash.percentmemory=0.5
fs.kfs.impl=org.apache.hadoop.fs.kfs.KosmosFileSystem
mapred.temp.dir=${hadoop.tmp.dir}/mapred/temp
mapred.tasktracker.reduce.tasks.maximum=2
javax.jdo.PersistenceManagerFactoryClass=org.datanucleus.jdo.JDOPersistenceManagerFactory
hive.mapred.local.mem=0
fs.checkpoint.edits.dir=${fs.checkpoint.dir}
mapred.job.reduce.input.buffer.percent=0.0
datanucleus.validateTables=false
mapred.tasktracker.indexcache.mb=10
hadoop.logfile.count=10
mapred.skip.reduce.auto.incr.proc.count=truehive.script.auto.progress=false
io.seqfile.compress.blocksize=1000000
fs.s3.block.size=67108864
mapred.tasktracker.taskmemorymanager.monitoring-interval=5000
datanucleus.autoCreateSchema=true
mapred.acls.enabled=false
mapred.queue.names=default
fs.hsftp.impl=org.apache.hadoop.hdfs.HsftpFileSystem
hive.map.aggr=true
hive.enforce.bucketing=false
mapred.task.tracker.http.address=0.0.0.0:50060
mapred.reduce.parallel.copies=5
io.seqfile.lazydecompress=true
hive.exec.script.allow.partial.consumption=false
io.sort.mb=100
ipc.client.connection.maxidletime=10000
mapred.task.tracker.report.address=127.0.0.1:0
mapred.compress.map.output=false
hive.mapred.reduce.tasks.speculative.execution=true
ipc.client.kill.max=10
ipc.client.connect.max.retries=10
hive.heartbeat.interval=1000
fs.s3.impl=org.apache.hadoop.fs.s3.S3FileSystem
hive.mapjoin.maxsize=100000
mapred.job.tracker.http.address=0.0.0.0:50030
io.file.buffer.size=4096
mapred.jobtracker.restart.recover=false
io.serializations=org.apache.hadoop.io.serializer.WritableSerialization
hive.optimize.cp=true
javax.jdo.option.NonTransactionalRead=true
hive.exec.reducers.bytes.per.reducer=1000000000
mapred.reduce.copy.backoff=300
mapred.task.profile=false
jobclient.output.filter=FAILED
mapred.tasktracker.map.tasks.maximum=2
io.compression.codecs=org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.BZip2Codec
fs.checkpoint.size=67108864