- OLAP工具 - Impala导航
- Impala 简介
- Impala 安装
- Impala 启动
- Impala 入门实例
- Impala 从本地文件加载CSV数据
- Impala 将Impala表指向现有数据文件
- Impala 查询Impala表
- Impala 将外部分区表附加到HDFS目录结构
- Impala Hive转换
- Impala 交叉连接和笛卡尔积
- Impala 处理Parquet文件
- Impala 分区表-1
- Impala 分区表-2
- Impala 处理Hadoop文件格式
- Impala 使用文本数据文件
- Impala 使用Parquet文件格式
- Impala 使用Avro文件格式
- Impala 使用ORC文件格式
- Impala 使用Hudi文件格式
- Impala 使用RCFile文件格式
- Impala 使用SequenceFile文件格式
- Impala 查询Kudu表
- Impala 查询HBase表
- Impala 与Amazon S3对象结合使用
- Impala Azure Data Lake Store(ADLS) 结合使用
- Impala 使用Isilon存储
- Impala 客户端访问
- Impala 使用Impala Shell
- Impala impala-shell 配置选项
- Impala-shell 连接到Impala Daemon
- Impala-shell 运行SQL语句
- Impala-shell 命令参考
- Impala 配置JDBC
Impala 分区表-2
WHEREYEARYEAR=2010
[localhost:21000] > drop table census;
[localhost:21000] > create table census (name string, census_year int) partitioned by (year int);
[localhost:21000] > insert into census partition (year=2010) values ('Smith',2010),('Jones',2010);
[localhost:21000] > insert into census partition (year=2011) values ('Smith',2020),('Jones',2020),('Doe',2020);
[localhost:21000] > insert into census partition (year=2012) values ('Smith',2020),('Doe',2020);
[localhost:21000] > select name from census where year = census_year and census_year=2010;
+-------+
| name |
+-------+
| Smith |
| Jones |
+-------+
[localhost:21000] > explain select name from census where year = census_year and census_year=2010;
+------------------------------------------------------------------+
| Explain String |
+------------------------------------------------------------------+
| PLAN FRAGMENT 0 |
| PARTITION: UNPARTITIONED |
| |
| 1:EXCHANGE |
| |
| PLAN FRAGMENT 1 |
| PARTITION: RANDOM |
| |
| STREAM DATA SINK |
| EXCHANGE ID: 1 |
| UNPARTITIONED |
| |
| 0:SCAN HDFS |
| table=predicate_propagation.census #partitions=1/3 size=22B |
| predicates: census_year = 2010, year = census_year |
+------------------------------------------------------------------+WHEREWHERECREATE VIEW
PARTITION BYWHERE year=2016YEARPARTITION BY yearOVER (PARTITION BY year,other_columns other_analytic_clauses)
WHERE
WHERE
-- The query only needs to read 3 partitions whose key values are known ahead of time.
-- That's static partition pruning.
SELECT COUNT(*) FROM sales_table WHERE year IN (2005, 2010, 2015);
CREATE TABLE yy (s STRING) PARTITIONED BY (year INT);
INSERT INTO yy PARTITION (year) VALUES ('1999', 1999), ('2000', 2000),
('2001', 2001), ('2010', 2010), ('2018', 2018);
COMPUTE STATS yy;
CREATE TABLE yy2 (s STRING, year INT);
INSERT INTO yy2 VALUES ('1999', 1999), ('2000', 2000), ('2001', 2001);
COMPUTE STATS yy2;
-- The following query reads an unknown number of partitions, whose key values
-- are only known at run time. The runtime filters line shows the
-- information used in query fragment 02 to decide which partitions to skip.
