Customize Template

Customize template and other content in database clusters

相关参数

用户可以使用 PG模板 配置项，对集群中的模板数据库 template1 进行定制。

通过这种方式确保任何在该数据库集群中新创建的数据库都带有相同的默认配置：模式，扩展，默认权限。

名称 类型 层级 说明
pg_init string G/C 自定义PG初始化脚本
pg_replication_username string G PG复制用户
pg_replication_password string G PG复制用户的密码
pg_monitor_username string G PG监控用户
pg_monitor_password string G PG监控用户密码
pg_admin_username string G PG管理用户
pg_admin_password string G PG管理用户密码
pg_default_roles role[] G 默认创建的角色与用户
pg_default_privilegs string[] G 数据库默认权限配置
pg_default_schemas string[] G 默认创建的模式
pg_default_extensions extension[] G 默认安装的扩展
pg_hba_rules rule[] G 全局HBA规则
pg_hba_rules_extra rule[] C/I 集群/实例特定的HBA规则
pgbouncer_hba_rules rule[] G/C Pgbouncer全局HBA规则
pgbouncer_hba_rules_extra rule[] G/C Pgbounce特定HBA规则 
^---/pg/bin/pg-init
          |
          ^---(1)--- /pg/tmp/pg-init-roles.sql
          ^---(2)--- /pg/tmp/pg-init-template.sql
          ^---(3)--- <other customize logic in pg-init>

# 业务用户与数据库并不是在模版定制中创建的
^-------------(4)--- /pg/tmp/pg-user-{{ user.name }}.sql
^-------------(5)--- /pg/tmp/pg-db-{{ db.name }}.sql

pg-init

pg-init是用于自定义初始化模板的Shell脚本路径，该脚本将以postgres用户身份，仅在主库上执行，执行时数据库集群主库已经被拉起，可以执行任意Shell命令，或通过psql执行任意SQL命令。

如果不指定该配置项，Pigsty会使用默认的pg-init Shell脚本，如下所示。

#!/usr/bin/env bash
set -uo pipefail


#==================================================================#
#                          Default Roles                           #
#==================================================================#
psql postgres -qAXwtf /pg/tmp/pg-init-roles.sql


#==================================================================#
#                          System Template                         #
#==================================================================#
# system default template
psql template1 -qAXwtf /pg/tmp/pg-init-template.sql

# make postgres same as templated database (optional)
psql postgres  -qAXwtf /pg/tmp/pg-init-template.sql



#==================================================================#
#                          Customize Logic                         #
#==================================================================#
# add your template logic here

如果用户需要执行复杂的定制逻辑，可在该脚本的基础上进行追加。注意pg-init 用于定制数据库集群，通常这是通过修改 模板数据库 实现的。在该脚本执行时，数据库集群已经启动，但业务用户与业务数据库尚未创建。因此模板数据库的修改会反映在默认定义的业务数据库中。

