OSEE/ReqAndDesign

Logging

Requirements

• shall handle thousands of log entries per second
• log entries shall be quickly accessible based on any combination of server, user, timestamp, log type, duration, status
• log entries shall be accessible (especially) when an application server is unresponsive
• log entries shall be available until they are deleted by an admin or admin policy (applied by server automatically)
• at run-time logging shall be enabled/disabled based on any combination of user, source, and type

Design

id, parent_id, timestamp, user, type_id, duration, status, details (maybe in JSON format)

• id - random long returned for log method call
• parent_id - id negative for root entries and is the id of source of the entry (IDE client, server, etc.)
• timestamp - long with ms since epoch
• user - long user id (artifact id of a user artifact)
• type_id - a fine-grained application defined type (might use ranges) defined as tokens with a long and name (which is not in db)
• log entries where duration does not apply have a duration of -1
• log entries where duration applies start with a duration of -2 and are updated only when the associated job ends
• Status:

 0-99    percent complete
 200 OK  completed normally
 4xx     client error (as defined for HTTP Status Code Definitions)
 500     server error (as defined for HTTP Status Code Definitions)

• server uses a queue to collect log entries for a short time (configurable) and then insert them in batch. This means that any update to a log entry that occurs in less than this configured time will not require a database update (i.e. writing the duration of a short operation).

 Optimize JDBC Performance

Exception Handeling

Requirements

• avoid unnecessary wrapping of exceptions

Design

Checked exceptions I love you, but you have to go Why should you use Unchecked exceptions over Checked exceptions Clean Code by Example: Checked versus unchecked exceptions

• Use application specific exceptions that extend RuntimeException - application specific allows for setting exception breakpoints in the debugger
• Do not declare any run-time exceptions in any method signatures