第21天-openGauss数据库例行维护
学习目标
学习检查数据库运行状态、锁信息、维护表、重建索引等数据库维护操作技术
课程学习
- 检查openGauss状态
--操作系统命令查看实例状态
su - omm
ps -ef|grep gaussdb
ps -Tp 1
--使用数据库工具gs_ctl查看实例状态
gs_ctl status -D /var/lib/opengauss/data
--检查参数
gsql -r
show data_directory;
- 检查锁信息
锁机制是数据库保证数据一致性的重要手段，检查相关信息可以检查数据库的事务和运行状况。
--查询数据库中的锁信息
SELECT * FROM pg_locks;
--查询等待锁的线程状态信息
SELECT * FROM pg_thread_wait_status WHERE wait_status = 'acquire lock';
- 统计事件数据
SQL语句长时间运行会占用大量系统资源，用户可以通过查看事件发生的时间，占用内存大小来了解现在数据库运行状态。
--查询事件的时间，查询事件的线程启动时间、事务启动时间、SQL启动时间以及状态变更时间。
SELECT backend_start,xact_start,query_start,state_change FROM pg_stat_activity;
--查询当前服务器的会话计数信息
SELECT count(*) FROM pg_stat_activity;
--查询系统级统计信息，查询当前使用内存最多的会话信息。
SELECT * FROM pv_session_memory_detail() ORDER BY usedsize desc limit 10;
--查询表统计信息
SELECT * FROM pg_statistic;
- 数据库版本、日志信息
--数据库版本
SELECT version();
--在gsql中
\! ls /var/lib/opengauss/data/pg_log
\q
--数据库日志位置
cd /var/lib/opengauss/data/pg_log
ls /var/lib/opengauss/data/pg_log
- 检查应用连接数
如果应用程序与数据库的连接数超过最大值，则新的连接无法建立。建议每天检查连接数，及时释放空闲的连接或者增加最大连接数。
--执行如下SQL语句查看连接数。
gsql -r
SELECT count(*) FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
--查看现有最大连接数。
SHOW max_connections;
- 例行维护表：VACUUM、VACUUM FULL和ANALYZE
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。
--创建表、插入数据、查看数据
CREATE TABLE customer_t
( c_customer_sk integer,
c_customer_id char(5),
c_first_name char(6),
c_last_name char(8)
) ;
INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES
(6885, 1, 'Joes', 'Hunter'),
(4321, 2, 'Lily','Carter'),
(9527, 3, 'James', 'Cook'),
(9500, 4, 'Lucy', 'Baker');
select count(*) from customer_t;
--使用VACUUM或VACUUM FULL命令，进行磁盘空间回收。
--使用VACUUM
VACUUM customer_t;
--使用VACUUM full
--需要向正在执行的表增加排他锁，且需要停止其他所有数据库操作。
VACUUM FULL customer_t;
--使用ANALYZE语句更新统计信息。
ANALYZE customer_t;
--使用ANALYZE VERBOSE语句更新统计信息，并输出表的相关信息。
ANALYZE VERBOSE customer_t;
--也可以同时执行VACUUM ANALYZE命令进行查询优化。
VACUUM ANALYZE customer_t;
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。
- 重建索引
在重建索引前，用户可以通过临时增大maintenance_work_mem和psort_work_mem的取值来加快索引的重建。
--环境准备
CREATE TABLESPACE EXAMPLE RELATIVE LOCATION 'tablespace1/tablespace_1';
CREATE schema HR;
CREATE TABLE HR.areaS( area_ID NUMBER, area_NAME VARCHAR2(25) )tablespace EXAMPLE;
\d HR.areaS
CREATE INDEX areaS_idx ON HR.areaS (area_id);
--使用REINDEX TABLE语句重建索引。
REINDEX table HR.areaS;
课程作业
- 使用操作系统命令和数据库工具检查实例状态
#用操作系统命令检查实例状态
omm@modb:~$ ps -ef|grep gaussdb
omm 1 0 0 Dec21 ? 00:24:13 gaussdb
omm 9576 7908 0 14:45 pts/0 00:00:00 grep gaussdb
omm@modb:~$ ps -Tp 1
1 299 ? 00:00:00 gaussdb
PID SPID TTY TIME CMD
1 1 ? 00:00:06 gaussdb
1 293 ? 00:00:00 jemalloc_bg_thd
1 300 ? 00:00:01 syslogger
1 301 ? 00:00:00 jemalloc_bg_thd
1 302 ? 00:00:29 alarm
