本文分享自華為雲社群《GaussDB(DWS)的cgroup、資源池、使用者的關係》，作者： nullptr_。
1. 前言
本文主要展示了DWS中cgroup、資源池、使用者之間的關係，從而對DWS的資源設定情況有個初步瞭解。
2. 相關物件建立指令碼
gs_ssh -c "gs_cgroup -cS ClassN1 -G wn1" gs_ssh -c "gs_cgroup -cS ClassN1 -G wn2" gs_ssh -c "gs_cgroup -cS ClassN2 -G wn3" gs_ssh -c "gs_cgroup -cS ClassG1 -G wg1_1" gs_ssh -c "gs_cgroup -cS ClassG1 -G wg1_2" gs_ssh -c "gs_cgroup -cS ClassG2 -G wg2_1" gs_ssh -c "gs_cgroup -cS ClassG2 -G wg2_2" #建立資源池 gsql -d postgres -p 6000 -c "create resource pool respool_1 with (control_group = 'ClassN1:wn1');" gsql -d postgres -p 6000 -c "create resource pool respool_2 with (control_group = 'ClassN1:wn2');" gsql -d postgres -p 6000 -c "create resource pool respool_3 with (control_group = 'ClassN2:wn3');" gsql -d postgres -p 6000 -c "create resource pool respool_4 with (control_group = 'ClassN2:wn3');" gsql -d postgres -p 6000 -c "create resource pool respool_grp_1 with (control_group = 'ClassG1');" gsql -d postgres -p 6000 -c "create resource pool respool_g1_job_1 with (control_group = 'ClassG1:wg1_1');" gsql -d postgres -p 6000 -c "create resource pool respool_g1_job_2 with (control_group = 'ClassG1:wg1_2');" gsql -d postgres -p 6000 -c "create resource pool respool_grp_2 with (control_group = 'ClassG2');" gsql -d postgres -p 6000 -c "create resource pool respool_g2_job_1 with (control_group = 'ClassG2:wg2_1');" gsql -d postgres -p 6000 -c "create resource pool respool_g2_job_2 with (control_group = 'ClassG2:wg2_2');" #建立租戶，建立使用者 gsql -d postgres -p 6000 -c "CREATE USER user_1 RESOURCE POOL 'respool_1' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_2 RESOURCE POOL 'respool_2' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_3 RESOURCE POOL 'respool_3' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_4 PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_5 PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_grp_1 RESOURCE POOL 'respool_grp_1' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_g1_job_1 RESOURCE POOL 'respool_g1_job_1' USER GROUP 'user_grp_1' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_g1_job_2 RESOURCE POOL 'respool_g1_job_2' USER GROUP 'user_grp_1' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_grp_2 RESOURCE POOL 'respool_grp_2' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_g2_job_1 RESOURCE POOL 'respool_g2_job_1' USER GROUP 'user_grp_2' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_g2_job_2 RESOURCE POOL 'respool_g2_job_2' USER GROUP 'user_grp_2' PASSWORD 'Gauss_ab1' ;" gsql -d postgres -p 6000 -c "CREATE USER user_grp_3 RESOURCE POOL 'respool_grp_1' PASSWORD 'Gauss_ab1' ;"
3. cgroup
GaussDB(DWS)資源負載管理的核心是資源池，而配置資源池首先要在環境中實現控制組Cgroups的設定。
Class控制組為資料庫業務執行所在的頂層控制組，叢集部署時會自動生成預設子Class控制組“DefaultClass”。DefaultClass的Medium控制組會含有系統觸發的作業在執行，該控制組不允許進行資源修改，且執行在該控制組上的作業不受資源管理的控制，所以推薦建立新的子Class及其Workload控制組來設定資源比例。
3.1 執行指令碼之後cgroup分佈情況如下
