update postgresql parameters for db investigations

backend/src/main/resources/db/changelog/db.changelog-master.yaml

@@ -4723,4 +4723,15 @@ databaseChangeLog:
             tag: drop-test_order_id-not_null_constraint-from-result
         - dropNotNullConstraint:
             tableName: result
-            columnName: test_order_id
+            columnName: test_order_id
+  - changeSet:
+      id: create-pg-stat-statements-extension
+      author: [email protected]
+      comment: Install the pg_stat_statements extension.
+      changes:
+        - sql:
+            sql: CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+      rollback:
+        - sql:
+            sql: -- DROP EXTENSION IF EXISTS pg_stat_statements;
+            comment: Dropping the extension requires superuser permissions, and we don't want to give that to the migration user, so we have to do nothing here.

ops/services/postgres_db/investigation.tf

@@ -0,0 +1,46 @@
+# These are disabled by default to avoid performance impact.
+
+# https://www.postgresql.org/docs/current/runtime-config-logging.html
+resource "azurerm_postgresql_flexible_server_configuration" "log_min_duration_statement" {
+  name      = "log_min_duration_statement"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  # To enable: this is in milliseconds, update this to a positive value in milliseconds to enable this logging
+  # To disable: update this to -1
+  value     = 30
+}
+
+# https://www.postgresql.org/docs/current/runtime-config-statistics.html
+resource "azurerm_postgresql_flexible_server_configuration" "track_io_timing" {
+  name      = "track_io_timing"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  # To enable: update this to "on" to enable
+  # To disable: update this to "off"
+  value     = "on"
+}
+
+# https://www.postgresql.org/docs/current/pgstatstatements.html
+resource "azurerm_postgresql_flexible_server_configuration" "pg_stat_statements_track" {
+  name      = "pg_stat_statements.track"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  # To enable: update this to "top" or "all" to enable'
+  # To disable: update this to "none"
+  value     = "all"
+}
+
+# https://www.postgresql.org/docs/current/auto-explain.html
+resource "azurerm_postgresql_flexible_server_configuration" "auto_explain_log_analyze" {
+  name      = "auto_explain.log_analyze"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  # To enable: update this to "on" to enable
+  # To disable: update this to "off"
+  value     = "on"
+}
+
+# https://www.postgresql.org/docs/current/auto-explain.html
+resource "azurerm_postgresql_flexible_server_configuration" "auto_explain_log_min_duration" {
+  name      = "auto_explain.log_min_duration"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  # To enable: this is in milliseconds, update this to a positive value in milliseconds to enable this logging
+  # To disable: update this to -1
+  value     = 30
+}

ops/services/postgres_db/main.tf

@@ -66,3 +66,10 @@ resource "azurerm_postgresql_flexible_server_configuration" "pgms_wait_sampling_
   server_id = azurerm_postgresql_flexible_server.db.id
   value     = "ALL"
 }
+
+# This allows us to install these extensions on the server
+resource "azurerm_postgresql_flexible_server_configuration" "azure_extensions" {
+  name      = "azure.extensions"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  value     = "PG_STAT_STATEMENTS,PGCRYPTO,PLPGSQL"
+}