The network messages contain exchange step and task argument workspace data that is communicated between the EXC process and the agent process. ACMS logs one COMPRESSED_MSG event whenever a message is transmitted or received over a network connection, and logs a second COMPRESSED_MSG event when it receives a compressed message over the network. The size of the original message and the size of the compressed message are logged, together with the compression ratio that indicates the factor by which ACMS compressed the data.

15.3.1.2 DECtrace and ACMS Items

Each event has various items associated with it. These items include a set of standard DECtrace resource utilization items and a set of facility-specific items.

Table 15-1 lists the standard resource utilization items.

Table 15-1 Resource Utilization Items

Item	Description	Data type	Usage
BIO	Number of buffered I/O operations	Longword	Counter
DIO	Number of direct I/O operations	Longword	Counter
PAGEFAULTS	Total number of hard and soft page faults	Longword	Counter
PAGEFAULT_IO	Number of hard page faults (that is, page faults to or from the disk)	Longword	Counter
CPU	Total amount of CPU time in tens of milliseconds	Longword	Counter
CURRENT_PRIO	Current priority of the process	Word	Counter
VIRTUAL_SIZE	Number of virtual pages currently mapped for the process	Longword	Counter
WS_SIZE	Current working set size of the process	Longword	Counter
WS_PRIVATE	Number of pages in the working set that are private to the process	Longword	Counter
WS_GLOBAL	Number of pages in the working set that are globally shared among processes on the system	Longword	Counter

The set of standard resource utilization items is often taken as a whole. To facilitate this, the items can be referred to by the group name: RESOURCE_ITEMS.

Table 15-2 describes the items that are specific to ACMS.

