Log SQL counts from save pipeline step

config/feature_flags/development/ci_pipeline_logger_sql.yml

+---
+name: ci_pipeline_logger_sql
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/77117
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/346246
+milestone: '14.7'
+type: development
+group: group::pipeline execution
+default_enabled: false

lib/gitlab/ci/pipeline/chain/create.rb

@@ -9,7 +9,7 @@ module Gitlab
           include Gitlab::Utils::StrongMemoize
 
           def perform!
-            logger.instrument(:pipeline_save) do
+            logger.instrument(:pipeline_save, sql: true) do
               BulkInsertableAssociations.with_bulk_insert do
                 tags = extract_tag_list_by_status
 

lib/gitlab/ci/pipeline/logger.rb

@@ -23,16 +23,18 @@ module Gitlab
           log_conditions.push(block)
         end
 
-        def instrument(operation)
+        def instrument(operation, sql: false)
           return yield unless enabled?
 
           raise ArgumentError, 'block not given' unless block_given?
 
+          op_start_db_counters = current_db_counter_payload if sql && sql_logging_enabled?
           op_started_at = current_monotonic_time
 
           result = yield
 
           observe("#{operation}_duration_s", current_monotonic_time - op_started_at)
+          observe_sql(operation, op_start_db_counters) if sql && sql_logging_enabled?
 
           result
         end
@@ -97,6 +99,25 @@ module Gitlab
         def observations
           @observations ||= Hash.new { |hash, key| hash[key] = [] }
         end
+
+        def observe_sql(operation, start_db_counters)
+          current_db_counter_payload.each do |key, value|
+            result = value - start_db_counters.fetch(key, 0)
+            next if result == 0
+
+            observe("#{operation}_#{key}", result)
+          end
+        end
+
+        def current_db_counter_payload
+          ::Gitlab::Metrics::Subscribers::ActiveRecord.db_counter_payload
+        end
+
+        def sql_logging_enabled?
+          strong_memoize(:sql_logging_enabled) do
+            ::Feature.enabled?(:ci_pipeline_logger_sql, project, default_enabled: :yaml)
+          end
+        end
       end
     end
   end

spec/lib/gitlab/ci/pipeline/logger_spec.rb

@@ -39,6 +39,38 @@ RSpec.describe ::Gitlab::Ci::Pipeline::Logger do
       expect { logger.instrument(:expensive_operation) }
         .to raise_error(ArgumentError, 'block not given')
     end
+
+    context 'with SQL instrumentation', :request_store do
+      it "returns the block's value" do
+        expect(logger.instrument(:expensive_operation, sql: true) { Project.count }).to eq(Project.count)
+      end
+
+      it 'includes SQL metrics' do
+        loggable_data = %w[
+          expensive_operation_duration_s
+          expensive_operation_db_count
+          expensive_operation_db_primary_count
+          expensive_operation_db_primary_duration_s
+          expensive_operation_db_main_count
+          expensive_operation_db_main_duration_s
+        ].each.with_object({}) do |key, accumulator|
+          accumulator[key] = {
+            'count' => 1,
+            'avg' => a_kind_of(Numeric),
+            'max' => a_kind_of(Numeric),
+            'min' => a_kind_of(Numeric)
+          }
+        end
+
+        logger.instrument(:expensive_operation, sql: true) { Project.count }
+        expect(logger.observations_hash).to match(a_hash_including(loggable_data))
+      end
+
+      it 'does not include SQL metrics when there is no SQL operation' do
+        logger.instrument(:expensive_operation, sql: true) { 123 }
+        expect(logger.observations_hash.keys).to match_array(['expensive_operation_duration_s'])
+      end
+    end
   end
 
   describe '#observe' do