openGauss每日一练第21天
今日目标：
学习检查openGauss数据库运行状态、锁信息、维护表、重建索引等数据库维护操作技术
2.课后作业
2.1 使用操作系统命令和数据库工具检查实例状态
ps -ef |grep gaussdb
– gs_ctl 查看数据目录
gs_ctl notify
– gs_ctl 查看数据库状态
gs_ctl status -D <数据目录>
– gsql 查看参数信息
gsql -r -c “show data_directory;”
root@modb:~# su - omm
omm@modb:~$ ps -ef |grep gaussdb
omm 1 0 0 19:58 ? 00:00:09 gaussdb
omm 559 550 0 20:25 pts/0 00:00:00 grep gaussdb
omm@modb:~$ ps -Tp 1
PID SPID TTY TIME CMD
1 1 ? 00:00:00 gaussdb
1 287 ? 00:00:00 jemalloc_bg_thd
1 293 ? 00:00:00 gaussdb
1 294 ? 00:00:00 syslogger
1 297 ? 00:00:00 reaper
1 295 ? 00:00:00 jemalloc_bg_thd
1 296 ? 00:00:00 alarm
1 298 ? 00:00:00 jemalloc_bg_thd
1 299 ? 00:00:00 jemalloc_bg_thd
1 343 ? 00:00:00 checkpointer
1 344 ? 00:00:00 Spbgwriter
1 345 ? 00:00:00 pagewriter
1 346 ? 00:00:00 pagewriter
1 347 ? 00:00:00 pagewriter
1 349 ? 00:00:00 pagewriter
1 348 ? 00:00:00 pagewriter
1 350 ? 00:00:00 WALwriter
1 351 ? 00:00:00 WALwriteraux
1 352 ? 00:00:00 AVClauncher
1 353 ? 00:00:00 Jobscheduler
1 354 ? 00:00:00 asyncundolaunch
1 355 ? 00:00:00 globalstats
1 356 ? 00:00:00 applylauncher
1 357 ? 00:00:00 statscollector
1 358 ? 00:00:00 percentworker
1 359 ? 00:00:02 ashworker
1 360 ? 00:00:00 TrackStmtWorker
1 361 ? 00:00:00 auditor
1 362 ? 00:00:00 2pccleaner
1 363 ? 00:00:00 faultmonitor
1 364 ? 00:00:00 WLMworker
1 365 ? 00:00:00 WLMmonitor
1 366 ? 00:00:00 WLMarbiter
1 367 ? 00:00:00 undorecycler
omm@modb:~$
-- 查看数据目录
omm@modb:~$ gs_ctl notify
[2022-12-14 20:26:50.627][566][][gs_ctl]: gs_ctl notify ,datadir is /var/lib/opengauss/data
[2022-12-14 20:26:50.627][566][][gs_ctl]: the parameter of notify must be specified
// 查看实例状态
omm@modb:~$ gs_ctl status -D /var/lib/opengauss/data/
[2022-12-14 20:27:02.051][567][][gs_ctl]: gs_ctl status,datadir is /var/lib/opengauss/data
/usr/local/opengauss/bin/gaussdb
gs_ctl: server is running (PID: 1)
omm@modb:~$
-- 使用gsql登录数据库，查看数据目录
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=# show data_directory ;
data_directory
-------------------------
/var/lib/opengauss/data
(1 row)
omm=#
2.2 检查锁信息
--查询数据库中的锁信息
omm=# select * from pg_locks;
locktype | database | relation | page | tuple | bucket | virtualxid | transactionid | classid | objid | objsubid | virtualt
ransaction | pid | sessionid | mode | granted | fastpath | locktag | global_sessionid
------------+----------+----------+------+-------+--------+------------+---------------+---------+-------+----------+---------
-----------+-----------------+-----------------+-----------------+---------+----------+-------------------+------------------
relation | 16384 | 12010 | | | | | | | | | 11/621
| 281471093603568 | 281471093603568 | AccessShareLock | t | t | 4000:2eea:0:0:0:0 | 0:0#0
virtualxid | | | | | | 11/621 | | | | | 11/621
| 281471093603568 | 281471093603568 | ExclusiveLock | t | t | b:26d:0:0:0:7 | 0:0#0
virtualxid | | | | | | 9/398 | | | | | 9/398
| 281471272844528 | 281471272844528 | ExclusiveLock | t | t | 9:18e:0:0:0:7 | 0:0#0
(3 rows)
omm=#
--查询等待锁的线程状态信息
