Analyze a PostgreSQL database (optimizer statistics) immediately after the upgrade

pg_upgrade.yml

@@ -56,7 +56,7 @@
   tags:
     - always
 
-- name: "(1/7) PRE-UPGRADE: Perform Pre-Checks"
+- name: "(1/6) PRE-UPGRADE: Perform Pre-Checks"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -79,7 +79,7 @@
     - upgrade
     - pre-checks
 
-- name: "(2/7) PRE-UPGRADE: Install new PostgreSQL packages"
+- name: "(2/6) PRE-UPGRADE: Install new PostgreSQL packages"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -103,7 +103,7 @@
     - upgrade-check
     - packages
 
-- name: "(3/7) PRE-UPGRADE: Initialize new db, schema compatibility check, and pg_upgrade --check"
+- name: "(3/6) PRE-UPGRADE: Initialize new db, schema compatibility check, and pg_upgrade --check"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -143,7 +143,7 @@
     - upgrade-check
     - schema-compatibility-check
 
-- name: "(4/7) PRE-UPGRADE: Prepare the Patroni configuration"
+- name: "(4/6) PRE-UPGRADE: Prepare the Patroni configuration"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -165,7 +165,7 @@
     - upgrade
     - update-config
 
-- name: "(5/7) UPGRADE: Upgrade PostgreSQL"
+- name: "(5/6) UPGRADE: Upgrade PostgreSQL"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -228,7 +228,7 @@
   tags:
     - upgrade
 
-- name: "(6/7) POST-UPGRADE: Perform Post-Checks and Update extensions"
+- name: "(6/6) POST-UPGRADE: Analyze a PostgreSQL database (update optimizer statistics) and Post-Upgrade tasks"
   hosts: 'primary:secondary'
   gather_facts: false
   become: true
@@ -242,39 +242,23 @@
     - name: Include upgrade variables
       ansible.builtin.include_vars: "vars/upgrade.yml"
   tasks:
-    - name: Running Post-Checks
+    - name: Analyze database
       ansible.builtin.include_role:
         name: upgrade
-        tasks_from: post_checks
+        tasks_from: statistics
+      tags: analyze, statistics
 
     - name: Update extensions
       ansible.builtin.include_role:
         name: upgrade
         tasks_from: extensions
       when: update_extensions | bool
-  tags:
-    - upgrade
-    - post-checks
-    - update-extensions
+      tags: update_extensions
 
-- name: "(7/7) POST-UPGRADE: Analyze a PostgreSQL database (update optimizer statistics) and Post-Upgrade tasks"
-  hosts: 'primary:secondary'
-  gather_facts: false
-  become: true
-  become_user: postgres
-  any_errors_fatal: true
-  pre_tasks:
-    - name: Include main variables
-      ansible.builtin.include_vars: "vars/main.yml"
-    - name: Include OS-specific variables
-      ansible.builtin.include_vars: "vars/{{ ansible_os_family }}.yml"
-    - name: Include upgrade variables
-      ansible.builtin.include_vars: "vars/upgrade.yml"
-  tasks:
-    - name: Analyze database
+    - name: Running Post-Checks
       ansible.builtin.include_role:
         name: upgrade
-        tasks_from: statistics
+        tasks_from: post_checks
 
     - name: Running Post-Upgrade tasks
       ansible.builtin.include_role:
@@ -283,7 +267,5 @@
   tags:
     - upgrade
     - post-upgrade
-    - analyze
-    - statistics
 
 ...

roles/upgrade/README.md

@@ -77,6 +77,7 @@ If these checks pass, the playbook switches back to the old PostgreSQL paths and
 | `schema_compatibility_check_timeout` | Max duration for compatibility check (pg_dumpall --schema-only) in seconds. | `3600` |
 | `vacuumdb_parallel_jobs` | Execute the analyze command in parallel by running `njobs` commands simultaneously. This option may reduce the processing time but it also increases the load on the database server. | all CPU cores |
 | `vacuumdb_analyze_timeout` | Max duration of analyze command in seconds. | `3600` |
+| `vacuumdb_analyze_terminate_treshold` | Terminate active queries that are longer than the specified time (in seconds) during the collection of statistics (0 = do not terminate active backends). | `0` |
 | `update_extensions` | Automatically update all PostgreSQL extensions. | `true` |
 | `max_replication_lag_bytes` | Maximum allowed replication lag in bytes. | `10485760` |
 | `max_transaction_sec` | Maximum allowed duration for a transaction in seconds. | `15` |
@@ -285,20 +286,10 @@ Please see the variable file vars/[upgrade.yml](../../vars/upgrade.yml)
   - Start vip-manager service
   - Make sure that the cluster ip address (VIP) is running
 