pg-init-roles.sql

在 pg_default_roles 中可以自定义全局统一的角色体系。其中的定义会被渲染为/pg/tmp/pg-init-roles.sql，pg-test集群中的渲染样例如下所示：

```sql ---------------------------------------------------------------------- -- File : pg-init-roles.sql -- Path : /pg/tmp/pg-init-roles -- Time : 2021-03-16 21:24 -- Note : managed by ansible, DO NOT CHANGE -- Desc : creation sql script for default roles ----------------------------------------------------------------------

–###################################################################– – dbrole_readonly – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –no-login’dbrole_readonly'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbrole_readonly.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbrole_readonly” NOLOGIN;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbrole_readonly” NOLOGIN;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbrole_readonly” IS ‘role for global readonly access’;

–==================================================================– – GRANT ROLE – –==================================================================–

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbrole_readonly’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbrole_readwrite – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –no-login’dbrole_readwrite'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbrole_readwrite.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbrole_readwrite” NOLOGIN;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbrole_readwrite” NOLOGIN;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbrole_readwrite” IS ‘role for global read-write access’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “dbrole_readonly” TO “dbrole_readwrite”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbrole_readwrite’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbrole_offline – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –no-login’dbrole_offline'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbrole_offline.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbrole_offline” NOLOGIN;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbrole_offline” NOLOGIN;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbrole_offline” IS ‘role for restricted read-only access (offline instance)';

–==================================================================– – GRANT ROLE – –==================================================================–

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbrole_offline’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbrole_admin – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –no-login’dbrole_admin’; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbrole_admin.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbrole_admin” NOLOGIN BYPASSRLS;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbrole_admin” NOLOGIN BYPASSRLS;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbrole_admin” IS ‘role for object creation’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “dbrole_readwrite” TO “dbrole_admin”; GRANT “pg_monitor” TO “dbrole_admin”; GRANT “pg_signal_backend” TO “dbrole_admin”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbrole_admin’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – postgres – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –superuser’postgres'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-postgres.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “postgres” SUPERUSER;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “postgres” SUPERUSER;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “postgres” IS ‘system superuser’;

–==================================================================– – GRANT ROLE – –==================================================================–

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘postgres’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – replicator – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –replication’replicator'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-replicator.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “replicator” REPLICATION BYPASSRLS;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “replicator” REPLICATION BYPASSRLS;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “replicator” IS ‘system replicator’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “pg_monitor” TO “replicator”; GRANT “dbrole_readonly” TO “replicator”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘replicator’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbuser_monitor – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 ‘dbuser_monitor’; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbuser_monitor.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbuser_monitor” ;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbuser_monitor” ;

– password

– expire

– conn limit ALTER USER “dbuser_monitor” CONNECTION LIMIT 16;

– parameters

– comment COMMENT ON ROLE “dbuser_monitor” IS ‘system monitor user’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “pg_monitor” TO “dbuser_monitor”; GRANT “dbrole_readonly” TO “dbuser_monitor”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbuser_monitor’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbuser_admin – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 –superuser’dbuser_admin'; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbuser_admin.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbuser_admin” SUPERUSER BYPASSRLS;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbuser_admin” SUPERUSER BYPASSRLS;

– password

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbuser_admin” IS ‘system admin user’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “dbrole_admin” TO “dbuser_admin”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbuser_admin’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–###################################################################– – dbuser_stats – –###################################################################– – run as dbsu (postgres by default) – createuser -w -p 5432 ‘dbuser_stats’; – psql -p 5432 -AXtwqf /pg/tmp/pg-user-dbuser_stats.sql

–==================================================================– – CREATE USER – –==================================================================– CREATE USER “dbuser_stats” ;

–==================================================================– – ALTER USER – –==================================================================– – options ALTER USER “dbuser_stats” ;

– password ALTER USER “dbuser_stats” PASSWORD ‘DBUser.Stats’;

– expire

– conn limit

– parameters

– comment COMMENT ON ROLE “dbuser_stats” IS ‘business offline user for offline queries and ETL’;

–==================================================================– – GRANT ROLE – –==================================================================– GRANT “dbrole_offline” TO “dbuser_stats”;

–==================================================================– – PGBOUNCER USER – –==================================================================– – user will not be added to pgbouncer user list by default, – unless pgbouncer is explicitly set to ‘true’, which means production user

– User ‘dbuser_stats’ will NOT be added to /etc/pgbouncer/userlist.txt

–==================================================================–

–==================================================================– – PASSWORD OVERWRITE – –==================================================================– ALTER ROLE “replicator” PASSWORD ‘DBUser.Replicator’; ALTER ROLE “dbuser_monitor” PASSWORD ‘DBUser.Monitor’; ALTER ROLE “dbuser_admin” PASSWORD ‘DBUser.Admin’; –==================================================================–


</details>





## pg-init-template.sql

[`pg-init-template.sql`](https://github.com/Vonng/pigsty/blob/master/roles/postgres/templates/pg-init-template.sql) 是用于初始化 `template1` 数据的脚本模板。PG模板中的变量，大抵都是通过该SQL模板渲染为最终执行的SQL命令。该模板会被渲染至集群主库的`/pg/tmp/pg-init-template.sql`并执行。

Pigsty强烈建议通过提供自定义的`pg-init`脚本完成复杂的定制。如无必要，尽量不要改动`pg-init-template.sql`中的原有逻辑。

​```sql
--==================================================================--
--                           Executions                             --
--==================================================================--
-- psql template1 -AXtwqf /pg/tmp/pg-init-template.sql
-- this sql scripts is responsible for post-init procedure
-- it will
--    * create system users such as replicator, monitor user, admin user
--    * create system default roles
--    * create schema, extensions in template1 & postgres
--    * create monitor views in template1 & postgres


--==================================================================--
--                          Default Privileges                      --
--==================================================================--
{% for priv in pg_default_privileges %}
ALTER DEFAULT PRIVILEGES FOR ROLE {{ pg_dbsu }} {{ priv }};
{% endfor %}

{% for priv in pg_default_privileges %}
ALTER DEFAULT PRIVILEGES FOR ROLE {{ pg_admin_username }} {{ priv }};
{% endfor %}

-- for additional business admin, they can SET ROLE to dbrole_admin
{% for priv in pg_default_privileges %}
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" {{ priv }};
{% endfor %}

--==================================================================--
--                              Schemas                             --
--==================================================================--
{% for schema_name in pg_default_schemas %}
CREATE SCHEMA IF NOT EXISTS "{{ schema_name }}";
{% endfor %}

-- revoke public creation
REVOKE CREATE ON SCHEMA public FROM PUBLIC;

--==================================================================--
--                             Extensions                           --
--==================================================================--
{% for extension in pg_default_extensions %}
CREATE EXTENSION IF NOT EXISTS "{{ extension.name }}"{% if 'schema' in extension %} WITH SCHEMA "{{ extension.schema }}"{% endif %};
{% endfor %}

默认的模板初始化逻辑还会创建监控模式，扩展与相关视图。