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_eve
nt | locktag | lockmode | block_sessionid | global_sessionid
-----------+---------+-------------+----------+-----+-----------+-------+------------+--------+-------+-------------+---------
---+---------+----------+-----------------+------------------
(0 rows)
omm=#
2.3 查看数据库版本、日志信息
omm=# select version();
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, 64-bit
(1 row)
omm=# select name ,setting from pg_settings where name like 'log_dire%';
name | setting
---------------+---------
log_directory | pg_log
(1 row)
omm=# \! /var/lib/opengauss/data/pg_log
sh: 1: /var/lib/opengauss/data/pg_log: Permission denied
omm=# \! ls /var/lib/opengauss/data/pg_log
postgresql-2022-12-14_195814.log postgresql-2022-12-14_195826.log
omm=# \q
omm@modb:~$ cd /var/lib/opengauss/data/pg_log
omm@modb:/var/lib/opengauss/data/pg_log$ ls
postgresql-2022-12-14_195814.log postgresql-2022-12-14_195826.log
omm@modb:/var/lib/opengauss/data/pg_log$
2.4 检查应用连接数、查看现有最大连接数
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_eve
nt | locktag | lockmode | block_sessionid | global_sessionid
-----------+---------+-------------+----------+-----+-----------+-------+------------+--------+-------+-------------+---------
---+---------+----------+-----------------+------------------
(0 rows)
omm=# SELECT count(*) FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
count
-------
21
(1 row)
omm=# SHOW max_connections;
max_connections
-----------------
200
(1 row)
omm=#
2.5 对表进行VACUUM、VACUUM FULL和ANALYZE操作
为了保证数据库的有效运行，数据库必须在插入/删除操作后，基于客户场景，定期做VACUUM FULL和ANALYZE，更新统计信息，以便获得更优的性能。
VACUUM和ANALYZE会导致I/O流量的大幅增加，这可能会影响其他活动会话的性能。
维护建议
- 定期对部分大表做VACUUM FULL，在性能下降后为全库做VACUUM FULL，目前暂定每月做一次VACUUM FULL。
- 定期对系统表做VACUUM FULL，主要是PG_ATTRIBUTE。
- 启用系统自动清理线程（AUTOVACUUM）自动执行VACUUM和ANALYZE，回收被标识为删除状态的记录空间，并更新表的统计数据
-- 数据准备
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
omm-# (6885, 1, 'Joes', 'Hunter'),
omm-# (4321, 2, 'Lily','Carter'),
omm-# (9527, 3, 'James', 'Cook'),
omm-# (9500, 4, 'Lucy', 'Baker');
INSERT 0 4
omm=# select count(*) from customer_t;
count
-------
4
(1 row)
-- 使用VACUUM，进行磁盘空间回收。
omm=# vacuum customer_t ;
VACUUM
-- 使用VACUUM FULL命令，进行磁盘空间回收。
omm=# vacuum full customer_t ;
VACUUM
-- 执行VACUUM ANALYZE命令进行查询优化。
omm=# vacuum ANALYZE customer_t ;
VACUUM
omm=#
2.6 建表、索引，进行重建索引操作
omm=# CREATE TABLESPACE EXAMPLE RELATIVE LOCATION 'tablespace1/tablespace_1';
CREATE TABLESPACE
omm=# CREATE schema HR;
CREATE SCHEMA
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"
omm=# \di
No relations found.
omm=# set search_path to hr
omm-# ;
SET
omm=# show search_path ;
search_path
-------------
hr
(1 row)
omm=# \di
No relations found.
omm=# CREATE INDEX areaS_idx ON HR.areaS (area_id);
CREATE INDEX
omm=# \di
List of relations
Schema | Name | Type | Owner | Table | Storage
--------+-----------+-------+-------+-------+---------
hr | areas_idx | index | omm | areas |
(1 row)
omm=# REINDEX table HR.areaS;
REINDEX
omm=#
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