per910mas@xx:~> gs_cgroup -p Top Group information is listed: GID: 0 Type: Top Percent(%): 1000( 50) Name: Root Cores: 0-103 GID: 1 Type: Top Percent(%): 833( 83) Name: Gaussdb:per910mas Cores: 0-103 GID: 2 Type: Top Percent(%): 333( 40) Name: Backend Cores: 0-103 GID: 3 Type: Top Percent(%): 499( 60) Name: Class Cores: 0-103 Backend Group information is listed: GID: 4 Type: BAKWD Name: DefaultBackend TopGID: 2 Percent(%): 266(80) Cores: 0-103 GID: 5 Type: BAKWD Name: Vacuum TopGID: 2 Percent(%): 66(20) Cores: 0-103 Class Group information is listed: GID: 20 Type: CLASS Name: DefaultClass TopGID: 3 Percent(%): 99(20) MaxLevel: 1 RemPCT: 100 Cores: 0-103 GID: 21 Type: CLASS Name: ClassN1 TopGID: 3 Percent(%): 99(20) MaxLevel: 3 RemPCT: 60 Cores: 0-103 GID: 22 Type: CLASS Name: ClassN2 TopGID: 3 Percent(%): 99(20) MaxLevel: 2 RemPCT: 80 Cores: 0-103 GID: 23 Type: CLASS Name: ClassG1 TopGID: 3 Percent(%): 99(20) MaxLevel: 3 RemPCT: 60 Cores: 0-103 GID: 24 Type: CLASS Name: ClassG2 TopGID: 3 Percent(%): 99(20) MaxLevel: 3 RemPCT: 60 Cores: 0-103 Workload Group information is listed: GID: 86 Type: DEFWD Name: wn1:2 ClsGID: 21 Percent(%): 19(20) WDLevel: 2 Cores: 0-103 GID: 87 Type: DEFWD Name: wn2:3 ClsGID: 21 Percent(%): 19(20) WDLevel: 3 Cores: 0-103 GID: 89 Type: DEFWD Name: wn3:2 ClsGID: 22 Percent(%): 19(20) WDLevel: 2 Cores: 0-103 GID: 91 Type: DEFWD Name: wg1_1:2 ClsGID: 23 Percent(%): 19(20) WDLevel: 2 Cores: 0-103 GID: 92 Type: DEFWD Name: wg1_2:3 ClsGID: 23 Percent(%): 19(20) WDLevel: 3 Cores: 0-103 GID: 94 Type: DEFWD Name: wg2_1:2 ClsGID: 24 Percent(%): 19(20) WDLevel: 2 Cores: 0-103 GID: 95 Type: DEFWD Name: wg2_2:3 ClsGID: 24 Percent(%): 19(20) WDLevel: 3 Cores: 0-103 CM Group information is listed: Timeshare Group information is listed: GID: 724 Type: TSWD Name: Low Rate: 1 GID: 725 Type: TSWD Name: Medium Rate: 2 GID: 726 Type: TSWD Name: High Rate: 4 GID: 727 Type: TSWD Name: Rush Rate: 8
系統資源限制分為配額和限額。預設情況下為配額
- 配額：配額是一種比較靈活的控制方式，例如
wn1:2的配額為20%，在正常情況下組內資源使用可以超過20%，如果在資源繁忙的情況下（使用率為100%）則資源嚴格按照配額的大小進行限制 - 限額：限額則直接限制CPU使用的核數的範圍。
- 配額&限額：則在CPU核數範圍內限制配額比例
4. 資源池
4.1 資源池分佈情況如下
postgres=# select oid,* from pg_resource_pool; oid | respool_name | mem_percent | cpu_affinity | control_group | active_statements | max_dop | memory_limit | parentid | io_limits | io_priority | nodegroup | is_foreign | short_acc | except_rule | weight ------------+------------------+-------------+--------------+---------------------+-------------------+---------+--------------+------------+-----------+-------------+--------------+------------+-----------+-------------+-------- 10 | default_pool | 0 | -1 | DefaultClass:Medium | -1 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585814 | respool_1 | 0 | -1 | ClassN1:wn1 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585815 | respool_2 | 0 | -1 | ClassN1:wn2 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585816 | respool_3 | 0 | -1 | ClassN2:wn3 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585817 | respool_grp_1 | 20 | -1 | ClassG1 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585818 | respool_g1_job_1 | 20 | -1 | ClassG1:wg1_1 | 10 | -1 | default | 2147585817 | 0 | None | installation | f | t | None | -1 2147585819 | respool_g1_job_2 | 20 | -1 | ClassG1:wg1_2 | 10 | -1 | default | 2147585817 | 0 | None | installation | f | t | None | -1 2147585820 | respool_grp_2 | 20 | -1 | ClassG2 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 2147585821 | respool_g2_job_1 | 20 | -1 | ClassG2:wg2_1 | 10 | -1 | default | 2147585820 | 0 | None | installation | f | t | None | -1 2147585822 | respool_g2_job_2 | 20 | -1 | ClassG2:wg2_2 | 10 | -1 | default | 2147585820 | 0 | None | installation | f | t | None | -1 2147586195 | respool_4 | 0 | -1 | ClassN2:wn3 | 10 | -1 | default | 0 | 0 | None | installation | f | t | None | -1 (11 rows)
4.1.1 組資源池限制
per910mas@xx:~> gsql -d postgres -p 6000 -c "create resource pool respool_grp_3 with (control_group = 'ClassG1');" ERROR: resource pool with control_group ClassG1 has been existed in the two-layer resource pool list
4.1.2 業務資源池
資源池的記憶體資源計算mem_percent需要按照層級進行比例計算
4.1.3 預設資源池
如果開啟了資源管理功能，則系統會預設建立一個資源池default_pool。當一個會話或者使用者沒有指定關聯的資源池時，都會被預設關聯到default_pool。default_pool預設繫結DefaultClass:Medium控制組，同時併發和記憶體預設不管控，default_pool支援引數修改，但關聯default_pool的作業會受到max_active_statements全域性併發限制。當管理員執行運維操作不需要進行管控時，需要在執行SQL前執行SET session_respool=‘root’;將資源池切換至運維佇列，此時作業將不受控。
5. 使用者
5.1 使用者分佈情況
postgres=# select * from pg_user;、 usename | usesysid | usecreatedb | usesuper | usecatupd | userepl | passwd | valbegin | valuntil | respool | parent | spacelimit | useconfig | nodegroup | tempspacelimit | spillspacelimit ---------------+------------+-------------+----------+-----------+---------+----------+----------+----------+------------------+------------+------------+-----------+-----------+----------------+----------------- per910mas | 10 | t | t | t | t | ******** | | | default_pool | 0 | | | | | u1 | 2147558961 | f | f | f | f | ******** | | | default_pool | 0 | | | | | user_1 | 2147585823 | f | f | f | f | ******** | | | respool_1 | 0 | | | | | user_2 | 2147585827 | f | f | f | f | ******** | | | respool_2 | 0 | | | | | user_3 | 2147585831 | f | f | f | f | ******** | | | respool_3 | 0 | | | | | user_4 | 2147585835 | f | f | f | f | ******** | | | default_pool | 0 | | | | | user_5 | 2147585839 | f | f | f | f | ******** | | | default_pool | 0 | | | | | user_grp_1 | 2147585843 | f | f | f | f | ******** | | | respool_grp_1 | 0 | | | | | user_g1_job_1 | 2147585847 | f | f | f | f | ******** | | | respool_g1_job_1 | 2147585843 | | | | | user_g1_job_2 | 2147585851 | f | f | f | f | ******** | | | respool_g1_job_2 | 2147585843 | | | | | user_grp_2 | 2147585855 | f | f | f | f | ******** | | | respool_grp_2 | 0 | | | | | user_g2_job_1 | 2147585859 | f | f | f | f | ******** | | | respool_g2_job_1 | 2147585855 | | | | | user_g2_job_2 | 2147585863 | f | f | f | f | ******** | | | respool_g2_job_2 | 2147585855 | | | | | user_grp_3 | 2147586254 | f | f | f | f | ******** | | | respool_grp_1 | 0 | | | | | (14 rows)
5.1.2 多租戶場景
- 業務使用者共享組使用者的資源，組使用者共享其所在資源池的資源。
- 業務使用者必須掛在到組使用者下，且層級必須與資源池層級一一對應
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