Chapter 5: Monitor Utility

This chapter describes the Monitor utility.

Access and Control

Once the XDB Server is running, you can monitor XDB Server activity in any of the following ways:

Direct Access. You can run the Monitor Utility (xdbmonn.exe) on the server machine.
Remote Access. You can run the Monitor Utility (xdbmonn.exe) from a client machine.
Virtual Statistics Queries. You can use SQL to query the Virtual Statistics Tables. See the chapter Performance Tuning for more information on Virtual Statistics Tables.

Function Summary

The Monitor utility provides access to the information described in the following table. The remainder of this chapter presents detailed information about each function.

Function	Description
User Activity	Displays information about each currently logged on user. Information includes isolation level and time logged on. An asterisk preceding an AuthID indicates that the user has a query open.
Server Status	Provides information on the number of users logged in, the number of queries open, and other useful information.
User Resource Statistics	Displays each user's system resource usage, including the number of queries, table locks (exclusive and shared), and record locks (exclusive and shared).
Memory Manager Statistics	Displays information about the amount of memory currently in use.
Cache Statistics	Displays caching and input/output statistics for the XDB Server cache manager. Monitor cache statistics when your system is running at steady state will help you determine the most effective amount of cache to allocate.
Halt Query	Stops a potentially long sort or query that is in progress.
Delete User	Aborts a user session when a user's workstation fails. The interrupted transaction is rolled back automatically.
Shutdown Server	Shuts down the XDB Server.

User Activity displays information about the users currently logged in to the XDB Server. If the lines of data exceed the screen size, the information will scroll automatically, pausing at each section.

Note: When a user performs certain functions (such as viewing a list of locations) in text mode tools, the system creates a new internal user in order to access the system location. The monitor will display this user in the User Activity information (with a system-generated name) along with the other "real" users.

User Name

Generally, this is the AuthID used to log on to the XDB Server. If the value in this field is prefixed with an asterisk (*), the user has a query open.

When security is on, the USER NAME displayed is the AuthID under which the user logged into the XDB Server. If security is off, the USER NAME displayed is the same as the Primary AuthID for the client, as set through Options Utility.

If the user has a Secondary ID, the Secondary ID will be shown. If the user has been reassigned a different AuthID via server-to-server inbound or outbound mapping, the re-assigned (new) AuthID is shown.

Some user operations that access the SYSTEM location (such as displaying a list of tables or other browse features) temporarily create a pseudo user, PUBLIC1.

Node ID

This field displays the name of the node from which the user is working. The node name is set through Options Utility for SQLWizard clients on the client workstation. Each client machine must have a unique node name. If there are several clients (AuthIDs or sessions) with the same node name, the node name is appended with a number to indicate the session ID of the client session.

While the same AuthID and node name can be used to log in multiple times (from several different Wintel sessions, for example), the combination of AuthID, node name and session ID together are always unique.

Current Location

This field displays the name of the currently open location.

ILevel

This field displays the isolation level at which the user is currently working. The isolation level is set in any of the following ways:

Through the Options Utility
By using the SET ISOLATION command
By using the new WITH clause on certain SQL statements (DB2 4.x)

See the SQL Reference for information about the SET ISOLATION command and the WITH clause.

Autocommit

This field displays the user's current autocommit level. Set the autocommit level with the Options Utility, or use the SET AUTOCOMMIT command. See the SQL Reference for information about the SET AUTOCOMMIT command.

Logged in Since

This field displays the date and time the user logged in to the XDB Server.

Server Status

Server Status information includes the type and number of requests the XDB Server is currently processing and the XDB Server configuration settings.

Note: When running remotely, the Monitor Utility cannot read the server configuration, and therefore cannot display all of the information in Server Status. The term "N/A" replaces unavailable information.

Server Status displays two types of information:

Dynamic information for the current and set maximum of a number of XDB Server parameters.
Static information that is constant while the XDB Server is running.

Dynamic Server Information

Dynamic server information displays current server activity (CURRENT column), and the limit set in the server configuration (MAXIMUM column) for the following values:

Values	Description
Users	Number of users logged into the XDB Server.
Active Users	Number of users with open SELECT queries.
Open Locations	Number of locations with open SELECT queries.
Open Files	Number of logically open files.
Open Queries	Number of open SELECT queries.
Lock Blocks In Use	Number of lock blocks in use.

Use the XDB Server Configuration Utility to set the limits for open locations, open files, open queries, and lock table size.

Static Server Information

Static server information is constant while the XDB Server is running, and includes:

Values	Description
Server Running Since	Date and time the XDB Server was started.
System Location Path	Path where the SYSTEM location for the XDB Server resides.
Temporary Path	Path where temporary files for the XDB Server are stored.
System Usage Monitor	Status of the system usage monitor (on or off).
System Security	Status of system security (on or off).
Packet Ver	Current XDB Server packet version.

