Read/Write Lock Diagnostics

The Read/Write Lock Diagnostics category provides summary information about database lock usage. You can use this information when analyzing system performance.

The database locks are shown in rows, with each row representing a different lock. The status information shown for each lock is as follows:

• Lock Name—The Lock Name is the name of the lock in ClearSCADA and indicates what or who has requested the lock.
• Lock Type—The Lock Type is either DB for the main database lock which protects all data, or Metadata which protects changes to the Metadata in ClearSCADA (via the Edit Metadata option that is available from the context sensitive menu on the root group (see Display the Metadata Window)).
• Start Time—The Start Time is the time that the lock was first acquired. This is either from when ClearSCADA was started, after a snapshot interval if the ResetCountersOnSnapshot log file setting is true, or after a manual reset in the Server Status tool.
• Last Access—Last Access is the last time that the lock was acquired.
• Write Locks— Write Locks is the total number of write locks, either from startup or since the lock diagnostics were last reset.
• Write Locks Per Second— Write Locks Per Second is the number of write locks per second as an average of the same period.

• Average Write Lock—The Average Write Lock is the average time spent in a write lock for the lock.

• Longest Write Lock—Longest Write Lock is the duration of longest write lock, either since start-up or since the lock diagnostics were last reset.
• Longest Write Lock Time— Longest Write Lock Time is the time stamp of longest write lock.
• Time in Write Lock—Time in Write Lock is the total time spent in write lock either since start-up or since the lock diagnostics were last reset. It is expressed as a percentage.
• Average Write Lock Wait—The Average Write Lock Wait is the average time to wait to acquire a write lock.
• Longest Write Lock Wait—Longest Write Lock Wait is the longest time to wait to acquire a write lock.
• Longest Write Lock Wait Time—The Longest Write Lock Wait Time is the time stamp of the longest time to wait to acquire a write lock.
• Read Locks—Read Locks is the total number of read locks, either from startup or since the lock diagnostics were last reset.
• Read Locks Per Second—Read Locks Per Second is the number of read locks per second as an average of the same period.
• Average Read Lock—The Average Read Lock is the average time the lock spent in a read lock.
• Longest Read Lock—The Longest Read Lock is the duration of longest read lock, either since start-up or since the lock diagnostics were last reset.
• Longest Read Lock Time—The Longest Read Lock Time is the time stamp of the longest read lock time.
• Time in Read Lock—The Time in Read Lock is the total time in read lock, either since start-up or since the lock diagnostics were last reset. It is expressed as a percentage.
• Average Read Lock Wait—The Average Read Lock Wait is the average time to wait to acquire a write lock.
• Longest Read Lock Wait—The Longest Read Lock Wait is the longest time to wait to acquire a read lock.
• Longest Read Lock Wait Time—The Longest Read Lock Wait Time is the time stamp of longest time to wait to acquire a read lock.

For Read/Write Locks, you can access a context sensitive menu by right-clicking on an entry in the list.

The options that are available are:

• Reset Lock Diagnostic—Select this option to reset the selected lock diagnostic.
• Reset All Lock Diagnostics—Select this option to reset all of the lock diagnostics.
• Enable Diagnostics—Select this option to enable Lock Diagnostics. The option is only available for use when the Lock Diagnostics are disabled. Locks per type are acquired.
• Disable Diagnostics—Select this option to disable all Lock Diagnostics. The comment 'Per-lock diagnostics disabled' replaces the list of locks.