```sql --==================================================================-- -- Monitor Views -- --==================================================================--

– cleanse

CREATE SCHEMA IF NOT EXISTS monitor; GRANT USAGE ON SCHEMA monitor TO “{{ pg_monitor_username }}"; GRANT USAGE ON SCHEMA monitor TO “{{ pg_admin_username }}"; GRANT USAGE ON SCHEMA monitor TO “{{ pg_replication_username }}";

DROP VIEW IF EXISTS monitor.pg_table_bloat_human; DROP VIEW IF EXISTS monitor.pg_index_bloat_human; DROP VIEW IF EXISTS monitor.pg_table_bloat; DROP VIEW IF EXISTS monitor.pg_index_bloat; DROP VIEW IF EXISTS monitor.pg_session; DROP VIEW IF EXISTS monitor.pg_kill; DROP VIEW IF EXISTS monitor.pg_cancel; DROP VIEW IF EXISTS monitor.pg_seq_scan;

– Table bloat estimate

CREATE OR REPLACE VIEW monitor.pg_table_bloat AS SELECT CURRENT_CATALOG AS datname, nspname, relname , bs * tblpages AS size, CASE WHEN tblpages - est_tblpages_ff > 0 THEN (tblpages - est_tblpages_ff)/tblpages::FLOAT ELSE 0 END AS ratio FROM ( SELECT ceil( reltuples / ( (bs-page_hdr)fillfactor/(tpl_size100) ) ) + ceil( toasttuples / 4 ) AS est_tblpages_ff, tblpages, fillfactor, bs, tblid, nspname, relname, is_na FROM ( SELECT ( 4 + tpl_hdr_size + tpl_data_size + (2 * ma) - CASE WHEN tpl_hdr_size % ma = 0 THEN ma ELSE tpl_hdr_size % ma END - CASE WHEN ceil(tpl_data_size)::INT % ma = 0 THEN ma ELSE ceil(tpl_data_size)::INT % ma END ) AS tpl_size, (heappages + toastpages) AS tblpages, heappages, toastpages, reltuples, toasttuples, bs, page_hdr, tblid, nspname, relname, fillfactor, is_na FROM ( SELECT tbl.oid AS tblid, ns.nspname , tbl.relname, tbl.reltuples, tbl.relpages AS heappages, coalesce(toast.relpages, 0) AS toastpages, coalesce(toast.reltuples, 0) AS toasttuples, coalesce(substring(array_to_string(tbl.reloptions, ' ‘) FROM ‘fillfactor=([0-9]+)')::smallint, 100) AS fillfactor, current_setting(‘block_size’)::numeric AS bs, CASE WHEN version()~‘mingw32’ OR version()~‘64-bit|x86_64|ppc64|ia64|amd64’ THEN 8 ELSE 4 END AS ma, 24 AS page_hdr, 23 + CASE WHEN MAX(coalesce(s.null_frac,0)) > 0 THEN ( 7 + count(s.attname) ) / 8 ELSE 0::int END + CASE WHEN bool_or(att.attname = ‘oid’ and att.attnum < 0) THEN 4 ELSE 0 END AS tpl_hdr_size, sum( (1-coalesce(s.null_frac, 0)) * coalesce(s.avg_width, 0) ) AS tpl_data_size, bool_or(att.atttypid = ‘pg_catalog.name’::regtype) OR sum(CASE WHEN att.attnum > 0 THEN 1 ELSE 0 END) <> count(s.attname) AS is_na FROM pg_attribute AS att JOIN pg_class AS tbl ON att.attrelid = tbl.oid JOIN pg_namespace AS ns ON ns.oid = tbl.relnamespace LEFT JOIN pg_stats AS s ON s.schemaname=ns.nspname AND s.tablename = tbl.relname AND s.inherited=false AND s.attname=att.attname LEFT JOIN pg_class AS toast ON tbl.reltoastrelid = toast.oid WHERE NOT att.attisdropped AND tbl.relkind = ‘r’ AND nspname NOT IN (‘pg_catalog’,‘information_schema’) GROUP BY 1,2,3,4,5,6,7,8,9,10 ) AS s ) AS s2 ) AS s3 WHERE NOT is_na; COMMENT ON VIEW monitor.pg_table_bloat IS ‘postgres table bloat estimate’;

