第二章 impala基本使用
1、impala的使用
1.1、impala-shell语法
1.1.1、impala-shell的外部命令参数语法
不需要进入到impala-shell交互命令行当中即可执行的命令参数
impala-shell后面执行的时候可以带很多参数：
-h 查看帮助文档
impala-shell -h
[root@node03 hive-1.1.0-cdh5.14.0]# impala-shell -h
Usage: impala_shell.py [options]
Options:
-h, --help show this help message and exit
-i IMPALAD, --impalad=IMPALAD
<host:port> of impalad to connect to
[default: node03.hadoop.com:21000]
-q QUERY, --query=QUERY
Execute a query without the shell [default: none]
-f QUERY_FILE, --query_file=QUERY_FILE
Execute the queries in the query file, delimited by ;.
If the argument to -f is "-", then queries are read
from stdin and terminated with ctrl-d. [default: none]
-k, --kerberos Connect to a kerberized impalad [default: False]
-o OUTPUT_FILE, --output_file=OUTPUT_FILE
If set, query results are written to the g
-r 刷新整个元数据，数据量大的时候，比较消耗服务器性能
impala-shell -r
#结果
[root@node03 hive-1.1.0-cdh5.14.0]# impala-shell -r
Starting Impala Shell without Kerberos authentication
Connected to node03.hadoop.com:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
Invalidating Metadata
***********************************************************************************
Welcome to the Impala shell.
(Impala Shell v2.11.0-cdh5.14.0 (d682065) built on Sat Jan 6 13:27:16 PST 2018)
The HISTORY command lists all shell commands in chronological order.
***********************************************************************************
+==========================================================================+
| DEPRECATION WARNING: |
| -r/--refresh_after_connect is deprecated and will be removed in a future |
| version of Impala shell. |
+==========================================================================+
Query: invalidate metadata
Query submitted at: 2019-08-22 14:45:28 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=ce4db858e1dfd774:814fabac00000000
Fetched 0 row(s) in 5.04s
-B 去格式化，查询大量数据可以提高性能
--print_header 去格式化显示列名
--output_delimiter 指定分隔符
-v 查看对应版本
impala-shell -v -V
#结果
[root@node03 hive-1.1.0-cdh5.14.0]# impala-shell -v -V
Impala Shell v2.11.0-cdh5.14.0 (d682065) built on Sat Jan 6 13:27:16 PST 2018
-f 执行查询文件
--query_file 指定查询文件
cd /export/servers
vim impala-shell.sql
#写入下面两段话
use weblog;
select * from ods_click_pageviews limit 10;
#赋予可执行权限
chmod 755 imapala-shell.sql
#通过-f 参数来执行执行的查询文件
impala-shell -f impala-shell.sql
#结果
[root@node03 hivedatas]# impala-shell -f imapala-shell.sql
Starting Impala Shell without Kerberos authentication
Connected to node03.hadoop.com:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
Query: use hivesql
Query: select * from ods_click_pageviews limit 10
Query submitted at: 2019-08-22 15:29:54 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=6a4d51930cf99b9d:21f02c4e00000000
+--------------------------------------+-----------------+-------------+---------------------+----------------------------+------------+---------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+--------+----------+
| session | remote_addr | remote_user | time_local | request | visit_step | page_staylong | http_referer | http_user_agent | body_bytes_sent | status | datestr |
+--------------------------------------+-----------------+-------------+---------------------+----------------------------+------------+---------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+--------+----------+
| d1328698-d475-4973-86ee-15ad9da8c860 | 1.80.249.223 | - | 2013-09-18 07:57:33 | /hadoop-hive-intro/ | 1 | 60 | "http://www.google.com.hk/url?sa=t&rct=j&q=hive%E7%9A%84%E5%AE%89%E8%A3%85&source=web&cd=2&ved=0CC4QFjAB&url=%68%74%74%70%3a%2f%2f%62%6c%6f%67%2e%66%65%6e%73%2e%6d%65%2f%68%61%64%6f%6f%70%2d%68%69%76%65%2d%69%6e%74%72%6f%2f&ei=5lw5Uo-2NpGZiQfCwoG4BA&usg=AFQjCNF8EFxPuCMrm7CvqVgzcBUzrJZStQ&bvm=bv.52164340,d.aGc&cad=rjt" | "Mozilla/5.0(WindowsNT5.2;rv:23.0)Gecko/20100101Firefox/23.0" | 14764 | 200 | 20130918 |
| 0370aa09-ebd6-4d31-b6a5-469050a7fe61 | 101.226.167.201 | - | 2013-09-18 09:30:36 | /hadoop-mahout-roadmap/ | 1 | 60 | "http://blog.fens.me/hadoop-mahout-roadmap/"
-i 连接到impalad
--impalad 指定impalad去执行任务
-o 保存执行结果到文件当中去
