THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Why Replace the Existing Hive CLI?
Hive CLI is a legacy tool which had two main use cases. The first is that it served as a thick client for SQL on Hadoop and the second is that it served as a command line tool for Hive Server (the original Hive server, now often referred to as "HiveServer1"). Hive Server has been deprecated and removed from the Hive code base as of Hive 1.0.0 (HIVE-6977) and replaced with HiveServer2 (HIVE-2935), so the second use case no longer applies. For the first use case, Beeline provides or is supposed to provide equal functionality, yet is implemented differently from Hive CLI.
Ideally, Hive CLI should be deprecated as the Hive community has long recommended using the Beeline plus HiveServer2 configuration; however, because of the wide use of Hive CLI, we instead are replacing Hive CLI's implementation with a new Hive CLI on top of Beeline plus embedded HiveServer2 (HIVE-10511) so that the Hive community only needs to maintain a single code path. In this way, the new Hive CLI is just an alias to Beeline at both the shell script level and the high code level. The goal is that no or minimal changes are required from existing user scripts using Hive CLI.
Hive CLI Functionality Support
We use a new Hive CLI on top of Beeline to implement the Hive CLI functionality. In case some existing Hive CLI features are not supported in the new Hive CLI, we are able to use the following command to use the deprecated old Hive CLI tool.
export USE_DEPRECATED_CLI=true
Note that the log4j configuration file has been changed to "beeline-log4j.properties".
Hive CLI Options Support
To get help, run "hive -H" or "hive --help".
usage: hive
-d,--define <key=value> Variable subsitution to apply to hive
commands. e.g. -d A=B or --define A=B
--database <databasename> Specify the database to use
-e <quoted-query-string> SQL from command line
-f <filename> SQL from files
-H,--help Print help information
--hiveconf <property=value> Use value for given property
--hivevar <key=value> Variable subsitution to apply to hive
commands. e.g. --hivevar A=B
-i <filename> Initialization SQL file
-S,--silent Silent mode in interactive shell
-v,--verbose Verbose mode (echo executed SQL to the
console)
Examples
Example of running a query from the command line
$HIVE_HOME/bin/hive -e 'select a.foo from pokes a'
Example of setting Hive configuration variables
$HIVE_HOME/bin/hive -e 'select a.foo from pokes a' --hiveconf hive.exec.scratchdir=/opt/my/hive_scratch --hiveconf mapred.reduce.tasks=1
Example of dumping data out from a query into a file using silent mode
$HIVE_HOME/bin/hive -S -e 'select a.foo from pokes a' > a.txt
Example of running a script non-interactively from local disk
$HIVE_HOME/bin/hive -f /home/my/hive-script.sql
Example of running a script non-interactively from a Hadoop supported filesystem (starting in Hive 0.14)
$HIVE_HOME/bin/hive -f hdfs://<namenode>:<port>/hive-script.sql
Hive CLI Interactive Shell Commands Support
When $HIVE_HOME/bin/hive is run without either the -e or -f option, it enters interactive shell mode.
Use ";" (semicolon) to terminate commands. Comments in scripts can be specified using the "--" prefix.
Command | Description |
|---|---|
quit | Use quit or exit to leave the interactive shell. |
reset | Resets the configuration to the default values (as of Hive 0.10: see HIVE-3202). |
set <key>=<value> | Sets the value of a particular configuration variable (key). |
set | Prints a list of configuration variables that are overridden by the user or Hive. |
set -v | Prints all Hadoop and Hive configuration variables. |
add FILE[S] <filepath> <filepath>* | Adds one or more files, jars, or archives to the list of resources in the distributed cache. See Hive Resources for more information. |
| add FILE[S] <ivyurl> <ivyurl>* add JAR[S] <ivyurl> <ivyurl>* add ARCHIVE[S] <ivyurl> <ivyurl>* | As of Hive 1.2.0, adds one or more files, jars or archives to the list of resources in the distributed cache using an Ivy URL of the form ivy://group:module:version?query_string. See Hive Resources for more information. |
list FILE[S] | Lists the resources already added to the distributed cache. See Hive Resources for more information. |
list FILE[S] <filepath>* | Checks whether the given resources are already added to the distributed cache or not. See Hive Resources for more information. |
delete FILE[S] <filepath>* | Removes the resource(s) from the distributed cache. |
| delete FILE[S] <ivyurl> <ivyurl>* delete JAR[S] <ivyurl> <ivyurl>* delete ARCHIVE[S] <ivyurl> <ivyurl>* | As of Hive 1.2.0, removes the resource(s) which were added using the <ivyurl> from the distributed cache. See Hive Resources for more information. |
! <command> | Executes a shell command from the Hive shell. |
dfs <dfs command> | Executes a dfs command from the Hive shell. |
<query string> | Executes a Hive query and prints results to standard output. |
source FILE <filepath> | Executes a script file inside the CLI. |
Examples of shell commands:
hive> source /root/test.sql; hive> show tables; test1 test2 hive> exit; hive> quit; hive> set; hive> set hive.cli.print.header=true; hive> set -v; hive> reset; hive> add file /opt/a.txt; Added resources: [/opt/a.txt] hive> list files; /opt/a.txt hive> delete file /opt/a.txt; hive> add jar /usr/share/vnc/classes/vncviewer.jar; Added [/usr/share/vnc/classes/vncviewer.jar]to class path Added resources:[/usr/share/vnc/classes/vncviewer.jar] hive> list jars; /usr/share/vnc/classes/vncviewer.jar hive> delete jar /usr/share/vnc/classes/vncviewer.jar; hive> !ls; bin conf hive> dfs -ls / ; Found 2 items drwx-wx-wx - root supergroup 0 2015-08-12 19:06 /tmp drwxr-xr-x - root supergroup 0 2015-08-12 19:43 /user hive> select * from pokes; OK pokes.foo pokes.bar 238 val_238 86 val_86 311 val_311 hive>source /opt/s.sql;
Hive CLI Configuration Support
| Configuration Name | Supported in New Hive CLI | Description |
|---|---|---|
| hive.cli.print.header | Yes | Whether to print the names of the columns in query output. |
| hive.cli.errors.ignore | Yes | Whether to force execution of a script when errors occurred. |
| hive.cli.prompt | Yes | Command line prompt configuration value. Other hiveconf can be used in this configuration value. |
| hive.cli.pretty.output.num.cols | No | The number of columns to use when formatting output generated by the DESCRIBE PRETTY table_name command. |
| hive.cli.print.current.db | No | Whether to include the current database in the Hive prompt. |
Performance Impacts
Using the JMH to measure the average time cost when retrieving a data set, we have the following results.
Benchmark Mode Samples Score Error Units o.a.h.b.c.CliBench.BeeLineDriverBench.testSQLWithInitialFile avgt 1 1713326099.000 ? NaN ns/op o.a.h.b.c.CliBench.CliDriverBench.testSQLWithInitialFile avgt 1 1852995786.000 ? NaN ns/op
The lower the score the better since we are evaluating the time cost. There is no clear performance gap in terms of retrieving data.