1 files changed, 125 insertions, 0 deletions
diff --git a/lib/gitlab/database/transaction/context.rb b/lib/gitlab/database/transaction/context.rb
new file mode 100644
index 00000000000..a50dd30b75b
--- /dev/null
+++ b/lib/gitlab/database/transaction/context.rb
@@ -0,0 +1,125 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Database
+    module Transaction
+      class Context
+        attr_reader :context
+
+        LOG_DEPTH_THRESHOLD = 8
+        LOG_SAVEPOINTS_THRESHOLD = 32
+        LOG_DURATION_S_THRESHOLD = 300
+        LOG_THROTTLE_DURATION = 1
+
+        def initialize
+          @context = {}
+        end
+
+        def set_start_time
+          @context[:start_time] = current_timestamp
+        end
+
+        def increment_savepoints
+          @context[:savepoints] = @context[:savepoints].to_i + 1
+        end
+
+        def increment_rollbacks
+          @context[:rollbacks] = @context[:rollbacks].to_i + 1
+        end
+
+        def increment_releases
+          @context[:releases] = @context[:releases].to_i + 1
+        end
+
+        def set_depth(depth)
+          @context[:depth] = [@context[:depth].to_i, depth].max
+        end
+
+        def track_sql(sql)
+          (@context[:queries] ||= []).push(sql)
+        end
+
+        def duration
+          return unless @context[:start_time].present?
+
+          current_timestamp - @context[:start_time]
+        end
+
+        def depth_threshold_exceeded?
+          @context[:depth].to_i > LOG_DEPTH_THRESHOLD
+        end
+
+        def savepoints_threshold_exceeded?
+          @context[:savepoints].to_i > LOG_SAVEPOINTS_THRESHOLD
+        end
+
+        def duration_threshold_exceeded?
+          duration.to_i > LOG_DURATION_S_THRESHOLD
+        end
+
+        def log_savepoints?
+          depth_threshold_exceeded? || savepoints_threshold_exceeded?
+        end
+
+        def log_duration?
+          duration_threshold_exceeded?
+        end
+
+        def should_log?
+          !logged_already? && (log_savepoints? || log_duration?)
+        end
+
+        def commit
+          log(:commit)
+        end
+
+        def rollback
+          log(:rollback)
+        end
+
+        private
+
+        def queries
+          @context[:queries].to_a.join("\n")
+        end
+
+        def current_timestamp
+          ::Gitlab::Metrics::System.monotonic_time
+        end
+
+        def logged_already?
+          return false if @context[:last_log_timestamp].nil?
+
+          (current_timestamp - @context[:last_log_timestamp].to_i) < LOG_THROTTLE_DURATION
+        end
+
+        def set_last_log_timestamp
+          @context[:last_log_timestamp] = current_timestamp
+        end
+
+        def log(operation)
+          return unless should_log?
+
+          set_last_log_timestamp
+
+          attributes = {
+            class: self.class.name,
+            result: operation,
+            duration_s: duration,
+            depth: @context[:depth].to_i,
+            savepoints_count: @context[:savepoints].to_i,
+            rollbacks_count: @context[:rollbacks].to_i,
+            releases_count: @context[:releases].to_i,
+            sql: queries
+          }
+
+          application_info(attributes)
+        end
+
+        def application_info(attributes)
+          Gitlab::AppJsonLogger.info(attributes)
+        end
+      end
+    end
+  end
+end