Table 15-2 ACMS Data Items

Item	Description	Data type	Usage	When Reported
APPL_SPEC	Application specification	Fixed ASCIC(39)	Text	Start
APPL_NODE	Node name	Fixed ASCIC(15)	Text	Start
TASK_NAME	Task name	Fixed ASCIC(31)	Text	Start
STEP_NAME	Name of exchange or processing step	Fixed ASCIC(31)	Text	Start
REQ_FORM_NAME	Name of the DECforms request	Fixed ASCIC(31)	Text	Start
DEVICE_NAME	Name of user's login device	Fixed ASCIC(8)	Text	Start
PROCEDURE_INDEX	Numeric index uniquely identifying the procedure within the server	Longword	Level	Start
SERVER_NAME	Name of the server executing the procedure	Fixed ASCIC(31)	Text	Start
SEND_ID	DECforms send record ID	Fixed ASCIC(31)	Text	Start
RECEIVE_ID	DECforms receive record ID	Fixed ASCIC(31)	Text	Start
TXN_ID	Transaction ID	Fixed ASCIC(36)	Text	Start
NETWORK_TIME	The NETWORK_TIME item is the part of the response time that is spent in communications over the network between the submitter and application nodes. The NETWORK_TIME item is measured in milliseconds.	Longword	Level	End
PROCESSING_TIME	The PROCESSING_TIME item represents the part of the SUB_RESPONSE response time that is spent in processing on the application node. Together, the NETWORK_TIME and PROCESSING_TIME items make up the entire response time measured by the SUB_RESPONSE event. The PROCESSING_TIME item is measured in milliseconds.	Longword	Level	End
APL_USERNAME	The submitter's OpenVMS user name on the application node. APL_USERNAME is actually the proxy translation of the front-end OpenVMS user name. In previous versions of ACMS, this item was called the SUBMITTER_NAME item.	Fixed ASCIC(12)	Text	Start
SUB_USERNAME	The OpenVMS user name of the submitter, taken from the remote node. Note that the SUB_USERNAME item is not the same as the SUBMITTER_NAME item available in previous versions of ACMS.	Fixed ASCIC(12)	Text	Start
EXCH_STEP_NAME	The label of the most recently executed exchange step. For those events reported at the beginning of a task, before any exchange step has executed, this item holds the string ACMS$TASK_BEGIN.	Fixed ASCIC(31)	Text	Start
PARENT_TASK	An item used when a task is called by another task. The PARENT_TASK item holds the name of the calling task. ACMS leaves this item blank, if the TASK event is not a called task.	Fixed ASCIC(31)	Text	Start
PROC_STEP_TYPE	An item that identifies the function of a processing step. The PROC_STEP_TYPE item holds one of the following strings: ACMS$PROCEDURE_CALL ACMS$DCL_SERVER ACMS$TASK_CALL In previous versions of ACMS, PROCESSING_STEP events were logged only on steps that made procedure calls or DCL server commands.	Fixed ASCIC(20)	Text	Start
PROCEDURE_NAME	The name of the step procedure in the procedure server. The PROCEDURE_NAME item makes the final performance report easier to interpret, in comparison to the PROCEDURE_INDEX item. TDB files built with versions of ACMS previous to Version 3.3 do not contain procedure names. In this case, ACMS logs the following string to DECtrace for the PROCEDURE_NAME item: ACMS$PROCEDURE_<procedure_index>	Fixed ASCIC(31)	Text	Start
SERVER_INDEX	The numeric index of the server in the application.	Longword	Level	Start
TXN_STATUS	An identifier field that describes the final status of a DECdtm transaction. The field format is ACMS$<vms-identifier>, where <vms-identifier> is the identifier field of a standard OpenVMS message, for example ACMS$NORMAL.	Fixed ASCIC(31)	Text	End
ORIGINAL_SIZE	A longword value that represents the size, in bytes, of a network message prior to data compression.	Longword	Level	Point
COMPRESSED_SIZE	A longword value that represents the size, in bytes, of a network message that has been compressed.	Longword	Level	Point
COMPRESSN_RATIO	A longword value that represents the percentage of data compression achieved. The compression ratio is expressed as a percentage in the range 0 to 99. A value of 0 indicates that ACMS was not able to compress the message. A value in the range 1 to 99 indicates the amount by which ACMS was able to reduce the size of the message. ACMS uses the following formula to calculate the compression ratio: RATIO = (( ORIG_SIZE ­ COMP_SIZE ) / ORIG_SIZE) * 100 In the formula, ORIG_SIZE is the size of the original message and COMP_SIZE is the size of the compressed message.	Longword	Level	Point
MESSAGE_SRC	The name of the node that sends the network message.	Fixed ASCIC(15)	Text	Point
MESSAGE_DEST	The name of the node that receives the network message.	Fixed ASCIC(15)	Text	Point

15.3.1.3 DECtrace Cross Facility Items

The DECtrace cross facility items allow users who interpret DECtrace data to better understand the context in which certain events are executed and reported in DECtrace. The cross facility items are DECtrace items whose values can be set by one facility and then collected by any number of facilities. Use of cross facility items enables facilities that operate together to relate events in the final DECtrace report. To relate events across facilities, the events in both facilities must collect the value of the cross facility item in common.

Table 15-3 lists the DECtrace cross facility items.

Table 15-3 Cross Facility Items

Item	Description	Data type	Usage
CROSS_FAC_2	Represents the ACMS SERVER_INDEX data item	Longword	Level
CROSS_FAC_7	Represents the ACMS PROCEDURE_INDEX data item	Longword	Level
CROSS_FAC_14	For general, unrestricted use.	Longword	Level

In ACMS, the PROCEDURE_CALL event collects the SERVER_INDEX (CROSS_FAC_2) and PROCEDURE_INDEX (CROSS_FAC_7) items. The PROCEDURE_CALL event is defined in the ALL, PERFORMANCE, and RESPONSE classes.

Rdb collects the CROSS_FAC_2 and CROSS_FAC_7 items during the TRANSACTION event, which is included in the Rdb PERFORMANCE, ALL and RDBEXPERT classes.