-#### 6. POST-UPGRADE: Perform Post-Checks and Update extensions
-- **Make sure that physical replication is active**
-  - if no active replication connections found, print error message:
-    - "No active replication connections found. Please check the replication status and PostgreSQL logs."
-- **Create a table "test_replication" with 10000 rows on the Primary**
-- **Wait until the PostgreSQL replica is synchronized**
-  - Notes: max wait time: 2 minutes
-- **Drop a table "test_replication"**
-- **Print the result of checking the number of records**
-  - if the number of rows match, print info message:
-    - "The PostgreSQL Replication is OK. The number of records in the 'test_replication' table the same as the Primary."
-  - if the number of rows does not match, print error message:
-    - "The number of records in the 'test_replication' table does not match the Primary. Please check the replication status and PostgreSQL logs."
-- **Get a list of databases**
+#### 6. POST-UPGRADE: Analyze a PostgreSQL database (update optimizer statistics) and Post-Upgrade tasks
+- **Run vacuumdb to analyze the PostgreSQL databases**
+  - Note: Uses parallel processes equal to 50% of CPU cores ('`vacuumdb_parallel_jobs`' variable)
+  - Note: Before collecting statistics, the 'pg_terminator' script is launched to monitor and terminate any 'ANALYZE' blockers. Once statistics collection is complete, the script is stopped.
 - **Update extensions in each database**
   - Get list of installed PostgreSQL extensions
   - Get list of old PostgreSQL extensions
@@ -310,33 +301,38 @@ Please see the variable file vars/[upgrade.yml](../../vars/upgrade.yml)
       - Notes: if pg_repack is installed
     - Notes: if there are no old extensions, print message:
       - "The extension versions are up-to-date for the database. No update is required."
-
-#### 7. POST-UPGRADE: Analyze a PostgreSQL database (update optimizer statistics) and Post-Upgrade tasks
-- **Run vacuumdb to analyze the PostgreSQL databases**
-  - Notes: Uses parallel processes equal to CPU cores ('`vacuumdb_parallel_jobs`' variable)
-  - Notes: Before collecting statistics, the 'pg_terminator' script is launched to monitor and terminate any 'ANALYZE' blockers. Once statistics collection is complete, the script is stopped.
-  - Wait for the analyze to complete.
-    - Notes: max wait time: 1 hour ('`vacuumdb_analyze_timeout`' variable)
-- **Ensure the current data directory is the new data directory**
-  - Notes: to prevent deletion the old directory if it is used
-- **Delete the old PostgreSQL data directory**
-  - Notes: perform pg_dropcluster for Debian based
-- **Delete the old PostgreSQL WAL directory**
-  - Notes: if 'pg_new_wal_dir' is defined
-- **Remove old PostgreSQL packages**
-  - Notes: if 'pg_old_packages_remove' is 'true'
-- **pgBackRest** (if 'pgbackrest_install' is 'true')
-  - Check pg-path option
-  - Update pg-path in pgbackrest.conf
-  - Upgrade stanza
-- **WAL-G** (if 'wal_g_install' is 'true')
-  - Update PostgreSQL data directory path in .walg.json
-  - Update PostgreSQL data directory path in cron jobs
-- **Check the Patroni cluster state**
-- **Check the current PostgreSQL version**
-- **Remove temporary local access rule from pg_hba.conf**
-  - Notes: if it has been changed
-  - Update the PostgreSQL configuration
-- **Print info messages**
-  - List the Patroni cluster members
-  - Upgrade completed
+- **Perform Post-Checks**
+    - Make sure that physical replication is active
+      - Note: if no active replication connections found, print error message: "No active replication connections found. Please check the replication status and PostgreSQL logs."
+      - Create a table "test_replication" with 10000 rows on the Primary
+      - Wait until the PostgreSQL replica is synchronized (max wait time: 2 minutes)
+      - Drop a table "test_replication"
+      - Print the result of checking the number of records
+      - if the number of rows match, print info message: "The PostgreSQL Replication is OK. The number of records in the 'test_replication' table the same as the Primary."
+      - if the number of rows does not match, print error message: "The number of records in the 'test_replication' table does not match the Primary. Please check the replication status and PostgreSQL logs."
+- **Perform Post-Upgrade tasks**
+    - **Ensure the current data directory is the new data directory**
+      - Notes: to prevent deletion the old directory if it is used
+    - **Delete the old PostgreSQL data directory**
+      - Notes: perform pg_dropcluster for Debian based
+    - **Delete the old PostgreSQL WAL directory**
+      - Notes: if 'pg_new_wal_dir' is defined
+    - **Remove old PostgreSQL packages**
+      - Notes: if 'pg_old_packages_remove' is 'true'
+    - **Remove temporary local access rule from pg_hba.conf**
+      - Notes: if it has been changed
+      - Update the PostgreSQL configuration
+    - **pgBackRest** (if 'pgbackrest_install' is 'true')
+      - Check pg-path option
+      - Update pg-path in pgbackrest.conf
+      - Upgrade stanza
+    - **WAL-G** (if 'wal_g_install' is 'true')
+      - Update PostgreSQL data directory path in .walg.json
+      - Update PostgreSQL data directory path in cron jobs
+    - **Wait for the analyze to complete.**
+      - Notes: max wait time: 1 hour ('`vacuumdb_analyze_timeout`' variable)
+    - **Check the Patroni cluster state**
+    - **Check the current PostgreSQL version**
+    - **Print info messages**
+      - List the Patroni cluster members
+      - Upgrade completed