– Index bloat estimate

CREATE OR REPLACE VIEW monitor.pg_index_bloat AS SELECT CURRENT_CATALOG AS datname, nspname, idxname AS relname, relpages::BIGINT * bs AS size, COALESCE((relpages - ( reltuples * (6 + ma - (CASE WHEN index_tuple_hdr % ma = 0 THEN ma ELSE index_tuple_hdr % ma END) + nulldatawidth + ma - (CASE WHEN nulldatawidth % ma = 0 THEN ma ELSE nulldatawidth % ma END)) / (bs - pagehdr)::FLOAT + 1 )), 0) / relpages::FLOAT AS ratio FROM ( SELECT nspname, idxname, reltuples, relpages, current_setting(‘block_size’)::INTEGER AS bs, (CASE WHEN version() ~ ‘mingw32’ OR version() ~ ‘64-bit|x86_64|ppc64|ia64|amd64’ THEN 8 ELSE 4 END) AS ma, 24 AS pagehdr, (CASE WHEN max(COALESCE(pg_stats.null_frac, 0)) = 0 THEN 2 ELSE 6 END) AS index_tuple_hdr, sum((1.0 - COALESCE(pg_stats.null_frac, 0.0)) * COALESCE(pg_stats.avg_width, 1024))::INTEGER AS nulldatawidth FROM pg_attribute JOIN ( SELECT pg_namespace.nspname, ic.relname AS idxname, ic.reltuples, ic.relpages, pg_index.indrelid, pg_index.indexrelid, tc.relname AS tablename, regexp_split_to_table(pg_index.indkey::TEXT, ' ‘) :: INTEGER AS attnum, pg_index.indexrelid AS index_oid FROM pg_index JOIN pg_class ic ON pg_index.indexrelid = ic.oid JOIN pg_class tc ON pg_index.indrelid = tc.oid JOIN pg_namespace ON pg_namespace.oid = ic.relnamespace JOIN pg_am ON ic.relam = pg_am.oid WHERE pg_am.amname = ‘btree’ AND ic.relpages > 0 AND nspname NOT IN (‘pg_catalog’, ‘information_schema’) ) ind_atts ON pg_attribute.attrelid = ind_atts.indexrelid AND pg_attribute.attnum = ind_atts.attnum JOIN pg_stats ON pg_stats.schemaname = ind_atts.nspname AND ((pg_stats.tablename = ind_atts.tablename AND pg_stats.attname = pg_get_indexdef(pg_attribute.attrelid, pg_attribute.attnum, TRUE)) OR (pg_stats.tablename = ind_atts.idxname AND pg_stats.attname = pg_attribute.attname)) WHERE pg_attribute.attnum > 0 GROUP BY 1, 2, 3, 4, 5, 6 ) est LIMIT 512; COMMENT ON VIEW monitor.pg_index_bloat IS ‘postgres index bloat estimate (btree-only)';

– table bloat pretty

CREATE OR REPLACE VIEW monitor.pg_table_bloat_human AS SELECT nspname || ‘.’ || relname AS name, pg_size_pretty(size) AS size, pg_size_pretty((size * ratio)::BIGINT) AS wasted, round(100 * ratio::NUMERIC, 2) as ratio FROM monitor.pg_table_bloat ORDER BY wasted DESC NULLS LAST; COMMENT ON VIEW monitor.pg_table_bloat_human IS ‘postgres table bloat pretty’;

– index bloat pretty

CREATE OR REPLACE VIEW monitor.pg_index_bloat_human AS SELECT nspname || ‘.’ || relname AS name, pg_size_pretty(size) AS size, pg_size_pretty((size * ratio)::BIGINT) AS wasted, round(100 * ratio::NUMERIC, 2) as ratio FROM monitor.pg_index_bloat; COMMENT ON VIEW monitor.pg_index_bloat_human IS ‘postgres index bloat pretty’;

– pg session

CREATE OR REPLACE VIEW monitor.pg_session AS SELECT coalesce(datname, ‘all’) AS datname, numbackends, active, idle, ixact, max_duration, max_tx_duration, max_conn_duration FROM ( SELECT datname, count() AS numbackends, count() FILTER ( WHERE state = ‘active’ ) AS active, count() FILTER ( WHERE state = ‘idle’ ) AS idle, count() FILTER ( WHERE state = ‘idle in transaction’ OR state = ‘idle in transaction (aborted)’ ) AS ixact, max(extract(epoch from now() - state_change)) FILTER ( WHERE state = ‘active’ ) AS max_duration, max(extract(epoch from now() - xact_start)) AS max_tx_duration, max(extract(epoch from now() - backend_start)) AS max_conn_duration FROM pg_stat_activity WHERE backend_type = ‘client backend’ AND pid <> pg_backend_pid() GROUP BY ROLLUP (1) ORDER BY 1 NULLS FIRST ) t; COMMENT ON VIEW monitor.pg_session IS ‘postgres session stats’;

– pg kill

CREATE OR REPLACE VIEW monitor.pg_kill AS SELECT pid, pg_terminate_backend(pid) AS killed, datname AS dat, usename AS usr, application_name AS app, client_addr AS addr, state, extract(epoch from now() - state_change) AS query_time, extract(epoch from now() - xact_start) AS xact_time, extract(epoch from now() - backend_start) AS conn_time, substring(query, 1, 40) AS query FROM pg_stat_activity WHERE backend_type = ‘client backend’ AND pid <> pg_backend_pid(); COMMENT ON VIEW monitor.pg_kill IS ‘kill all backend session’;