Additionally, DECtrace provides a cross facility item, CROSS_FAC_14, for general, unrestricted use. You can define this cross facility item for your application needs. ACMS includes collection of the CROSS_FAC_14 item in all events.

15.3.2 How to Use Cross Facility Items

The following description and example shows how DECtrace uses cross facility items to relate the ACMS PROCEDURE_CALL event to Rdb TRANSACTION events.

Just prior to ACMS executing the start of the PROCEDURE_CALL event within the application, ACMS reports a unique identifier to DECtrace. The unique identifier is implemented using two longwords: the ACMS server and procedure indexes. DECtrace stores the longword value for the server index in the CROSS_FAC_2 item, and the value for the procedure index in the CROSS_FAC_7 item.

ACMS logs the start of the PROCEDURE_CALL event, and begins to collect the cross facility item values reported to DECtrace just prior to the start event. The same cross facility items are included in the start event collections for subsequent ACMS PROCEDURE_CALL and Rdb TRANSACTION events, until ACMS reports new values to DECtrace.

Figure 15-3 illustrates two PROCEDURE_CALL events, each of which includes Rdb TRANSACTION events. The server index for both procedure calls is 5; the procedure indexes are 27 and 14, respectively.

Figure 15-3 Relating the ACMS PROCEDURE_CALL and Rdb TRANSACTION Events

In Figure 15-3, the following actions occur:

1. Just before ACMS executes the first procedure, the two index values, 5 and 27, are sent to DECtrace to be stored in two cross facility items. After this, start events for the first PROCEDURE_CALL and two TRANSACTION events collect these item values from DECtrace.
2. Before the second procedure begins, the indexes 5 and 14 are written to the same cross facility items, replacing their previous values. The PROCEDURE_CALL and TRANSACTION start events that follow include the cross facility item values in their data collection. This continues for all such event occurrences and, in the end, all related PROCEDURE_CALL and TRANSACTION events have these cross facility items in common.

In the final report, DECtrace relates events based on common cross facility item values. As a result, the Rdb TRANSACTION events are grouped with the appropriate ACMS PROCEDURE_CALL events in the report listing. In this way, you can distinguish which transactions are performed within Procedure 27, and which procedures initiated occurrences of Transaction A.

15.4 ACMS Collection Classes

Collection classes are made up of a predefined set of events and associated items. You can collect a set of related events, based on the class in which they are defined.

Table 15-4 summarizes the events and items collected in the ACMS collection classes.

Table 15-4 ACMS Collection Classes

Class Name	Events Collected	Items Collected1
ALL	All events	*
ALL_NO_CF	All events	Cross facility items are not collected
PERFORMANCE	All events, except: SUB_RESPONSE APL_RESPONSE	*
PERFORMANCE_NO_CF	All events, except: SUB_RESPONSE APL_RESPONSE	Cross facility items are not collected
RESPONSE	SUB_RESPONSE APL_RESPONSE TRANSACTION PROCESSING_STEP TASK_WAIT PROCEDURE_CALL	*
RESPONSE_NO_CF	SUB_RESPONSE APL_RESPONSE TRANSACTION PROCESSING_STEP TASK_WAIT PROCEDURE_CALL	Cross facility items are not collected

Table 15-5 lists the events and items that make up the ALL collection class. The ALL class is composed of the full set of events and items available for collection from a product. Note that the ALL_NO_CF class is the default class for ACMS.

