fix(pgsql): handle PostgreSQL list-type GUC parameters correctly (#689)

PostgreSQL has certain GUC parameters that accept comma-separated lists
(marked with GUC_LIST_INPUT flag). These parameters must NOT have their
entire value wrapped in quotes, otherwise PostgreSQL treats the whole
string as a single value rather than parsing it as a comma-separated list.

Problem:
  In v4.0.0, the parameter templates were changed to quote all values:
    ALTER USER "x" SET "search_path" = '"$user", public';  -- WRONG
  This causes search_path to be stored as ONE string instead of a list.

Solution:
  Use a whitelist approach to identify list-type parameters and render
  them without outer quotes:
    ALTER USER "x" SET "search_path" = "$user", public;   -- CORRECT

Affected parameters by context level:

  User/Role level (pg-user.sql, pg-init-roles.sql):
    - search_path
    - temp_tablespaces
    - local_preload_libraries
    - session_preload_libraries

  Database level (pg-db.sql):
    - Above parameters plus log_destination

  Instance level (patroni.yml -> postgresql.auto.conf):
    - Above parameters plus:
    - shared_preload_libraries
    - unix_socket_directories
    - debug_io_direct

Also adds missing condition for pg_watchdog task to skip when
patroni_watchdog_mode is set to 'off'.

Fixes: #689

Author: Vonng

roles/pgsql/tasks/patroni.yml

@@ -6,6 +6,7 @@
 - name: grant postgres dbsu watchdog owner
   tags: pg_watchdog
   ignore_errors: true
+  when: patroni_watchdog_mode != 'off'
   file: path=/dev/watchdog owner={{ pg_dbsu }} group=postgres
 
 
@@ -63,8 +64,13 @@
         content: |
           # Do not edit this file or use ALTER SYSTEM manually!
           # It is managed by Pigsty & Ansible automatically!
+          {% set list_params = ['search_path', 'temp_tablespaces', 'local_preload_libraries', 'session_preload_libraries', 'log_destination', 'shared_preload_libraries', 'unix_socket_directories', 'debug_io_direct'] %}
           {% for key, value in pg_parameters.items() %}
+          {% if key in list_params %}
+          {{ key }} = {{ value }}
+          {% else %}
           {{ key }} = '{{ value }}'
+          {% endif %}
           {% endfor %}
 
     - name: restart postgres via patroni
@@ -216,8 +222,13 @@
     content: |
       # Do not edit this file or use ALTER SYSTEM manually!
       # It is managed by Pigsty & Ansible automatically!
+      {% set list_params = ['search_path', 'temp_tablespaces', 'local_preload_libraries', 'session_preload_libraries', 'log_destination', 'shared_preload_libraries', 'unix_socket_directories', 'debug_io_direct'] %}
       {% for key, value in pg_parameters.items() %}
+      {% if key in list_params %}
+      {{ key }} = {{ value }}
+      {% else %}
       {{ key }} = '{{ value }}'
+      {% endif %}
       {% endfor %}
 
 

roles/pgsql/templates/pg-db.sql

@@ -80,10 +80,13 @@ ALTER DATABASE "{{ database.name }}" IS_TEMPLATE {{ database.is_template|lower }
 
 -- parameters
 {% if 'parameters' in database and database.parameters is not none %}
+{% set list_params = ['search_path', 'temp_tablespaces', 'local_preload_libraries', 'session_preload_libraries', 'log_destination'] %}
 {% for key, value in database.parameters.items() %}
 {% if value is not none %}
 {% if value | string | upper == 'DEFAULT' %}
 ALTER DATABASE "{{ database.name }}" SET "{{ key }}" = DEFAULT;
+{% elif key in list_params %}
+ALTER DATABASE "{{ database.name }}" SET "{{ key }}" = {{ value }};
 {% else %}
 ALTER DATABASE "{{ database.name }}" SET "{{ key }}" = '{{ value | replace("'", "''") }}';
 {% endif %}

roles/pgsql/templates/pg-init-roles.sql

@@ -75,10 +75,13 @@ ALTER USER "{{ user.name }}" CONNECTION LIMIT {{ user.connlimit | int }};
 
 -- parameters
 {% if 'parameters' in user and user.parameters is not none and user.parameters|length > 0 %}
+{% set list_params = ['search_path', 'temp_tablespaces', 'local_preload_libraries', 'session_preload_libraries'] %}
 {% for key, value in user.parameters.items() %}
 {% if value is not none %}
 {% if value | string | upper == 'DEFAULT' %}
 ALTER USER "{{ user.name }}" SET "{{ key }}" = DEFAULT;
+{% elif key in list_params %}
+ALTER USER "{{ user.name }}" SET "{{ key }}" = {{ value }};
 {% else %}
 ALTER USER "{{ user.name }}" SET "{{ key }}" = '{{ value | replace("'", "''") }}';
 {% endif %}

roles/pgsql/templates/pg-user.sql

@@ -80,10 +80,13 @@ ALTER USER "{{ user.name }}" CONNECTION LIMIT {{ user.connlimit | int }};
 
 -- parameters
 {% if 'parameters' in user and user.parameters is not none and user.parameters|length > 0 %}
+{% set list_params = ['search_path', 'temp_tablespaces', 'local_preload_libraries', 'session_preload_libraries'] %}
 {% for key, value in user.parameters.items() %}
 {% if value is not none %}
 {% if value | string | upper == 'DEFAULT' %}
 ALTER USER "{{ user.name }}" SET "{{ key }}" = DEFAULT;
+{% elif key in list_params %}
+ALTER USER "{{ user.name }}" SET "{{ key }}" = {{ value }};
 {% else %}
 ALTER USER "{{ user.name }}" SET "{{ key }}" = '{{ value | replace("'", "''") }}';
 {% endif %}