– quick cancel view

DROP VIEW IF EXISTS monitor.pg_cancel; CREATE OR REPLACE VIEW monitor.pg_cancel AS SELECT pid, pg_cancel_backend(pid) AS cancel, datname AS dat, usename AS usr, application_name AS app, client_addr AS addr, state, extract(epoch from now() - state_change) AS query_time, extract(epoch from now() - xact_start) AS xact_time, extract(epoch from now() - backend_start) AS conn_time, substring(query, 1, 40) FROM pg_stat_activity WHERE state = ‘active’ AND backend_type = ‘client backend’ and pid <> pg_backend_pid(); COMMENT ON VIEW monitor.pg_cancel IS ‘cancel backend queries’;

– seq scan

DROP VIEW IF EXISTS monitor.pg_seq_scan; CREATE OR REPLACE VIEW monitor.pg_seq_scan AS SELECT schemaname AS nspname, relname, seq_scan, seq_tup_read, seq_tup_read / seq_scan AS seq_tup_avg, idx_scan, n_live_tup + n_dead_tup AS tuples, n_live_tup / (n_live_tup + n_dead_tup) AS dead_ratio FROM pg_stat_user_tables WHERE seq_scan > 0 and (n_live_tup + n_dead_tup) > 0 ORDER BY seq_tup_read DESC LIMIT 50; COMMENT ON VIEW monitor.pg_seq_scan IS ‘table that have seq scan’;

{% if pg_version >= 13 %}

– pg_shmem auxiliary function – PG 13 ONLY!

CREATE OR REPLACE FUNCTION monitor.pg_shmem() RETURNS SETOF pg_shmem_allocations AS $$ SELECT * FROM pg_shmem_allocations;$$ LANGUAGE SQL SECURITY DEFINER; COMMENT ON FUNCTION monitor.pg_shmem() IS ‘security wrapper for pg_shmem’; {% endif %}

–==================================================================– – Customize Logic – –==================================================================– – This script will be execute on primary instance among a newly created – postgres cluster. it will be executed as dbsu on template1 database – put your own customize logic here – make sure they are idempotent


</details>



一个实际的渲染样例（`pg-test`）如下所示：

<details>


​```sql
----------------------------------------------------------------------
-- File      :   pg-init-template.sql
-- Ctime     :   2018-10-30
-- Mtime     :   2021-02-27
-- Desc      :   init postgres cluster template
-- Path      :   /pg/tmp/pg-init-template.sql
-- Author    :   Vonng(fengruohang@outlook.com)
-- Copyright (C) 2018-2021 Ruohang Feng
----------------------------------------------------------------------


--==================================================================--
--                           Executions                             --
--==================================================================--
-- psql template1 -AXtwqf /pg/tmp/pg-init-template.sql
-- this sql scripts is responsible for post-init procedure
-- it will
--    * create system users such as replicator, monitor user, admin user
--    * create system default roles
--    * create schema, extensions in template1 & postgres
--    * create monitor views in template1 & postgres


--==================================================================--
--                          Default Privileges                      --
--==================================================================--
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT USAGE                         ON SCHEMAS   TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT SELECT                        ON TABLES    TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT SELECT                        ON SEQUENCES TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT EXECUTE                       ON FUNCTIONS TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT USAGE                         ON SCHEMAS   TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT SELECT                        ON TABLES    TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT SELECT                        ON SEQUENCES TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT EXECUTE                       ON FUNCTIONS TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT INSERT, UPDATE, DELETE        ON TABLES    TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT USAGE,  UPDATE                ON SEQUENCES TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT TRUNCATE, REFERENCES, TRIGGER ON TABLES    TO dbrole_admin;
ALTER DEFAULT PRIVILEGES FOR ROLE postgres GRANT CREATE                        ON SCHEMAS   TO dbrole_admin;

ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT USAGE                         ON SCHEMAS   TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT SELECT                        ON TABLES    TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT SELECT                        ON SEQUENCES TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT EXECUTE                       ON FUNCTIONS TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT USAGE                         ON SCHEMAS   TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT SELECT                        ON TABLES    TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT SELECT                        ON SEQUENCES TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT EXECUTE                       ON FUNCTIONS TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT INSERT, UPDATE, DELETE        ON TABLES    TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT USAGE,  UPDATE                ON SEQUENCES TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT TRUNCATE, REFERENCES, TRIGGER ON TABLES    TO dbrole_admin;
ALTER DEFAULT PRIVILEGES FOR ROLE dbuser_admin GRANT CREATE                        ON SCHEMAS   TO dbrole_admin;