1 304 ? 00:00:00 jemalloc_bg_thd
1 303 ? 00:00:00 reaper
1 305 ? 00:00:00 jemalloc_bg_thd
1 349 ? 00:00:10 checkpointer
1 350 ? 00:00:00 Spbgwriter
1 351 ? 00:00:02 pagewriter
1 354 ? 00:00:02 pagewriter
1 352 ? 00:00:02 pagewriter
1 353 ? 00:02:50 pagewriter
1 355 ? 00:00:02 pagewriter
1 356 ? 00:00:19 WALwriter
1 357 ? 00:00:00 WALwriteraux
1 358 ? 00:00:01 AVClauncher
1 359 ? 00:00:22 Jobscheduler
1 360 ? 00:00:00 asyncundolaunch
1 361 ? 00:00:04 globalstats
1 362 ? 00:00:00 applylauncher
1 364 ? 00:02:06 percentworker
1 363 ? 00:00:11 statscollector
1 365 ? 00:10:05 ashworker
1 366 ? 00:02:03 TrackStmtWorker
1 367 ? 00:00:04 auditor
1 368 ? 00:00:14 2pccleaner
1 369 ? 00:00:00 faultmonitor
1 370 ? 00:00:04 WLMworker
1 371 ? 00:00:53 WLMmonitor
1 372 ? 00:00:00 WLMarbiter
1 373 ? 00:00:01 undorecycler
#获取数据文件目录
omm@modb:~$ gsql -c "show data_directory"
data_directory
-------------------------
/var/lib/opengauss/data
(1 row)
#使用数据库工具检查实例状态
omm@modb:~$ gs_ctl status -D /var/lib/opengauss/data
[2022-12-25 14:49:14.927][9603][][gs_ctl]: gs_ctl status,datadir is /var/lib/opengauss/data
gs_ctl: server is running (PID: 1)
/usr/local/opengauss/bin/gaussdb
- 检查锁信息
#数据库中的锁信息
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 | | | | | | | | | 11/159182 | 28147130541592
0 | 281471305415920 | AccessShareLock | t | t | 4000:2eea:0:0:0:0 | 0:0#0
virtualxid | | | | | | 11/159182 | | | | | 11/159182 | 28147130541592
0 | 281471305415920 | ExclusiveLock | t | t | b:26dce:0:0:0:7 | 0:0#0
virtualxid | | | | | | 9/70108 | | | | | 9/70108 | 28147147993828
8 | 281471479938288 | ExclusiveLock | t | t | 9:111dc:0:0:0:7 | 0:0#0
(3 rows)
#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_event | locktag | lockmode | b
lock_sessionid | global_sessionid
-----------+---------+-------------+----------+-----+-----------+-------+------------+--------+-------+-------------+------------+---------+----------+--
---------------+------------------
(0 rows)
- 查看数据库版本、日志信息
#查看数据库版本
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)
#日志文件位置
omm=# \! ls /var/lib/opengauss/data/pg_log
postgresql-2022-12-21_132731.log postgresql-2022-12-22_000000.log postgresql-2022-12-24_000000.log
postgresql-2022-12-21_132742.log postgresql-2022-12-23_000000.log postgresql-2022-12-25_000000.log
omm=#
omm@modb:~$ cd /var/lib/opengauss/data/pg_log
omm@modb:/var/lib/opengauss/data/pg_log$ ls
postgresql-2022-12-21_132731.log postgresql-2022-12-22_000000.log postgresql-2022-12-24_000000.log
postgresql-2022-12-21_132742.log postgresql-2022-12-23_000000.log postgresql-2022-12-25_000000.log
- 检查应用连接数、查看现有最大连接数
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.
