PostgreSQL 字段使用pglz压缩测试

测试一：

创建测试表 yewu1.test1，并插入1000w行数据
创建测试表 yewu1.test2，使用 pglz压缩字段，并插入1000w行数据

–创建测试表1，并插入1000w行数据

white=# create table yewu1.test1 (name varchar(20));
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test1'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | 
(7 rows)
white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test1 VALUES ('white ' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test1')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

–创建测试表2，使用 pglz压缩字段，并插入1000w行数据

white=# 
white=# create table yewu1.test2 (name varchar(20) COMPRESSION pglz);
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test2'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | p
(7 rows)
white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test2 VALUES ('white ' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test2')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

对比表yewu1.test1和yewu1.test2的大小，没体现出压缩了。

测试二：

创建测试表 yewu1.test3，text数据类型，并插入1000w行数据
创建测试表 yewu1.test4，text数据类型，使用 pglz压缩字段，并插入1000w行数据

–创建测试表3，并插入1000w行数据

white=# create table yewu1.test3 (name text);
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test3'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | 
(7 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test3 VALUES ('white ' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test3')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

–创建测试表4，使用 pglz压缩字段，并插入1000w行数据

white=# create table yewu1.test4 (name text COMPRESSION pglz);
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test4'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | p
(7 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test4 VALUES ('white ' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test4')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

对比表yewu1.test3和yewu1.test4的大小，没体现出压缩了。

测试三：

创建测试表 yewu1.test5，text数据类型，并插入1000w行重复的数据
创建测试表 yewu1.test6，text数据类型，使用 pglz压缩字段，并插入1000w行重复的数据

–创建测试表5，并插入1000w行重复的数据

white=# create table yewu1.test5 (name text);
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test5'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | 
(7 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test5 VALUES ('white12345678');
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test5')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

–创建测试表6，使用 pglz压缩字段，并插入1000w行重复的数据

white=# create table yewu1.test6 (name text COMPRESSION pglz);
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test6'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 name     | p
(7 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test6 VALUES ('white12345678');
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test6')) AS table_size;
 table_size 
------------
 422 MB
(1 row)

对比表yewu1.test5和yewu1.test6的大小，没体现出压缩了。

测试四：

创建测试表 yewu1.test7，带有主键，text数据类型，并插入1000w行重复的数据
创建测试表 yewu1.test8，带有主键，text数据类型，使用 pglz压缩字段，并插入1000w行重复的数据

–创建测试表7，带有主键，并插入1000w行重复的数据

white=# create table yewu1.test7 (
white(#     id serial primary key,
white(#     name text
white(# );
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test7'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 id       | 
 name     | 
(8 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test7 VALUES (aa,'white' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test7')) AS table_size;
 table_size 
------------
 490 MB
(1 row)

–创建测试表8，带有主键，使用 pglz压缩字段，并插入1000w行重复的数据

white=# create table yewu1.test8 (
white(#     id serial primary key,
white(#     name text COMPRESSION pglz
white(# );
CREATE TABLE
white=# 
white=# SELECT attname, attcompression
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test8'::regclass;
 attname  | attcompression 
----------+----------------
 tableoid | 
 cmax     | 
 xmax     | 
 cmin     | 
 xmin     | 
 ctid     | 
 id       | 
 name     | p
(8 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test8 VALUES (aa,'white' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test8')) AS table_size;
 table_size 
------------
 490 MB
(1 row)

对比表yewu1.test7和yewu1.test8的大小，没体现出压缩了。

测试五：

清空测试表 yewu1.test8，并修改字段存储类型为MAIN，再插入1000w行重复的数据

–清空测试表8，并修改字段存储类型为MAIN，再插入1000w行重复的数据

white=# truncate table yewu1.test8;
TRUNCATE TABLE
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test8')) AS table_size;
 table_size 
------------
 8192 bytes
(1 row)

white=# 
white=# SELECT attname, attcompression,attstorage
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test8'::regclass;
 attname  | attcompression | attstorage 
----------+----------------+------------
 tableoid |                | p
 cmax     |                | p
 xmax     |                | p
 cmin     |                | p
 xmin     |                | p
 ctid     |                | p
 id       |                | p
 name     | p              | x
(8 rows)

white=# 
white=# ALTER TABLE yewu1.test8 ALTER COLUMN name SET STORAGE MAIN;
ALTER TABLE
white=# SELECT attname, attcompression,attstorage
white-# FROM pg_attribute
white-# WHERE attrelid = 'yewu1.test8'::regclass;
 attname  | attcompression | attstorage 
----------+----------------+------------
 tableoid |                | p
 cmax     |                | p
 xmax     |                | p
 cmin     |                | p
 xmin     |                | p
 ctid     |                | p
 id       |                | p
 name     | p              | m
(8 rows)

white=# 
white=# DO $$
white$# DECLARE aa INTEGER;
white$# BEGIN
white$#     FOR aa IN 1..10000000 LOOP
white$#         INSERT INTO yewu1.test8 VALUES (aa,'white' || aa);
white$# END LOOP;
white$# COMMIT;
white$# END $$;
DO
white=# 
white=# SELECT pg_size_pretty(pg_table_size('yewu1.test8')) AS table_size;
 table_size 
------------
 490 MB
(1 row)

–未完待续。思路错了，pg的压缩表有限制