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impala/shell/README.md
Joe McDonnell ea0969a772 IMPALA-11980 (part 2): Fix absolute import issues for impala_shell
Python 3 changed the behavior of imports with PEP328. Existing
imports become absolute unless they use the new relative import
syntax. This adapts the impala-shell code to use absolute
imports, fixing issues where it is imported from our test code.

There are several parts to this:
1. It moves impala shell code into shell/impala_shell.
   This matches the directory structure of the PyPi package.
2. It changes the imports in the shell code to be
   absolute paths (i.e. impala_shell.foo rather than foo).
   This fixes issues with Python 3 absolute imports.
   It also eliminates the need for ugly hacks in the PyPi
   package's __init__.py.
3. This changes Thrift generation to put it directly in
   $IMPALA_HOME/shell rather than $IMPALA_HOME/shell/gen-py.
   This means that the generated Thrift code is rooted in
   the same directory as the shell code.
4. This changes the PYTHONPATH to include $IMPALA_HOME/shell
   and not $IMPALA_HOME/shell/gen-py. This means that the
   test code is using the same import paths as the pypi
   package.

With all of these changes, the source code is very close
to the directory structure of the PyPi package. As long as
CMake has generated the thrift files and the Python version
file, only a few differences remain. This removes those
differences by moving the setup.py / MANIFEST.in and other
files from the packaging directory to the top-level
shell/ directory. This means that one can pip install
directly from the source code. i.e. pip install $IMPALA_HOME/shell

This also moves the shell tarball generation script to the
packaging directory and changes bin/impala-shell.sh to use
Python 3.

This sorts the imports using isort for the affected Python files.

Testing:
 - Ran a regular core job with Python 2
 - Ran a core job with Python 3 and verified that the absolute
   import issues are gone.

Change-Id: Ica75a24fa6bcb78999b9b6f4f4356951b81c3124
Reviewed-on: http://gerrit.cloudera.org:8080/22330
Reviewed-by: Riza Suminto <riza.suminto@cloudera.com>
Reviewed-by: Michael Smith <michael.smith@cloudera.com>
Tested-by: Riza Suminto <riza.suminto@cloudera.com>
2025-05-21 15:14:11 +00:00

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# Impala Interactive Shell
You can use the Impala shell tool (impala-shell) to connect to an Impala
service. The shell allows you to set up databases and tables, insert data,
and issue queries. For ad hoc queries and exploration, you can submit SQL
statements in an interactive session. The impala-shell interpreter accepts
all the same SQL statements listed in
[Impala SQL Statements](http://impala.apache.org/docs/build/html/topics/impala_langref_sql.html),
plus some shell-only commands that you can use for tuning performance and
diagnosing problems.
To automate your work, you can specify command-line options to process a single
statement or a script file. (Other avenues for Impala automation via python
are provided by Impyla or ODBC.)
## Installing
```
$ pip install impala-shell
```
## Online documentation
* [Impala Shell Documentation](http://impala.apache.org/docs/build/html/topics/impala_impala_shell.html)
* [Apache Impala Documentation](http://impala.apache.org/impala-docs.html)
## Quickstart
### Non-interactive mode
Processing a single query, e.g., ```show tables```:
```
$ impala-shell -i impalad-host.domain.com -d some_database -q 'show tables'
```
Processing a text file with a series of queries:
```
$ impala-shell -i impalad-host.domain.com -d some_database -f /path/to/queries.sql
```
### Launching the interactive shell
To connect to an impalad host at the default service port (21000):
```
$ impala-shell -i impalad-host.domain.com
Starting Impala Shell without Kerberos authentication
Connected to impalad-host.domain.com:21000
Server version: impalad version 2.11.0-SNAPSHOT RELEASE (build d4596f9ca3ea32a8008cdc809a7ac9a3dea47962)
***********************************************************************************
Welcome to the Impala shell.
(Impala Shell v3.0.0-SNAPSHOT (73e90d2) built on Thu Mar 8 00:59:00 PST 2018)
The '-B' command line flag turns off pretty-printing for query results. Use this
flag to remove formatting from results you want to save for later, or to benchmark
Impala.
***********************************************************************************
[impalad-host.domain.com:21000] >
```
### Launching the interactive shell (secure mode)
To connect to a secure host using kerberos and SSL:
```
$ impala-shell -k --ssl -i impalad-secure-host.domain.com
```
### Disconnecting
To exit the shell when running interactively, press ```Ctrl-D``` at the shell prompt.