-- for additional business admin, they can SET ROLE to dbrole_admin
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT USAGE                         ON SCHEMAS   TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT SELECT                        ON TABLES    TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT SELECT                        ON SEQUENCES TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT EXECUTE                       ON FUNCTIONS TO dbrole_readonly;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT USAGE                         ON SCHEMAS   TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT SELECT                        ON TABLES    TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT SELECT                        ON SEQUENCES TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT EXECUTE                       ON FUNCTIONS TO dbrole_offline;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT INSERT, UPDATE, DELETE        ON TABLES    TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT USAGE,  UPDATE                ON SEQUENCES TO dbrole_readwrite;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT TRUNCATE, REFERENCES, TRIGGER ON TABLES    TO dbrole_admin;
ALTER DEFAULT PRIVILEGES FOR ROLE "dbrole_admin" GRANT CREATE                        ON SCHEMAS   TO dbrole_admin;

--==================================================================--
--                              Schemas                             --
--==================================================================--
CREATE SCHEMA IF NOT EXISTS "monitor";

-- revoke public creation
REVOKE CREATE ON SCHEMA public FROM PUBLIC;

--==================================================================--
--                             Extensions                           --
--==================================================================--
CREATE EXTENSION IF NOT EXISTS "pg_stat_statements" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pgstattuple" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_qualstats" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_buffercache" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pageinspect" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_prewarm" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_visibility" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_freespacemap" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "pg_repack" WITH SCHEMA "monitor";
CREATE EXTENSION IF NOT EXISTS "postgres_fdw";
CREATE EXTENSION IF NOT EXISTS "file_fdw";
CREATE EXTENSION IF NOT EXISTS "btree_gist";
CREATE EXTENSION IF NOT EXISTS "btree_gin";
CREATE EXTENSION IF NOT EXISTS "pg_trgm";
CREATE EXTENSION IF NOT EXISTS "intagg";
CREATE EXTENSION IF NOT EXISTS "intarray";



--==================================================================--
--                            Monitor Views                         --
--==================================================================--

----------------------------------------------------------------------
-- cleanse
----------------------------------------------------------------------
CREATE SCHEMA IF NOT EXISTS monitor;
GRANT USAGE ON SCHEMA monitor TO "dbuser_monitor";
GRANT USAGE ON SCHEMA monitor TO "dbuser_admin";
GRANT USAGE ON SCHEMA monitor TO "replicator";

DROP VIEW IF EXISTS monitor.pg_table_bloat_human;
DROP VIEW IF EXISTS monitor.pg_index_bloat_human;
DROP VIEW IF EXISTS monitor.pg_table_bloat;
DROP VIEW IF EXISTS monitor.pg_index_bloat;
DROP VIEW IF EXISTS monitor.pg_session;
DROP VIEW IF EXISTS monitor.pg_kill;
DROP VIEW IF EXISTS monitor.pg_cancel;
DROP VIEW IF EXISTS monitor.pg_seq_scan;


----------------------------------------------------------------------
-- Table bloat estimate
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_table_bloat AS
    SELECT CURRENT_CATALOG AS datname, nspname, relname , bs * tblpages AS size,
           CASE WHEN tblpages - est_tblpages_ff > 0 THEN (tblpages - est_tblpages_ff)/tblpages::FLOAT ELSE 0 END AS ratio
    FROM (
             SELECT ceil( reltuples / ( (bs-page_hdr)*fillfactor/(tpl_size*100) ) ) + ceil( toasttuples / 4 ) AS est_tblpages_ff,
                    tblpages, fillfactor, bs, tblid, nspname, relname, is_na
             FROM (
                      SELECT
                          ( 4 + tpl_hdr_size + tpl_data_size + (2 * ma)
                              - CASE WHEN tpl_hdr_size % ma = 0 THEN ma ELSE tpl_hdr_size % ma END
                              - CASE WHEN ceil(tpl_data_size)::INT % ma = 0 THEN ma ELSE ceil(tpl_data_size)::INT % ma END
                              ) AS tpl_size, (heappages + toastpages) AS tblpages, heappages,
                          toastpages, reltuples, toasttuples, bs, page_hdr, tblid, nspname, relname, fillfactor, is_na
                      FROM (
                               SELECT
                                   tbl.oid AS tblid, ns.nspname , tbl.relname, tbl.reltuples,
                                   tbl.relpages AS heappages, coalesce(toast.relpages, 0) AS toastpages,
                                   coalesce(toast.reltuples, 0) AS toasttuples,
                                   coalesce(substring(array_to_string(tbl.reloptions, ' ') FROM 'fillfactor=([0-9]+)')::smallint, 100) AS fillfactor,
                                   current_setting('block_size')::numeric AS bs,
                                   CASE WHEN version()~'mingw32' OR version()~'64-bit|x86_64|ppc64|ia64|amd64' THEN 8 ELSE 4 END AS ma,
                                   24 AS page_hdr,
                                   23 + CASE WHEN MAX(coalesce(s.null_frac,0)) > 0 THEN ( 7 + count(s.attname) ) / 8 ELSE 0::int END
                                       + CASE WHEN bool_or(att.attname = 'oid' and att.attnum < 0) THEN 4 ELSE 0 END AS tpl_hdr_size,
                                   sum( (1-coalesce(s.null_frac, 0)) * coalesce(s.avg_width, 0) ) AS tpl_data_size,
                                   bool_or(att.atttypid = 'pg_catalog.name'::regtype)
                                       OR sum(CASE WHEN att.attnum > 0 THEN 1 ELSE 0 END) <> count(s.attname) AS is_na
                               FROM pg_attribute AS att
                                        JOIN pg_class AS tbl ON att.attrelid = tbl.oid
                                        JOIN pg_namespace AS ns ON ns.oid = tbl.relnamespace
                                        LEFT JOIN pg_stats AS s ON s.schemaname=ns.nspname AND s.tablename = tbl.relname AND s.inherited=false AND s.attname=att.attname
                                        LEFT JOIN pg_class AS toast ON tbl.reltoastrelid = toast.oid
                               WHERE NOT att.attisdropped AND tbl.relkind = 'r' AND nspname NOT IN ('pg_catalog','information_schema')
                               GROUP BY 1,2,3,4,5,6,7,8,9,10
                           ) AS s
                  ) AS s2
         ) AS s3
    WHERE NOT is_na;
COMMENT ON VIEW monitor.pg_table_bloat IS 'postgres table bloat estimate';