--output_file 指定输出文件名
impala-shell -f impala-shell.sql -o fizz.txt
#结果
[root@node03 hivedatas]# impala-shell -f imapala-shell.sql -o fizz.txt
Starting Impala Shell without Kerberos authentication
Connected to node03.hadoop.com:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
Query: use hivesql
Query: select * from ods_click_pageviews limit 10
Query submitted at: 2019-08-22 15:31:45 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=7c421ab5d208f3b1:dec5a09300000000
Fetched 10 row(s) in 0.13s
#当前文件夹多了一个 fizz.txt 文件
[root@node03 hivedatas]# ll
total 2592
-rw-r--r-- 1 root root 511 Aug 21 2017 dim_time_dat.txt
-rw-r--r-- 1 root root 9926 Aug 22 15:31 fizz.txt
-rwxr-xr-x 1 root root 57 Aug 22 15:29 imapala-shell.sql
-rwxrwxrwx 1 root root 133 Aug 20 00:36 movie.txt
-rw-r--r-- 1 root root 18372 Jun 17 18:33 pageview2
-rwxr-xr-x 1 root root 154 Aug 20 00:32 test.txt
-rw-r--r-- 1 root root 327 Aug 20 02:37 user_table
-rw-r--r-- 1 root root 10361 Jun 18 09:00 visit2
-rw-r--r-- 1 root root 2587511 Jun 17 18:05 weblog2
-p 显示查询计划
impala-shell -f impala-shell.sql -p
-q 执行片段sql语句
impala-shell -q "use hivesql;select * from ods_click_pageviews limit 10;"
[root@node03 hivedatas]# impala-shell -q "use hivesql;select * from ods_click_pageviews limit 10;"
Starting Impala Shell without Kerberos authentication
Connected to node03.hadoop.com:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
Query: use hivesql
Query: select * from ods_click_pageviews limit 10
Query submitted at: 2019-08-22 15:36:58 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=b443d56565419f60:a149235700000000
+--------------------------------------+-----------------+-------------+---------------------+----------------------------+------------+---------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+--------+----------+
| session | remote_addr | remote_user | time_local | request | visit_step | page_staylong | http_referer | http_user_agent | body_bytes_sent | status | datestr |
1.1.2、impala-shell的内部命令行参数语法
进入impala-shell命令行之后可以执行的语法
进入impala-shell：
impala-shell #任意目录
#结果
[root@node03 hivedatas]# impala-shell
Starting Impala Shell without Kerberos authentication
Connected to node03.hadoop.com:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
***********************************************************************************
Welcome to the Impala shell.
(Impala Shell v2.11.0-cdh5.14.0 (d682065) built on Sat Jan 6 13:27:16 PST 2018)
To see more tips, run the TIP command.
***********************************************************************************
[node03.hadoop.com:21000] >
help命令
帮助文档
[node03.hadoop.com:21000] > help;
Documented commands (type help <topic>):
========================================
compute describe explain profile rerun set show unset values with
connect exit history quit select shell tip use version
Undocumented commands:
======================
alter delete drop insert source summary upsert
create desc help load src update
connect命令
connect hostname 连接到某一台机器上面去执行
connect node02;
#结果
[node03.hadoop.com:21000] > connect node02;
Connected to node02:21000
Server version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
[node02:21000] >
refresh命令
refresh dbname.tablename 增量刷新，刷新某一张表的元数据，主要用于刷新hive当中数据表里面的数据改变的情况
用于刷新hive当中数据表里面的数据改变的情况
refresh movie_info;
#结果
[node03:21000] > refresh movie_info;
Query: refresh movie_info
Query submitted at: 2019-08-22 15:49:24 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=f74330d533ff2402:27364f7600000000
Fetched 0 row(s) in 0.27s
invalidate metadata 命令：
invalidate metadata全量刷新，性能消耗较大，主要用于hive当中新建数据库或者数据库表的时候来进行刷新
invalidate metadata;
#结果
[node03:21000] > invalidate metadata;
Query: invalidate metadata
Query submitted at: 2019-08-22 15:48:04 (Coordinator: http://node03.hadoop.com:25000)
Query progress can be monitored at: http://node03.hadoop.com:25000/query_plan?query_id=6a431748d41bc369:7eeb053400000000
Fetched 0 row(s) in 2.87s
explain 命令：
用于查看sql语句的执行计划
explain select * from stu;
#结果
[node03:21000] > explain select * from user_table;
Query: explain select * from user_table
