课程学习内容
软件版本 ：openGauss 3.0.0
表空间是数据的容器。掌握表空间的管理，包括创建表空间、删除表空间、重命名表空间、查看表空间的情况。
数据库实操内容
通过使用表空间，管理员可以控制一个数据库安装的磁盘布局。
表空间对应于一个文件系统目录，假定数据库节点数据目录/pg_location/mount1/path1是用户拥有读写权限的空目录。
openGauss自带了两个表空间：pg_default和pg_global。
默认表空间pg_default：用来存储非共享系统表、用户表、用户表index、临时表、临时表index、内部临时表的默认表空间。对应存储目录为实例数据目录下的base目录。
共享表空间pg_global：用来存放共享系统表的表空间。对应存储目录为实例数据目录下的global目录。
环境准备
连接数据库 #第一次进入等待15秒 #数据库启动中…
su - omm
gsql -r
root@modb:~# su - omm omm@modb:~$ gsql -r gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr ) Non-SSL connection (SSL connection is recommended when requiring high-security) Type "help" for help. omm=#
执行如下命令创建用户jack
CREATE USER jack IDENTIFIED BY ‘kunpeng@1234’;
omm=# CREATE USER jack IDENTIFIED BY 'kunpeng@1234'; NOTICE: The encrypted password contains MD5 ciphertext, which is not secure. CREATE ROLE omm=#
创建表空间、表
–执行下面的SQL语句，创建表空间t_tbspace：
CREATE TABLESPACE t_tbspace RELATIVE LOCATION ‘tablespace/t_tbspace1’;
omm=# CREATE TABLESPACE t_tbspace RELATIVE LOCATION 'tablespace/t_tbspace1'; CREATE TABLESPACE omm=#
–查看系统有哪些表空间
select oid,* from pg_tablespace ;
或
\db
omm=# select oid,* from pg_tablespace ; oid | spcname | spcowner | spcacl | spcoptions | spcmaxsize | relative -------+------------+----------+--------+------------+------------+---------- 1663 | pg_default | 10 | | | | f 1664 | pg_global | 10 | | | | f 16393 | t_tbspace | 10 | | | | t (3 rows) omm=# \db List of tablespaces Name | Owner | Location ------------+-------+----------------------- pg_default | omm | pg_global | omm | t_tbspace | omm | tablespace/t_tbspace1 (3 rows) omm=#
–数据库系统管理员执行如下命令将“t_tbspace”表空间的访问权限赋予数据用户jack。
GRANT CREATE ON TABLESPACE t_tbspace TO jack;
omm=# GRANT CREATE ON TABLESPACE t_tbspace TO jack; GRANT
–执行如下命令，使用jack用户在指定表空间t_tbspace创建表。
\c omm jack
CREATE TABLE foo(i int) TABLESPACE t_tbspace;
\q
omm=# \c omm jack Password for user jack: Non-SSL connection (SSL connection is recommended when requiring high-security) You are now connected to database "omm" as user "jack". omm=> CREATE TABLE foo(i int) TABLESPACE t_tbspace; CREATE TABLE omm=> \q omm@modb:~$
查看表空间t_tbspace的大小
gsql -r
SELECT PG_TABLESPACE_SIZE(‘t_tbspace’);
omm=# SELECT PG_TABLESPACE_SIZE('t_tbspace'); omm=# pg_tablespace_size -------------------- 8192 (1 row) omm=#
查看数据库在默认表空间下有哪些对象
with objectInDefaultTS as ( select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)), reltablespace,relowner from pg_class a where a.relkind in (‘r’, ‘i’) and reltablespace=‘0’ ) select * from objectInDefaultTS where relname not like ‘pg_%’ and relname not like ‘gs_%’ and relname not like ‘sql_%’ order by relpages desc;
omm=# with objectInDefaultTS as ( select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)), reltablespace,relowner from pg_class a where a.relkind in ('r', 'i') and reltablespace='0' ) select * from objectInDefaultTS where relname not like 'pg_%' and relname not like 'gs_%' and relname not like 'sql_%' order by relpages desc; relname | relkind | relpages | pg_size_pretty | reltablespace | relowner ------------------------------------------+---------+----------+----------------+---------------+---------- streaming_gather_agg_index | i | 2 | 16 kB | 0 | 10 snapshot_id_key | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_lookupidxid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_schema_change_index | i | 1 | 8192 bytes | 0 | 10 streaming_reaper_status_id_index | i | 1 | 8192 bytes | 0 | 10 streaming_reaper_status_oid_index | i | 1 | 8192 bytes | 0 | 10 snapshot_pkey | i | 1 | 8192 bytes | 0 | 10 statement_history_time_idx | i | 1 | 8192 bytes | 0 | 10 streaming_stream_oid_index | i | 1 | 8192 bytes | 0 | 10 streaming_stream_relid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_relid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_defrelid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_id_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_oid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_matrelid_index | i | 1 | 8192 bytes | 0 | 10 snapshot | r | 0 | 0 bytes | 0 | 10 plan_table_data | r | 0 | 0 bytes | 0 | 10 statement_history | r | 0 | 0 bytes | 0 | 10 streaming_stream | r | 0 | 0 bytes | 0 | 10 streaming_cont_query | r | 0 | 0 bytes | 0 | 10 --More-- streaming_reaper_status | r | 0 | 0 bytes | 0 | 10 (21 rows) omm=#
查看数据库在非默认表空间下有哪些对象
–执行下面的SQL语句，查询数据库studentdb的非默认表空间t_tbspace下有哪些对象：
select relname,relkind,relpages,pg_size_pretty(pg_relation_size(a.oid)), reltablespace,relowner from pg_class a, pg_tablespace tb where a.relkind in (‘r’, ‘i’) and a.reltablespace=tb.oid and tb.spcname=‘t_tbspace’ order by a.relpages desc;