EXPLAIN SELECT s FROM yy WHERE year IN (SELECT year FROM yy2);
+--------------------------------------------------------------------------+
| PLAN-ROOT SINK |
| | |
| 04:EXCHANGE [UNPARTITIONED] |
| | |
| 02:HASH JOIN [LEFT SEMI JOIN, BROADCAST] |
| | hash predicates: year = year |
| | runtime filters: RF000 <- year |
| | |
| |--03:EXCHANGE [BROADCAST] |
| | | |
| | 01:SCAN HDFS [default.yy2] |
| | partitions=1/1 files=1 size=620B |
| | |
| 00:SCAN HDFS [default.yy] |
| partitions=5/5 files=5 size=1.71KB |
| runtime filters: RF000 -> year |
+--------------------------------------------------------------------------+
SELECT s FROM yy WHERE year IN (SELECT year FROM yy2); -- Returns 3 rows from yy
PROFILE;
EXPLAINyy
PROFILE
Filter 0 (1.00 MB):
- Files processed: 3
- Files rejected: 1 (1)
- Files total: 3 (3)ONWHEREON
TIMESTAMPOPTIMIZE_PARTITION_KEY_SCANSSELECT MAX(year)
MIN()MAX()COUNT(DISTINCT)OPTIMIZE_PARTITION_KEY_SCANS
[localhost:21000] > create table census (name string) partitioned by (year smallint);
[localhost:21000] > alter table census add partition (year=2012); -- Text format;
[localhost:21000] > alter table census add partition (year=2013); -- Text format switches to Parquet before data loaded;
[localhost:21000] > alter table census partition (year=2013) set fileformat parquet;
[localhost:21000] > insert into census partition (year=2012) values ('Smith'),('Jones'),('Lee'),('Singh');
[localhost:21000] > insert into census partition (year=2013) values ('Flores'),('Bogomolov'),('Cooper'),('Appiah');year=2012year=2013INSERT ... SELECTLOAD DATAINSERT ... VALUES
ALTER TABLE ... SET FILEFORMATINSERTLOAD DATAREFRESH table_name
注意：ALTER TABLEADD PARTITIONLOCATIONADD PARTITIONSET LOCATION
PARTITION BYCREATE TABLE
COMPUTE STATS
重要的：
COMPUTE STATSCOMPUTE INCREMENTAL STATSCOMPUTE STATSCOMPUTE INCREMENTAL STATSDROP STATS
COMPUTE INCREMENTAL STATSCOMPUTE INCREMENTAL STATS
COMPUTE INCREMENTAL STATSCOMPUTE INCREMENTAL STATSCOMPUTE STATS
-- Initially the table has no incremental stats, as indicated
-- 'false' under Incremental stats.
show table stats item_partitioned;
+-------------+-------+--------+----------+--------------+---------+------------------
| i_category | #Rows | #Files | Size | Bytes Cached | Format | Incremental stats
+-------------+-------+--------+----------+--------------+---------+------------------
| Books | -1 | 1 | 223.74KB | NOT CACHED | PARQUET | false
| Children | -1 | 1 | 230.05KB | NOT CACHED | PARQUET | false
| Electronics | -1 | 1 | 232.67KB | NOT CACHED | PARQUET | false
| Home | -1 | 1 | 232.56KB | NOT CACHED | PARQUET | false
| Jewelry | -1 | 1 | 223.72KB | NOT CACHED | PARQUET | false
| Men | -1 | 1 | 231.25KB | NOT CACHED | PARQUET | false
| Music | -1 | 1 | 237.90KB | NOT CACHED | PARQUET | false
| Shoes | -1 | 1 | 234.90KB | NOT CACHED | PARQUET | false
| Sports | -1 | 1 | 227.97KB | NOT CACHED | PARQUET | false
| Women | -1 | 1 | 226.27KB | NOT CACHED | PARQUET | false
| Total | -1 | 10 | 2.25MB | 0B | |
+-------------+-------+--------+----------+--------------+---------+------------------
-- After the first COMPUTE INCREMENTAL STATS,
-- all partitions have stats. The first
-- COMPUTE INCREMENTAL STATS scans the whole
-- table, discarding any previous stats from
-- a traditional COMPUTE STATS statement.
