update postgresql parameters for db investigations

backend/db-setup/reset-db.sql

@@ -17,3 +17,5 @@ ALTER DEFAULT PRIVILEGES FOR USER simple_report_migrations IN SCHEMA simple_repo
 GRANT USAGE ON LANGUAGE plpgsql to simple_report_app;
 DROP EXTENSION IF EXISTS pgcrypto;
 CREATE EXTENSION IF NOT EXISTS pgcrypto SCHEMA simple_report;
+DROP EXTENSION IF EXISTS pg_stat_statements;
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements SCHEMA simple_report;

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 = -1
+}
+
+# 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 = "off"
+}
+
+# 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 = "none"
+}
+
+# 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 = "off"
+}
+
+# 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 = -1
+}

ops/services/postgres_db/main.tf

@@ -66,3 +66,16 @@ resource "azurerm_postgresql_flexible_server_configuration" "pgms_wait_sampling_
   server_id = azurerm_postgresql_flexible_server.db.id
   value     = "ALL"
 }
+
+resource "azurerm_postgresql_flexible_server_configuration" "postgresql_shared_preload_libraries" {
+  name      = "shared_preload_libraries"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  value     = "AUTO_EXPLAIN,PG_CRON,PG_STAT_STATEMENTS"
+}
+
+# This allows us to install these extensions on the server
+resource "azurerm_postgresql_flexible_server_configuration" "postgresql_extensions" {
+  name      = "azure.extensions"
+  server_id = azurerm_postgresql_flexible_server.db.id
+  value     = "PG_STAT_STATEMENTS,PGCRYPTO,PLPGSQL"
+}