omm=# select relname,relkind,relpages,pg_size_pretty(pg_relation_size(a.oid)), reltablespace,relowner from pg_class a, pg_tablespace tb where a.relkind in ('r', 'i') and a.reltablespace=tb.oid and tb.spcname='t_tbspace' order by a.relpages desc; omm=# relname | relkind | relpages | pg_size_pretty | reltablespace | relowner ---------+---------+----------+----------------+---------------+---------- foo | r | 0 | 0 bytes | 16393 | 16389 (1 row) omm=#
重命名表空间
–命名表空间t_tbspace为app_tbs
ALTER TABLESPACE t_tbspace RENAME TO app_tbs;
omm=# ALTER TABLESPACE t_tbspace RENAME TO app_tbs; ALTER TABLESPACE
–执行下面的gsql命令，查看数据库当前的表空间信息：
\db
omm=# \db List of tablespaces Name | Owner | Location ------------+-------+----------------------- app_tbs | omm | tablespace/t_tbspace1 pg_default | omm | pg_global | omm | (3 rows) omm=#
删除表空间
–用户必须是表空间的owner或者系统管理员才能删除表空间。需要先删除表空间的对象，再删除表空间app_ts：
drop table jack.foo ;
DROP TABLESPACE app_tbs;
omm=# drop table jack.foo ; DROP TABLE omm=# DROP TABLESPACE app_tbs; DROP TABLESPACE omm=#
学习目标
创建表空间t_tbspace、用户test，并使用test，在这个表空间上创建表t1
omm=# CREATE TABLESPACE t_tbspace RELATIVE LOCATION 'tablespace/t_tbspace1'; CREATE TABLESPACE omm=# omm=# CREATE USER test IDENTIFIED BY 'kunpeng@1234'; NOTICE: The encrypted password contains MD5 ciphertext, which is not secure. CREATE ROLE omm=# GRANT CREATE ON TABLESPACE t_tbspace TO test; GRANT omm=# \c omm test Password for user test: Non-SSL connection (SSL connection is recommended when requiring high-security) You are now connected to database "omm" as user "test". omm=> CREATE TABLE t1(i int) TABLESPACE t_tbspace; CREATE TABLE omm=>
查看表空间t_tbspace的oid和大小
omm=# SELECT PG_TABLESPACE_SIZE('t_tbspace'); pg_tablespace_size -------------------- 8192 (1 row) omm=#
查看数据库在默认表空间下有哪些对象
omm=# with objectInDefaultTS as omm-# ( select relname, relkind, relpages,pg_size_pretty(pg_relation_size(a.oid)), omm(# reltablespace,relowner omm(# from pg_class a omm(# where a.relkind in ('r', 'i') and reltablespace='0' omm(# ) omm-# select * omm-# from objectInDefaultTS omm-# where relname not like 'pg_%' and relname not like 'gs_%' and relname not like 'sql_%' omm-# order by relpages desc; relname | relkind | relpages | pg_size_pretty | reltablespace | relowner ------------------------------------------+---------+----------+----------------+---------------+---------- streaming_gather_agg_index | i | 2 | 16 kB | 0 | 10 snapshot_id_key | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_lookupidxid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_schema_change_index | i | 1 | 8192 bytes | 0 | 10 streaming_reaper_status_id_index | i | 1 | 8192 bytes | 0 | 10 streaming_reaper_status_oid_index | i | 1 | 8192 bytes | 0 | 10 snapshot_pkey | i | 1 | 8192 bytes | 0 | 10 statement_history_time_idx | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_defrelid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_id_index | i | 1 | 8192 bytes | 0 | 10 streaming_stream_oid_index | i | 1 | 8192 bytes | 0 | 10 streaming_stream_relid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_relid_index | i | 1 | 8192 bytes | 0 | 10 streaming_cont_query_matrelid_index | i | 1 | 8192 bytes | 0 | 10 plan_table_data | r | 0 | 0 bytes | 0 | 10 streaming_cont_query_oid_index | i | 1 | 8192 bytes | 0 | 10 statement_history | r | 0 | 0 bytes | 0 | 10 streaming_reaper_status | r | 0 | 0 bytes | 0 | 10 streaming_cont_query | r | 0 | 0 bytes | 0 | 10 --More-- streaming_stream | r | 0 | 0 bytes | 0 | 10 snapshot | r | 0 | 0 bytes | 0 | 10 (21 rows) omm=#
查看数据库在非默认表空间下有哪些对象
omm=#select relname,relkind,relpages,pg_size_pretty(pg_relation_size(a.oid)), omm-# reltablespace,relowner omm-# from pg_class a, pg_tablespace tb omm-# where a.relkind in ('r', 'i') omm-# omm-# and tb.spcname='t_tbspace' omm-# and a.reltablespace=tb.oid order by a.relpages desc; relname | relkind | relpages | pg_size_pretty | reltablespace | relowner ---------+---------+----------+----------------+---------------+---------- t1 | r | 0 | 0 bytes | 16401 | 16397 (1 row) omm=#
重命名表空间
omm=# ALTER TABLESPACE t_tbspace RENAME TO app_tbs; ALTER TABLESPACE omm=# \db List of tablespaces Name | Owner | Location ------------+-------+----------------------- app_tbs | omm | tablespace/t_tbspace1 pg_default | omm | pg_global | omm | (3 rows) omm=#
删除表空间
omm=# drop table test.t1 ; DROP TABLE omm=# DROP TABLESPACE app_tbs; DROP TABLESPACE omm=#
课程学习体会
通过这次的实训操作，初步掌握表空间的管理，包括创建表空间、删除表空间、重命名表空间、查看表空间等情况。