+------------------------------------------------------------------------------------+
| Explain String |
+------------------------------------------------------------------------------------+
| Max Per-Host Resource Reservation: Memory=0B |
| Per-Host Resource Estimates: Memory=32.00MB |
| WARNING: The following tables are missing relevant table and/or column statistics. |
| hivesql.user_table |
| |
| PLAN-ROOT SINK |
| | |
| 01:EXCHANGE [UNPARTITIONED] |
| | |
| 00:SCAN HDFS [hivesql.user_table] |
| partitions=1/1 files=1 size=327B |
+------------------------------------------------------------------------------------+
Fetched 11 row(s) in 3.99s
explain的值可以设置成0,1,2,3等几个值，其中3级别是最高的，可以打印出最全的信息
set explain_level=3;
#结果
[node03:21000] > set explain_level=3;
EXPLAIN_LEVEL set to 3
[node03:21000] >
profile命令：
执行sql语句之后执行，可以打印出更加详细的执行步骤，
主要用于查询结果的查看，集群的调优等
select * from user_table;
profile;
#部分结果截取
[node03:21000] > profile;
Query Runtime Profile:
Query (id=ff4799938b710fbb:7997836800000000):
Summary:
Session ID: a14d3b3894050309:7f300ddf8dcd8584
Session Type: BEESWAX
Start Time: 2019-08-22 15:58:22.786612000
End Time: 2019-08-22 15:58:24.558806000
Query Type: QUERY
Query State: FINISHED
Query Status: OK
Impala Version: impalad version 2.11.0-cdh5.14.0 RELEASE (build d68206561bce6b26762d62c01a78e6cd27aa7690)
User: root
Connected User: root
Delegated User:
Network Address: ::ffff:192.168.52.120:48318
Default Db: hivesql
Sql Statement: select * from user_table
Coordinator: node03.hadoop.com:22000
Query Options (set by configuration): EXPLAIN_LEVEL=3
Query Options (set by configuration and planner): EXPLAIN_LEVEL=3,MT_DOP=0
Plan:
注意:在hive窗口当中插入的数据或者新建的数据库或者数据库表，在impala当中是不可直接查询到的，需要刷新数据库，在impala-shell当中插入的数据，在impala当中是可以直接查询到的，不需要刷新数据库，其中使用的就是catalog这个服务的功能实现的，catalog是impala1.2版本之后增加的模块功能，主要作用就是同步impala之间的元数据
1.2、创建数据库
1.1.1进入impala交互窗口
impala-shell #进入到impala的交互窗口
1.1.2查看所有数据库
show databases;
1.1.3创建与删除数据库
创建数据库
CREATE DATABASE IF NOT EXISTS mydb1;
drop database if exists mydb;
1.3、 创建数据库表
创建student表
CREATE TABLE IF NOT EXISTS mydb1.student (name STRING, age INT, contact INT );
创建employ表
create table employee (Id INT, name STRING, age INT,address STRING, salary BIGINT);
1.3.1、 数据库表中插入数据
insert into employee (ID,NAME,AGE,ADDRESS,SALARY)VALUES (1, 'Ramesh', 32, 'Ahmedabad', 20000 );
insert into employee values (2, 'Khilan', 25, 'Delhi', 15000 );
Insert into employee values (3, 'kaushik', 23, 'Kota', 30000 );
Insert into employee values (4, 'Chaitali', 25, 'Mumbai', 35000 );
Insert into employee values (5, 'Hardik', 27, 'Bhopal', 40000 );
Insert into employee values (6, 'Komal', 22, 'MP', 32000 );
数据的覆盖
Insert overwrite employee values (1, 'Ram', 26, 'Vishakhapatnam', 37000 );
执行覆盖之后，表中只剩下了这一条数据了
另外一种建表语句
create table customer as select * from employee;
1.3.2、 数据的查询
select * from employee;
select name,age from employee;
1.3.3、 删除表
DROP table mydb1.employee;
1.3.4、 清空表数据
truncate employee;
1.3.5、 创建视图
CREATE VIEW IF NOT EXISTS employee_view AS select name, age from employee;
1.3.6、 查看视图数据
select * from employee_view;
1.4、order by语句
基础语法
select * from table_name ORDER BY col_name [ASC|DESC] [NULLS FIRST|NULLS LAST]
Select * from employee ORDER BY id asc;
1.5、group by 语句
Select name, sum(salary) from employee Group BY name;
1.6、 having 语句
基础语法
select * from table_name ORDER BY col_name [ASC|DESC] [NULLS FIRST|NULLS LAST]
按年龄对表进行分组，并选择每个组的最大工资，并显示大于20000的工资
select max(salary) from employee group by age having max(salary) > 20000
1.7、 limit语句
select * from employee order by id limit 4;
2、impala当中的数据表导入几种方式
第一种方式，通过load hdfs的数据到impala当中去
create table user(id int ,name string,age int ) row format delimited fields terminated by "\t";
准备数据user.txt并上传到hdfs的 /user/impala路径下去
上传user.txt到hadoop上去：
hdfs dfs -put user.txt /user/impala/
查看是否上传成功：
hdfs dfs -ls /user/impala
1 kasha 15
2 fizz 20
3 pheonux 30
4 manzi 50
加载数据
load data inpath '/user/impala/' into table user;
查询加载的数据
select * from user;
如果查询不不到数据，那么需要刷新一遍数据表
refresh user;
第二种方式：
create table user2 as select * from user;
第三种方式：
insert into #不推荐使用 因为会产生大量的小文件
千万不要把impala当做一个数据库来使用
第四种方式：
insert into select #用的比较多