#查看当前连接数
omm=# SELECT count(*) FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS s;
count
-------
21
(1 row)
#查看现有最大连接数
omm=# show max_connections;
max_connections
-----------------
200
(1 row)
- 对表进行VACUUM、VACUUM FULL和ANALYZE操作
#创建测试表
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-# (9527, 3, 'James', 'Cook'),
omm-# (6885, 1, 'Joes', 'Hunter'),
omm-# (4321, 2, 'Lily','Carter'),
omm-# (9500, 4, 'Lucy', 'Baker');
INSERT 0 4
omm=# select count(*) from customer_t;
omm=# count
-------
4
(1 row)
#指定表 vacuum
omm=# vacuum customer_t ;
VACUUM
#指定表 vacuum full
omm=# vacuum full customer_t ;
VACUUM
#整库vacuum full
omm=# vacuum full
omm-# ;
NOTICE: skipping "pg_type" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_client_global_keys_args" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_authid" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_statistic" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_statistic_ext" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_user_mapping" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_subscription" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_class" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_largeobject" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_attribute" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_proc" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_package" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_partition" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_attrdef" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_constraint" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_inherits" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_index" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_operator" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_opfamily" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_opclass" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_am" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_amop" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_amproc" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_language" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_largeobject_metadata" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_aggregate" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_rewrite" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_trigger" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_description" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_cast" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_enum" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_namespace" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_conversion" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_depend" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_database" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_db_role_setting" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_tablespace" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_pltemplate" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_auth_members" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_shdepend" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_shdescription" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_ts_config" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_ts_config_map" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_ts_dict" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_ts_parser" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_ts_template" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_extension" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_obsscaninfo" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_foreign_data_wrapper" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_foreign_server" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pgxc_class" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pgxc_node" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pgxc_group" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_resource_pool" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_workload_group" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_app_workloadgroup_mapping" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_foreign_table" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_rlspolicy" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_default_acl" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_seclabel" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_shseclabel" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_collation" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_range" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_encrypted_columns" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_column_keys" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_column_keys_args" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_client_global_keys" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_encrypted_proc" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_job" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_asp" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_job_proc" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_object" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_synonym" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_obsscaninfo" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_directory" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_hashbucket" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_global_chain" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_global_config" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "streaming_stream" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_model_warehouse" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_recyclebin" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_txn_snapshot" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_job_argument" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_job_attribute" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_uid" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_db_privilege" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "streaming_cont_query" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "streaming_reaper_status" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_matview" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_matview_dependency" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pgxc_slice" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_opt_model" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_replication_origin" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_publication_rel" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_user_status" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_publication" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_auth_history" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "pg_extension_data_source" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_auditing_policy" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_auditing_policy_privileges" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_auditing_policy_filters" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_auditing_policy_access" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_policy_label" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_masking_policy" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_masking_policy_actions" --- use xc_maintenance_mode to VACUUM FULL it
NOTICE: skipping "gs_masking_policy_filters" --- use xc_maintenance_mode to VACUUM FULL it
VACUUM
#更新表的统计信息，加上verbose，输出表的相关信息
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
#同时执行VACUUM ANALYZE命令进行查询优化
omm=# vacuum ANALYZE customer_t ;
VACUUM
- 建表、索引，进行重建索引操作
#建表空间，建测试表
omm=# create tablespace example relative location 'tablespace/example_tbs1';
CREATE TABLESPACE
omm=# create schema hr;
CREATE SCHEMA
omm=# create table hr.areas(area_ID NUMBER, area_NAME VARCHAR2(25) )tablespace EXAMPLE;
CREATE TABLE
#查询表结构
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
#重建表上的所有索引
omm=# reindex table hr.areas;
REINDEX
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