Table 15-5 Events and Items Available in the ALL Collection Class for ACMS

Event	Event Type	Items
TASK	Duration	APPL_SPEC, TASK_NAME, PARENT_TASK, STEP_NAME, SUB_USERNAME, APL_USERNAME, CROSS_FAC_14
EXCHANGE_STEP	Duration	APPL_SPEC, DEVICE_NAME, REQ_FORM_NAME, STEP_NAME, TASK_NAME, SEND_ID, RECEIVE_ID, SUB_USERNAME, APL_USERNAME, CROSS_FAC_14
PROCESSING_STEP	Duration	APPL_SPEC, STEP_NAME, TASK_NAME, TXN_ID, SUB_USERNAME, APL_USERNAME, PROC_STEP_TYPE, EXCH_STEP_NAME, CROSS_FAC_14
PROCEDURE_CALL	Duration	APPL_SPEC, PROCEDURE_INDEX, SERVER_NAME, STEP_NAME, TASK_NAME, RESOURCE_ITEMS, TXN_ID, SUB_USERNAME, APL_USERNAME, PROCEDURE_NAME, SERVER_INDEX, EXCH_STEP_NAME, CROSS_FAC_2, CROSS_FAC_7, CROSS_FAC_14
REMOTE_REQUEST	Duration	APPL_NODE, APPL_SPEC, DEVICE_NAME, REQ_FORM_NAME, TASK_NAME, SUB_USERNAME, EXCH_STEP_NAME, CROSS_FAC_14
FORMS_ENABLE	Duration	APPL_NODE, APPL_SPEC, DEVICE_NAME, REQ_FORM_NAME, SUB_USERNAME, CROSS_FAC_14
FORMS_REQUEST	Duration	APPL_NODE, APPL_SPEC, DEVICE_NAME, SEND_ID, RECEIVE_ID, SUB_USERNAME, TASK_NAME, REQ_FORM_NAME, EXCH_STEP_NAME, CROSS_FAC_14
TASK_WAIT	Duration	APPL_SPEC, TASK_NAME, SERVER_NAME, TXN_ID, STEP_NAME, PROCEDURE_NAME, SUB_USERNAME, APL_USERNAME, EXCH_STEP_NAME, CROSS_FAC_14
TRANSACTION	Duration	APPL_SPEC, TASK_NAME, STEP_NAME, TXN_ID, SUB_USERNAME, APL_USERNAME, TXN_STATUS, EXCH_STEP_NAME, CROSS_FAC_14
SUB_RESPONSE	Duration	APPL_NODE, APPL_SPEC, DEVICE_NAME, TASK_NAME, EXCH_STEP_NAME, NETWORK_TIME, PROCESSING_TIME, SUB_USERNAME, CROSS_FAC_14
APL_RESPONSE	Duration	APPL_SPEC, TASK_NAME, APL_USERNAME, EXCH_STEP_NAME, SUB_USERNAME, CROSS_FAC_14
COMPRESSED_MSG	Point	ORIGINAL_SIZE, COMPRESSED_SIZE, COMPRESSN_RATIO, MESSAGE_SRC, MESSAGE_DEST, CROSS_FAC_14

Table 15-6 lists the events and items that make up the PERFORMANCE collection class. The PERFORMANCE collection class includes events and items that are useful for applications and database tuning. DECtrace collects all items associated with events in this class.

Table 15-6 Events and Items Available in the PERFORMANCE Class for ACMS

Event	Event Type	Items1
TASK	Duration	*
EXCHANGE_STEP	Duration	*
PROCESSING_STEP	Duration	*
PROCEDURE_CALL	Duration	*
REMOTE_REQUEST	Duration	*
FORMS_ENABLE	Duration	*
FORMS_REQUEST	Duration	*
TASK_WAIT	Duration	*
TRANSACTION	Duration	*
COMPRESSED_MSG	Point	*

Table 15-7 lists the events and items that make up the RESPONSE collection class. The RESPONSE class groups together events and items that are commonly used in ACMS response time measurements. For each event, DECtrace collects all items associated with the event.

Table 15-7 Events and Items Available in the RESPONSE Collection Class for ACMS

Event	Event Type	Items1
SUB_RESPONSE	Duration	*
APL_RESPONSE	Duration	*
TRANSACTION	Duration	*
PROCESSING_STEP	Duration	*
TASK_WAIT	Duration	*
PROCEDURE_CALL	Duration	*