----------------------------------------------------------------------
-- Index bloat estimate
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_index_bloat AS
    SELECT CURRENT_CATALOG AS datname, nspname, idxname AS relname, relpages::BIGINT * bs AS size,
           COALESCE((relpages - ( reltuples * (6 + ma - (CASE WHEN index_tuple_hdr % ma = 0 THEN ma ELSE index_tuple_hdr % ma END)
                                                   + nulldatawidth + ma - (CASE WHEN nulldatawidth % ma = 0 THEN ma ELSE nulldatawidth % ma END))
                                      / (bs - pagehdr)::FLOAT  + 1 )), 0) / relpages::FLOAT AS ratio
    FROM (
             SELECT nspname,
                    idxname,
                    reltuples,
                    relpages,
                    current_setting('block_size')::INTEGER                                                               AS bs,
                    (CASE WHEN version() ~ 'mingw32' OR version() ~ '64-bit|x86_64|ppc64|ia64|amd64' THEN 8 ELSE 4 END)  AS ma,
                    24                                                                                                   AS pagehdr,
                    (CASE WHEN max(COALESCE(pg_stats.null_frac, 0)) = 0 THEN 2 ELSE 6 END)                               AS index_tuple_hdr,
                    sum((1.0 - COALESCE(pg_stats.null_frac, 0.0)) *
                        COALESCE(pg_stats.avg_width, 1024))::INTEGER                                                     AS nulldatawidth
             FROM pg_attribute
                      JOIN (
                 SELECT pg_namespace.nspname,
                        ic.relname                                                   AS idxname,
                        ic.reltuples,
                        ic.relpages,
                        pg_index.indrelid,
                        pg_index.indexrelid,
                        tc.relname                                                   AS tablename,
                        regexp_split_to_table(pg_index.indkey::TEXT, ' ') :: INTEGER AS attnum,
                        pg_index.indexrelid                                          AS index_oid
                 FROM pg_index
                          JOIN pg_class ic ON pg_index.indexrelid = ic.oid
                          JOIN pg_class tc ON pg_index.indrelid = tc.oid
                          JOIN pg_namespace ON pg_namespace.oid = ic.relnamespace
                          JOIN pg_am ON ic.relam = pg_am.oid
                 WHERE pg_am.amname = 'btree' AND ic.relpages > 0 AND nspname NOT IN ('pg_catalog', 'information_schema')
             ) ind_atts ON pg_attribute.attrelid = ind_atts.indexrelid AND pg_attribute.attnum = ind_atts.attnum
                      JOIN pg_stats ON pg_stats.schemaname = ind_atts.nspname
                 AND ((pg_stats.tablename = ind_atts.tablename AND pg_stats.attname = pg_get_indexdef(pg_attribute.attrelid, pg_attribute.attnum, TRUE))
                     OR (pg_stats.tablename = ind_atts.idxname AND pg_stats.attname = pg_attribute.attname))
             WHERE pg_attribute.attnum > 0
             GROUP BY 1, 2, 3, 4, 5, 6
         ) est
    LIMIT 512;
COMMENT ON VIEW monitor.pg_index_bloat IS 'postgres index bloat estimate (btree-only)';

----------------------------------------------------------------------
-- table bloat pretty
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_table_bloat_human AS
SELECT nspname || '.' || relname AS name,
       pg_size_pretty(size)      AS size,
       pg_size_pretty((size * ratio)::BIGINT) AS wasted,
       round(100 * ratio::NUMERIC, 2)  as ratio
FROM monitor.pg_table_bloat ORDER BY wasted DESC NULLS LAST;
COMMENT ON VIEW monitor.pg_table_bloat_human IS 'postgres table bloat pretty';