compute incremental stats item_partitioned;
+-------------------------------------------+
| summary |
+-------------------------------------------+
| Updated 10 partition(s) and 21 column(s). |
+-------------------------------------------+
show table stats item_partitioned;
+-------------+-------+--------+----------+--------------+---------+------------------
| i_category | #Rows | #Files | Size | Bytes Cached | Format | Incremental stats
+-------------+-------+--------+----------+--------------+---------+------------------
| Books | 1733 | 1 | 223.74KB | NOT CACHED | PARQUET | true
| Children | 1786 | 1 | 230.05KB | NOT CACHED | PARQUET | true
| Electronics | 1812 | 1 | 232.67KB | NOT CACHED | PARQUET | true
| Home | 1807 | 1 | 232.56KB | NOT CACHED | PARQUET | true
| Jewelry | 1740 | 1 | 223.72KB | NOT CACHED | PARQUET | true
| Men | 1811 | 1 | 231.25KB | NOT CACHED | PARQUET | true
| Music | 1860 | 1 | 237.90KB | NOT CACHED | PARQUET | true
| Shoes | 1835 | 1 | 234.90KB | NOT CACHED | PARQUET | true
| Sports | 1783 | 1 | 227.97KB | NOT CACHED | PARQUET | true
| Women | 1790 | 1 | 226.27KB | NOT CACHED | PARQUET | true
| Total | 17957 | 10 | 2.25MB | 0B | |
+-------------+-------+--------+----------+--------------+---------+------------------
-- Add a new partition...
alter table item_partitioned add partition (i_category='Camping');
-- Add or replace files in HDFS outside of Impala,
-- rendering the stats for a partition obsolete.
!import_data_into_sports_partition.sh
refresh item_partitioned;
drop incremental stats item_partitioned partition (i_category='Sports');
-- Now some partitions have incremental stats
-- and some do not.
show table stats item_partitioned;
+-------------+-------+--------+----------+--------------+---------+------------------
| i_category | #Rows | #Files | Size | Bytes Cached | Format | Incremental stats
+-------------+-------+--------+----------+--------------+---------+------------------
| Books | 1733 | 1 | 223.74KB | NOT CACHED | PARQUET | true
| Camping | -1 | 1 | 408.02KB | NOT CACHED | PARQUET | false
| Children | 1786 | 1 | 230.05KB | NOT CACHED | PARQUET | true
| Electronics | 1812 | 1 | 232.67KB | NOT CACHED | PARQUET | true
| Home | 1807 | 1 | 232.56KB | NOT CACHED | PARQUET | true
| Jewelry | 1740 | 1 | 223.72KB | NOT CACHED | PARQUET | true
| Men | 1811 | 1 | 231.25KB | NOT CACHED | PARQUET | true
| Music | 1860 | 1 | 237.90KB | NOT CACHED | PARQUET | true
| Shoes | 1835 | 1 | 234.90KB | NOT CACHED | PARQUET | true
| Sports | -1 | 1 | 227.97KB | NOT CACHED | PARQUET | false
| Women | 1790 | 1 | 226.27KB | NOT CACHED | PARQUET | true
| Total | 17957 | 11 | 2.65MB | 0B | |
+-------------+-------+--------+----------+--------------+---------+------------------
-- After another COMPUTE INCREMENTAL STATS,
-- all partitions have incremental stats, and only the 2
-- partitions without incremental stats were scanned.
compute incremental stats item_partitioned;
+------------------------------------------+
| summary |
+------------------------------------------+
| Updated 2 partition(s) and 21 column(s). |
+------------------------------------------+
show table stats item_partitioned;
+-------------+-------+--------+----------+--------------+---------+------------------
| i_category | #Rows | #Files | Size | Bytes Cached | Format | Incremental stats
+-------------+-------+--------+----------+--------------+---------+------------------
| Books | 1733 | 1 | 223.74KB | NOT CACHED | PARQUET | true
| Camping | 5328 | 1 | 408.02KB | NOT CACHED | PARQUET | true
| Children | 1786 | 1 | 230.05KB | NOT CACHED | PARQUET | true
| Electronics | 1812 | 1 | 232.67KB | NOT CACHED | PARQUET | true
| Home | 1807 | 1 | 232.56KB | NOT CACHED | PARQUET | true
| Jewelry | 1740 | 1 | 223.72KB | NOT CACHED | PARQUET | true
| Men | 1811 | 1 | 231.25KB | NOT CACHED | PARQUET | true
| Music | 1860 | 1 | 237.90KB | NOT CACHED | PARQUET | true
| Shoes | 1835 | 1 | 234.90KB | NOT CACHED | PARQUET | true
| Sports | 1783 | 1 | 227.97KB | NOT CACHED | PARQUET | true
| Women | 1790 | 1 | 226.27KB | NOT CACHED | PARQUET | true
| Total | 17957 | 11 | 2.65MB | 0B | |
+-------------+-------+--------+----------+--------------+---------+------------------
