openGauss每日一练第21天

数据库例行维护

1、使用操作系统命令和数据库工具检查实例状态

--操作系统命令查看进程
omm@modb:~$ ps -ef|grep gaussdb
omm          1     0  0 09:51 ?        00:00:05 gaussdb
omm        495   488  0 10:08 pts/0    00:00:00 grep gaussdb


root@modb:~# ps -Tp 1
  PID  SPID TTY          TIME CMD
    1     1 ?        00:00:00 gaussdb
    1   297 ?        00:00:00 jemalloc_bg_thd
    1   303 ?        00:00:00 gaussdb
    1   304 ?        00:00:00 syslogger
    1   305 ?        00:00:00 jemalloc_bg_thd
    1   306 ?        00:00:00 alarm
    1   307 ?        00:00:00 reaper
    1   308 ?        00:00:00 jemalloc_bg_thd
    1   309 ?        00:00:00 jemalloc_bg_thd
    1   353 ?        00:00:00 checkpointer
    1   354 ?        00:00:00 Spbgwriter
    1   355 ?        00:00:00 pagewriter
    1   356 ?        00:00:00 pagewriter

---数据库工具查看实例状态
omm@modb:~$ gs_ctl status -D /var/lib/opengauss/data
[2022-12-14 10:11:06.529][525][][gs_ctl]: gs_ctl status,datadir is /var/lib/opengauss/data 
gs_ctl: server is running (PID: 1)
/usr/local/opengauss/bin/gaussdb


gsql -r
show data_directory;
omm=# show data_directory;
     data_directory      
-------------------------
 /var/lib/opengauss/data
(1 row)

2、检查锁信息

--查看锁信息
omm=#  SELECT * FROM pg_locks;
  locktype  | database | relation | page | tuple | bucket | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction |       
pid       |    sessionid    |      mode       | granted | fastpath |      locktag      | global_sessionid 
------------+----------+----------+------+-------+--------+------------+---------------+---------+-------+----------+--------------------+-------
----------+-----------------+-----------------+---------+----------+-------------------+------------------
 relation   |    16384 |    12010 |      |       |        |            |               |         |       |          | 11/423             | 281471
264521456 | 281471264521456 | AccessShareLock | t       | t        | 4000:2eea:0:0:0:0 | 0:0#0
 virtualxid |          |          |      |       |        | 11/423     |               |         |       |          | 11/423             | 281471
264521456 | 281471264521456 | ExclusiveLock   | t       | t        | b:1a7:0:0:0:7     | 0:0#0
 virtualxid |          |          |      |       |        | 8/365      |               |         |       |          | 8/365              | 281471
484722416 | 281471484722416 | ExclusiveLock   | t       | t        | 8:16d:0:0:0:7     | 0:0#0
(3 rows)

--查看锁等待信息
 omm=#  SELECT * FROM pg_thread_wait_status WHERE wait_status = 'acquire lock';

 node_name | db_name | thread_name | query_id | tid | sessionid | lwtid | psessionid | tlevel | smpid | wait_status | wait_event | locktag | lock
mode | block_sessionid | global_sessionid 
-----------+---------+-------------+----------+-----+-----------+-------+------------+--------+-------+-------------+------------+---------+-----
-----+-----------------+------------------
(0 rows)

3、查看数据库版本、日志信息

--查看数据库版本
omm=# select version()
omm-# ;
                                                                        version                                                                  
      
-------------------------------------------------------------------------------------------------------------------------------------------------
------
 (openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr   on aarch64-unknown-linux-gnu, compiled by g++ (GCC) 7.3.0, 6
4-bit
(1 row)


--查看数据库日志信息
omm=# \! ls /var/lib/opengauss/data/pg_log
postgresql-2022-12-14_095200.log  postgresql-2022-12-14_095211.log

\q

cd /var/lib/opengauss/data/pg_log
ls /var/lib/opengauss/data/pg_log

omm@modb:~$ cd /var/lib/opengauss/data/pg_log
omm@modb:/var/lib/opengauss/data/pg_log$ ls -lrt 
total 100
-rw------- 1 omm omm 26124 Dec 14 09:52 postgresql-2022-12-14_095200.log
-rw------- 1 omm omm 66923 Dec 14 10:30 postgresql-2022-12-14_095211.log

4、检查应用连接数、查看现有最大连接数

--查看连接数
omm=# SELECT count(*) FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
 count 
-------
    21
(1 row)

--查看最大连接数
omm=# SHOW max_connections;
 max_connections 
-----------------
 200
(1 row)

5、对表进行VACUUM、VACUUM FULL和ANALYZE操作

--创建环境
omm=# CREATE TABLE customer_t
omm-# (  c_customer_sk             integer,   
omm(#   c_customer_id             char(5),    
omm(#   c_first_name              char(6),    
omm(#   c_last_name               char(8) 
omm(# ) ;
CREATE TABLE
omm=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES    
(6885, 1, 'Joes', 'Hunter'),    
omm-# omm-# (4321, 2, 'Lily','Carter'),    
omm-# omm-# (9527, 3, 'James', 'Cook'),
(9500, 4, 'Lucy', 'Baker');
INSERT 0 4
omm=# select count(*) from customer_t;
 count 
-------
     4
(1 row)

--VACUUM表
omm=# VACUUM customer_t;
VACUUM

--VACUUM ALL表
omm=# VACUUM FULL customer_t;
VACUUM

--ANALYZE 表
omm=# ANALYZE VERBOSE customer_t;
INFO:  analyzing "public.customer_t"(gaussdb pid=1)
INFO:  ANALYZE INFO : "customer_t": scanned 1 of 1 pages, containing 4 live rows and 0 dead rows; 4 rows in sample, 4 estimated total rows(gaussdb pid=1)
ANALYZE

--同时vacuum和analyze
omm=# VACUUM ANALYZE customer_t;
VACUUM

6、建表、索引，进行重建索引操作

--建表
omm=# CREATE TABLESPACE EXAMPLE RELATIVE LOCATION 'tablespace1/tablespace_1';
CREATE TABLESPACE

--创建schema
omm=# CREATE schema HR;
CREATE SCHEMA

--建表
omm=# CREATE TABLE HR.areaS(   area_ID NUMBER,   area_NAME VARCHAR2(25)  )tablespace EXAMPLE;
CREATE TABLE

omm=# \d HR.areaS
               Table "hr.areas"
  Column   |         Type          | Modifiers 
-----------+-----------------------+-----------
 area_id   | numeric               | 
 area_name | character varying(25) | 
Tablespace: "example"

--建索引
omm=# CREATE INDEX areaS_idx ON HR.areaS (area_id);
CREATE INDEX
omm=# 

--索引重建
omm=# REINDEX  table HR.areaS;
REINDEX
omm=#