----------------------------------------------------------------------
-- index bloat pretty
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_index_bloat_human AS
SELECT nspname || '.' || relname              AS name,
       pg_size_pretty(size)                   AS size,
       pg_size_pretty((size * ratio)::BIGINT) AS wasted,
       round(100 * ratio::NUMERIC, 2)         as ratio
FROM monitor.pg_index_bloat;
COMMENT ON VIEW monitor.pg_index_bloat_human IS 'postgres index bloat pretty';


----------------------------------------------------------------------
-- pg session
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_session AS
SELECT coalesce(datname, 'all') AS datname,
       numbackends,
       active,
       idle,
       ixact,
       max_duration,
       max_tx_duration,
       max_conn_duration
FROM (
         SELECT datname,
                count(*)                                         AS numbackends,
                count(*) FILTER ( WHERE state = 'active' )       AS active,
                count(*) FILTER ( WHERE state = 'idle' )         AS idle,
                count(*) FILTER ( WHERE state = 'idle in transaction'
                    OR state = 'idle in transaction (aborted)' ) AS ixact,
                max(extract(epoch from now() - state_change))
                FILTER ( WHERE state = 'active' )                AS max_duration,
                max(extract(epoch from now() - xact_start))      AS max_tx_duration,
                max(extract(epoch from now() - backend_start))   AS max_conn_duration
         FROM pg_stat_activity
         WHERE backend_type = 'client backend'
           AND pid <> pg_backend_pid()
         GROUP BY ROLLUP (1)
         ORDER BY 1 NULLS FIRST
     ) t;
COMMENT ON VIEW monitor.pg_session IS 'postgres session stats';


----------------------------------------------------------------------
-- pg kill
----------------------------------------------------------------------
CREATE OR REPLACE VIEW monitor.pg_kill AS
SELECT pid,
       pg_terminate_backend(pid)                 AS killed,
       datname                                   AS dat,
       usename                                   AS usr,
       application_name                          AS app,
       client_addr                               AS addr,
       state,
       extract(epoch from now() - state_change)  AS query_time,
       extract(epoch from now() - xact_start)    AS xact_time,
       extract(epoch from now() - backend_start) AS conn_time,
       substring(query, 1, 40)                   AS query
FROM pg_stat_activity
WHERE backend_type = 'client backend'
  AND pid <> pg_backend_pid();
COMMENT ON VIEW monitor.pg_kill IS 'kill all backend session';


----------------------------------------------------------------------
-- quick cancel view
----------------------------------------------------------------------
DROP VIEW IF EXISTS monitor.pg_cancel;
CREATE OR REPLACE VIEW monitor.pg_cancel AS
SELECT pid,
       pg_cancel_backend(pid)                    AS cancel,
       datname                                   AS dat,
       usename                                   AS usr,
       application_name                          AS app,
       client_addr                               AS addr,
       state,
       extract(epoch from now() - state_change)  AS query_time,
       extract(epoch from now() - xact_start)    AS xact_time,
       extract(epoch from now() - backend_start) AS conn_time,
       substring(query, 1, 40)
FROM pg_stat_activity
WHERE state = 'active'
  AND backend_type = 'client backend'
  and pid <> pg_backend_pid();
COMMENT ON VIEW monitor.pg_cancel IS 'cancel backend queries';


----------------------------------------------------------------------
-- seq scan
----------------------------------------------------------------------
DROP VIEW IF EXISTS monitor.pg_seq_scan;
CREATE OR REPLACE VIEW monitor.pg_seq_scan AS
SELECT schemaname                             AS nspname,
       relname,
       seq_scan,
       seq_tup_read,
       seq_tup_read / seq_scan                AS seq_tup_avg,
       idx_scan,
       n_live_tup + n_dead_tup                AS tuples,
       n_live_tup / (n_live_tup + n_dead_tup) AS dead_ratio
FROM pg_stat_user_tables
WHERE seq_scan > 0
  and (n_live_tup + n_dead_tup) > 0
ORDER BY seq_tup_read DESC
LIMIT 50;
COMMENT ON VIEW monitor.pg_seq_scan IS 'table that have seq scan';


----------------------------------------------------------------------
-- pg_shmem auxiliary function
-- PG 13 ONLY!
----------------------------------------------------------------------
CREATE OR REPLACE FUNCTION monitor.pg_shmem() RETURNS SETOF
    pg_shmem_allocations AS $$ SELECT * FROM pg_shmem_allocations;$$ LANGUAGE SQL SECURITY DEFINER;
COMMENT ON FUNCTION monitor.pg_shmem() IS 'security wrapper for pg_shmem';


--==================================================================--
--                          Customize Logic                         --
--==================================================================--
-- This script will be execute on primary instance among a newly created
-- postgres cluster. it will be executed as dbsu on template1 database
-- put your own customize logic here
-- make sure they are idempotent
Last modified 2021-03-28: update en docs (f994b54)