Set the system location path, temporary path, system usage monitor, and system security parameters using the XDB Server Configuration utility.

User Resource Statistics

User Resource Statistics information includes query and lock statistics for each AuthID/Node currently using the XDB Server. If the user information exceeds the screen size, use PgUp, PgDn, up-arrow, and down-arrow to scroll through the information.

User

Generally, this is the AuthID used to log on to the XDB Server. When security is on, the USER NAME displayed is the AuthID with which the user logged into the XDB Server. If security is off, the USER NAME displayed is the same as the Primary AuthID for the client, as set through the Options Utility.

Some user operations that access the SYSTEM location (such as displaying a list of tables or other browse features) temporarily create a pseudo user, PUBLIC1.

Information	Description
Node	This field displays the node name from which the user is working. The node name is set through the Options Utility on the client workstation. Each client machine must have a unique node name. If there are several users (AuthIDs or sessions) with the same node name, the node name is appended with a number to indicate the session ID of the client session. While the same AuthID and node name can be used to log in multiple times (from several different Windows NT sessions, for example), the combination of AuthID, node name and session ID together are always unique.
QDs	This field displays the number of open queries.
TsLocks	This field displays the number of shared table locks.
TxLocks	This field displays the number of exclusive table locks.
RsLocks	This field displays the number of shared record locks.
RxLocks	This field displays the number of exclusive record locks.

Memory Manager Statistics

The Memory Manager Statistics Screen displays information about the amount of memory currently in use as follows:

Information	Description
Total Memory From OS	Total Memory From OS displays the total number of bytes (cumulative) allocated from the operating system.
Number Allocations From OS	Number Allocations From OS is the total number of memory allocations from the operating system (cumulative).
Current Allocations From OS	Current Allocations From OS is the current number of outstanding memory allocations from the operating system.

Cache Statistics

The Cache Statistics screen displays caching statistics based on the cache option configured via the XDB Server Configuration utility. The screen displays information in units of 4K memory pages. You can use this information to analyze cache hit ratios and monitor cache effectiveness. The statistics include caching information for all table, dictionary, and index files.

Information	Description
Total Pages	Shows the number of pages in the cache.
Page Size	Size of each page in bytes.
Pages in Use	Percentage of the cache pages allocated to all files that use this cache.
Dirty	Percentage of total pages in the cache that have not yet been written to disk.
Cache Reads	Total number of pages requested from the cache.
Pages Read	Total number of pages read into the cache from disk.
Disk Reads	Total number of read I/O calls performed. Matches pages read, since pages are requested only one at a time.
Read Hit	Percentage of pages requested that did not require a disk read I/O operation.
Cache Writes	Total number of dirty pages released to the cache.
Pages Written	Total number of pages written to disk.
Disk Writes	Total number of disk write I/O calls performed. This number may be less than pages written since flushing causes a series of pages to be written to an accumulator first, and then all written together in one I/O.
Write Hit	Percentage of pages released dirty to the cache that were not written to the disk.
Tosses	Number of cache pages allocated to a file that were written out to disk to make room for a new page.
Checkpoints	Number of checkpoint calls made to this cache.

Halt Query

Use the Halt Query option to stop the processing of any DML command (DELETE, INSERT, SELECT, and UPDATE). Halt Query is especially useful when a user's workstation hangs or when a potentially long query needs to be aborted.

If security is on, you must have SYSADM authority on the SYSTEM location (or have super user privileges) to perform this operation.

To halt a query:

Press F8. A window containing AuthIDs (user names) and nodes appears.
Use the up-arrow and down-arrow keys to highlight the name of the user whose query you want to halt.
Press Enter. Confirm the action when requested.

Delete User

Use the Delete User option to deactivate (cancel) a particular user session. If security is on, you must have SYSADM authority on the SYSTEM location (or have super user privileges) to perform this operation.

To delete a user:

Press F9. A window containing AuthIDs (user names) and nodes appears.
Use the up-arrow and down-arrow keys to highlight the name of the user whose query you want to halt.
Press Enter. Confirm the action when requested.

If the logging system is on, the XDB Server will roll back and delete the session for the user selected.

Shutdown Server

You can press the F10 key to shut down the server. If users are active, the monitor asks you to confirm the action.

If users are active when you shut down an XDB Server, their sessions will be terminated in mid-transaction, as though the XDB Server crashed. When the XDB Server is restarted, all incomplete transactions will be rolled back the next time that location is accessed. Use care, since user programs running on the workstations may not handle a case where the XDB Server no longer responds.
If a query is active when you shut down an XDB Server, the XDB Server will wait until the function is completed before shutting down.