x_lock_escals - Exclusive lock escalations monitor element
The number of times that locks have been escalated from several row locks to one exclusive table lock, or the number of times an exclusive lock on a row caused the table lock to become an exclusive lock.
Snapshot Level | Logical Data Grouping | Monitor Switch |
---|---|---|
Database | dbase | Basic |
Application | appl | Basic |
Event Type | Logical Data Grouping | Monitor Switch |
---|---|---|
Database | event_db | Always collected |
Connection | event_conn | Always collected |
Transactions | event_xact | Always collected |
Usage
Other applications cannot access data held by an exclusive lock; therefore it is important to track exclusive locks since they can impact the concurrency of your data.
A lock is escalated when the total number of locks held by an application reaches the maximum amount of lock list space available to the application. The amount of lock list space available is determined by the locklist and maxlocks configuration parameters.
When an application reaches the maximum number of locks allowed and there are no more locks to escalate, it will then use space in the lock list allocated for other applications. When the entire lock list is full, an error occurs.
See the lock_escals monitor element for possible causes and resolutions to excessive exclusive lock escalations.
An application may be using exclusive locks when share locks are sufficient. Although share locks may not reduce the total number of lock escalations share lock escalations may be preferable to exclusive lock escalations.
xda_object_pages - XDA Object Pages monitor element
The number of disk pages consumed by XML storage object (XDA) data.
- Element identifier
- xda_object_pages
- Element type
- information
Snapshot Level | Logical Data Grouping | Monitor Switch |
---|---|---|
Table | table | Basic |
Event Type | Logical Data Grouping | Monitor Switch |
---|---|---|
Tables | event_table | Always collected |
- Usage
- This element provides a mechanism for viewing the actual amount of space consumed by XML storage object (XDA) data in a particular table. This element can be used in conjunction with a table event monitor to track the rate of XML storage object data growth over time.
xda_object_l_pages - XML storage object (XDA) data logical pages monitor element
The number of logical pages used on disk by XML storage object (XDA) data.
Table Function | Monitor Element Collection Level |
---|---|
MON_GET_TABLE table function - Get table metrics | Always collected |
Usage
- This value might
be less than the amount of space physically allocated for the object.
This can happen when you use the REUSE STORAGE option of the TRUNCATE
statement. This option causes storage allocated for the table to continue
to be allocated, although the storage will be considered empty. In
addition, the value for this monitor element might be less than the
amount of space logically allocated for the object, because the total
space logically allocated includes a small amount of additional meta
data.
To retrieve an accurate measure of the logical or physical size of an object, use the ADMIN_GET_TAB_INFO_V97 function. This function provides more accurate information about the size of objects than you can obtain by multiplying the number of pages reported for this monitor element by the page size.
xid - Transaction ID monitor element
A unique transaction identifier (across all databases) generated by a transaction manager in a two-phase commit transaction.
Snapshot Level | Logical Data Grouping | Monitor Switch |
---|---|---|
DCS Application | dcs_appl | Unit of Work |
- Usage
- This identifier can be used to correlate the transaction generated by the transaction manager with the transactions executed against multiple databases. It can be used to help diagnose transaction manager problems by tying database transactions involving a two-phase commit protocol with the transactions originated by the transaction manager.
xmlid - XML ID monitor element
A unique document ID. The ID is derived as follows: <event_header>_<event_id>_<event_type>_<event_timestamp>_<partition>.
Table Function | Monitor Element Collection Level |
---|---|
EVMON_FORMAT_UE_TO_TABLES procedure - move an XML document to relational tables | Not applicable; reports whichever elements are in the XML document that is provided as input to the formatting function. |
EVMON_FORMAT_UE_TO_XML table function - convert unformatted events to XML | Not applicable; reports whichever elements are in the XML document that is provided as input to the formatting function. |
Event Type | Logical Data Grouping | Monitor Switch |
---|---|---|
Locking | ||
Package Cache |
xquery_stmts - XQuery Statements Attempted monitor element
The number of XQuery statements executed for an application or database.
Snapshot Level | Logical Data Grouping | Monitor Switch |
---|---|---|
Database | dbase | Basic |
Application | appl | Basic |
Event Type | Logical Data Grouping | Monitor Switch |
---|---|---|
Connection | event_conn | Always collected |
Database | event_db | Always collected |
Statistics | event_scmetrics | REQUEST METRICS BASE |
Statistics | event_wlmmetrics | REQUEST METRICS BASE |
Unit of work | uow_metrics | REQUEST METRICS BASE |
- Usage
- You can use this element to gauge the activity of native XQuery language requests. This does not include embedded XQuery language requests such as xmlquery, xmltable, or xmlexist.