roles/upgrade/tasks/post_upgrade.yml

@@ -71,7 +71,21 @@
     - pg_old_packages_remove | bool
     - ansible_os_family == "Debian"
 
-# pgbackrest (local)
+# Return the pg_hba.conf file to its original state (if it has been changed)
+- block:
+    - name: Remove temporary local access rule from pg_hba.conf
+      ansible.builtin.blockinfile:
+        path: "{{ pg_new_confdir }}/pg_hba.conf"
+        marker: "# {mark} ANSIBLE TEMPORARY pg_upgrade RULE"
+        state: absent
+
+    - name: Update the PostgreSQL configuration
+      ansible.builtin.command: "{{ pg_new_bindir }}/pg_ctl reload -D {{ pg_new_datadir }}"
+  when:
+    - socket_access_result.stderr is defined
+    - "'no pg_hba.conf entry' in socket_access_result.stderr"
+
+# pgBackRest (local)
 - block:
     - name: pgbackrest | Check pg-path option
       ansible.builtin.command: "grep -c '^pg.*-path=' {{ pgbackrest_conf_file }}"
@@ -99,7 +113,7 @@
     - pgbackrest_install | bool
     - pgbackrest_repo_host | length < 1
 
-# pgbackrest (dedicated)
+# pgBackRest (dedicated)
 - block:
     - name: pgbackrest | Check pg-path option
       delegate_to: "{{ groups['pgbackrest'][0] }}"
@@ -151,6 +165,36 @@
   ignore_errors: true
   when: wal_g_install | bool
 
+# Wait for the analyze to complete
+- name: "Collecting statistics in progress. Wait for the analyze to complete."
+  ansible.builtin.async_status:
+    jid: "{{ vacuumdb_analyze.ansible_job_id }}"
+  register: vacuumdb_analyze_job_result
+  until: vacuumdb_analyze_job_result.finished
+  retries: "{{ (vacuumdb_analyze_timeout | int) // 10 }}"  # max wait time
+  delay: 10
+  ignore_errors: true  # ignore errors if the task runs for over an vacuumdb_analyze_timeout
+  when:
+    - vacuumdb_analyze is defined
+    - vacuumdb_analyze.ansible_job_id is defined
+
+- name: "Stop pg_terminator script"
+  ansible.builtin.shell: |
+    while read pid; do
+      if ps -p $pid > /dev/null 2>&1; then
+        echo "Stopping pg_terminator with pid: $pid" >> /tmp/pg_terminator.log
+        kill -9 $pid
+      else
+        echo "No process found for pid: $pid" >> /tmp/pg_terminator.log
+      fi
+    done < /tmp/pg_terminator.pid
+  args:
+    executable: /bin/bash
+  ignore_errors: true
+  when: (pg_terminator_analyze is defined and pg_terminator_analyze is changed) or
+        (pg_terminator_long_transactions is defined and pg_terminator_long_transactions is changed)
+
+# finish (info)
 - name: Check the Patroni cluster state
   run_once: true
   become: true
@@ -171,21 +215,6 @@
   changed_when: false
   when: inventory_hostname in groups['primary']
 
-# Return the pg_hba.conf file to its original state (if it has been changed)
-- block:
-    - name: Remove temporary local access rule from pg_hba.conf
-      ansible.builtin.blockinfile:
-        path: "{{ pg_new_confdir }}/pg_hba.conf"
-        marker: "# {mark} ANSIBLE TEMPORARY pg_upgrade RULE"
-        state: absent
-
-    - name: Update the PostgreSQL configuration
-      ansible.builtin.command: "{{ pg_new_bindir }}/pg_ctl reload -D {{ pg_new_datadir }}"
-  when:
-    - socket_access_result.stderr is defined
-    - "'no pg_hba.conf entry' in socket_access_result.stderr"
-
-# finish (info)
 - name: List the Patroni cluster members
   run_once: true
   ansible.builtin.debug:

roles/upgrade/tasks/statistics.yml

@@ -9,7 +9,7 @@
 
 - block:
     # Monitor the locks and terminate the backend blocking the 'ANALYZE' query (for more than 15 seconds)
-    - name: "Start pg_terminator script: Monitor locks and terminate the 'ANALYZE' blockers"
+    - name: "pg_terminator: Monitor locks and terminate the 'ANALYZE' blockers"
       ansible.builtin.shell: |
         echo $$ > /tmp/pg_terminator.pid
         for i in {1..{{ vacuumdb_analyze_timeout // 10 }}}; do
@@ -41,6 +41,36 @@
       ignore_errors: true  # ignore errors if the task runs for over an 'vacuumdb_analyze_timeout'.
       when: pg_new_version is version('9.6', '>=')
 
+    # Monitor long-running transactions and terminate them (for more than 'vacuumdb_analyze_terminate_treshold')
+    - name: "pg_terminator: Monitor and terminate the long-running transactions (more than {{ max_tx_sec }} seconds) during collecting statistics"
+      ansible.builtin.shell: |
+        echo $$ >> /tmp/pg_terminator.pid
+        for i in {1..{{ vacuumdb_analyze_timeout // 10 }}}; do
+          {{ pg_new_bindir }}/psql -p {{ postgresql_port }} -U {{ patroni_superuser_username }} -d postgres -tAXc "
+          select
+            clock_timestamp(),
+            pg_terminate_backend(pid),
+            pid,
+            clock_timestamp() - xact_start as xact_age,
+            left(regexp_replace(query, E'[ \\t\\n\\r]+', ' ', 'g'),150) as query
+          from pg_stat_activity
+          where
+            backend_type = 'client backend' and pid <> pg_backend_pid()
+            and query not ilike 'ANALYZE %'
+            and xact_start < clock_timestamp() - interval '{{ max_tx_sec }}s';" >> /tmp/pg_terminator.log
+          sleep 10
+        done
+      args:
+        executable: /bin/bash
+      async: "{{ vacuumdb_analyze_timeout }}"  # run the command asynchronously with a maximum duration
+      poll: 0
+      register: pg_terminator_long_transactions
+      ignore_errors: true  # ignore errors if the task runs for over an 'vacuumdb_analyze_timeout'.
+      vars:
+        max_tx_sec: "{{ vacuumdb_analyze_terminate_treshold }}"
+      when: pg_new_version is version('10', '>=') and vacuumdb_analyze_terminate_treshold | int > 0
+
+    # ANALYZE
     - name: "Run vacuumdb to analyze the PostgreSQL databases"
       ansible.builtin.command: >
         {{ pg_new_bindir }}/vacuumdb -p {{ postgresql_port }}
@@ -49,24 +79,6 @@
       poll: 0
       register: vacuumdb_analyze
       ignore_errors: true  # ignore errors if the task runs for over an 'vacuumdb_analyze_timeout'.
-
-    - name: "Collecting statistics in progress. Wait for the analyze to complete."
-      ansible.builtin.async_status:
-        jid: "{{ vacuumdb_analyze.ansible_job_id }}"
-      register: vacuumdb_analyze_job_result
-      until: vacuumdb_analyze_job_result.finished
-      retries: "{{ (vacuumdb_analyze_timeout | int) // 10 }}"  # max wait time
-      delay: 10
-      ignore_errors: true  # ignore errors if the task runs for over an vacuumdb_analyze_timeout
-
-    - name: "Stop pg_terminator script"
-      ansible.builtin.shell: |
-        pid=$(cat /tmp/pg_terminator.pid)
-        ps -p $pid > /dev/null 2>&1 && kill -9 $pid
-      args:
-        executable: /bin/bash
-      ignore_errors: true
-      when: pg_terminator_analyze is changed
   when: inventory_hostname in groups['primary']
 
 ...

vars/upgrade.yml

@@ -66,6 +66,8 @@ update_extensions: true  # if 'true', try to update extensions automatically
 
 vacuumdb_parallel_jobs: "{{ [ansible_processor_vcpus | int // 2, 1] | max }}"  # use 50% CPU cores
 vacuumdb_analyze_timeout: 3600  # seconds. The maximum duration of analyze command (soft limit, exceeding won't halt playbook)
+# terminate active queries that are longer than the specified time (in seconds) during the collection of statistics.
+vacuumdb_analyze_terminate_treshold: 0 # (0 = do not terminate active backends)
 
 # Do not perform an upgrade if
 max_replication_lag_bytes: 10485760  # 10 MiB - Maximum allowed replication lag in bytes