126 DBMS_SERVER_ALERT

The DBMS_SERVER_ALERT package enables you to configure the Oracle Database server to issue an alert when a threshold for a specified server metric has been violated. You can configure both warning and critical thresholds for a large number of predefined metrics.

If a warning threshold is reached, the server generates a severity level 5 alert. If a critical threshold is reached, the server generates a severity level 1 alert.

The chapter contains the following topics:

Using DBMS_SERVER_ALERT
Summary of DBMS_SERVER_ALERT Subprograms

Using DBMS_SERVER_ALERT

This section contains topics which relate to using the DBMS_SERVER_ALERT package. The following topics define constants used in package procedures.

Object Types
Relational Operators
Supported Metrics

Object Types

You qualify the metric by an individual object for the following object types.

Table 126-1 Object Types Defined as Constants

Constant	Description
`OBJECT_TYPE_SYSTEM`	Metrics collected on the system level for each instance.
`OBJECT_TYPE_FILE`	Metrics collected on the file level. These are used for `AVERAGE_FILE_READ_TIME` and `AVERAGE_FILE_WRITE_TIME` metrics.
`OBJECT_TYPE_SERVICE`	Metrics collected on the service level. Currently `ELAPSED_TIME_PER_CALL` and `CPU_TIME_PER_CALL` are collected.
`OBJECT_TYPE_TABLESPACE`	Metrics collected on the tablespace level.
`OBJECT_TYPE_EVENT_CLASS`	Metrics collected on wait event class level. Currently supported metrics are `AVG_USERS_WAITING` and `DB_TIME_WAITING`.
`OBJECT_TYPE_SESSION`	Metrics collected on the session level. Currently only `BLOCKED_USERS` is collected. The threshold can only be set at the instance level, which means that no object name should be specified when setting the threshold for this type of metric.

Relational Operators

You can specify a relational comparison operator to determine whether or not a given metric's value violates the threshold setting. The server supports the following operators.

Table 126-2 Relational Operators Defined as Constants

Constant	Description
`OPERATOR_CONTAINS`	A metric value matching an entry in a list of threshold values is considered a violation.
`OPERATOR_DO_NOT_CHECK`	The metric value is not compared to the threshold value, and no alerts are generated. Use this operator to disable alerts for a metric.
`OPERATOR_EQ`	A metric value equal to the threshold value is considered a violation.
`OPERATOR_GE`	A metric value greater than or equal to the threshold value is considered a violation.
`OPERATOR_GT`	A metric value greater than the threshold value is considered a violation.
`OPERATOR_LE`	A metric value less than or equal to the threshold value is considered a violation.
`OPERATOR_LT`	A metric value less than the threshold value is considered a violation.
`OPERATOR_NE`	A metric value not equal to the threshold value is considered a violation.

Supported Metrics

The following metrics are supported. All internal metric names are supplied as package constants.

Table 126-3 List of Supported Metrics

Metric Name (Internal)	Metric Name (External)	Units
`SQL_SRV_RESPONSE_TIME`	Service Response (for each execution)	Seconds
`BUFFER_CACHE_HIT`	Buffer Cache Hit (%)	% of cache accesses
`LIBRARY_CACHE_HIT`	Library Cache Hit (%)	% of cache accesses
`LIBRARY_CACHE_MISS`	Library Cache Miss (%)	% of cache accesses
`MEMORY_SORTS_PCT`	Sorts in Memory (%)	% of sorts
`REDO_ALLOCATION_HIT`	Redo Log Allocation Hit	% of redo allocations
`TRANSACTION_RATE`	Number of Transactions (for each second)	Transactions for each Second
`PHYSICAL_READS_SEC`	Physical Reads (for each second)	Reads for each Second
`PHYSICAL_READS_TXN`	Physical Reads (for each transaction)	Reads for each Transaction
`PHYSICAL_WRITES_SEC`	Physical Writes (for each second)	Writes for each Second
`PHYSICAL_WRITES_TXN`	Physical Writes (for each transaction)	Writes for each Transaction
`PHYSICAL_READS_DIR_SEC`	Direct Physical Reads (for each second)	Reads for each Second
`PHYSICAL_READS_DIR_TXN`	Direct Physical Reads (for each transaction)	Reads for each Transaction
`PHYSICAL_WRITES_DIR_SEC`	Direct Physical Writes (for each second)	Writes for each Second
`PHYSICAL_WRITES_DIR_TXN`	Direct Physical Writes (for each transaction)	Writes for each Transaction
`PHYSICAL_READS_LOB_SEC`	Direct LOB Physical Reads (for each second)	Reads for each Second
`PHYSICAL_READS_LOB_TXN`	Direct LOB Physical Reads (for each transaction)	Reads for each Transaction
`PHYSICAL_WRITES_LOB_SEC`	Direct LOB Physical Writes (for each second)	Writes for each Second
`PHYSICAL_WRITES_LOB_TXN`	Direct LOB Physical Writes (for each transaction)	Writes for each Transaction
`REDO_GENERATED_SEC`	Redo Generated (for each second)	Redo Bytes for each Second
`REDO_GENERATED_TXN`	Redo Generated (for each transaction)	Redo Bytes for each Transaction
`DATABASE_WAIT_TIME`	Database Wait Time (%)	% of all database time
`DATABASE_CPU_TIME`	Database CPU Time (%)	% of all database time
`LOGONS_SEC`	Cumulative Logons (for each second)	Logons for each Second
`LOGONS_TXN`	Cumulative Logons (for each transaction)	Logons for each Transaction
`LOGONS_CURRENT`	Current Number of Logons	Number of Logons
`OPEN_CURSORS_SEC`	Cumulative Open Cursors (for each second)	Cursors for each Second
`OPEN_CURSORS_TXN`	Cumulative Open Cursors (for each transaction)	Cursors for each Transaction
`OPEN_CURSORS_CURRENT`	Current Number of Cursors	Number of Cursors
`USER_COMMITS_SEC`	User Commits (for each second)	Commits for each Second
`USER_COMMITS_TXN`	User Commits (for each transaction)	Commits for each Transaction
`USER_ROLLBACKS_SEC`	User Rollbacks (for each second)	Rollbacks for each Second
`USER_ROLLBACKS_TXN`	User Rollbacks (for each transaction)	Rollbacks for each Transaction
`USER_CALLS_SEC`	User Calls (for each second)	Calls for each Second
`USER_CALLS_TXN`	User Calls (for each transaction)	Calls for each Transaction
`RECURSIVE_CALLS_SEC`	Recursive Calls (for each second)	Calls for each Second
`RECURSIVE_CALLS_TXN`	Recursive Calls (for each transaction)	Calls for each Transaction
`SESS_LOGICAL_READS_SEC`	Session Logical Reads (for each second)	Reads for each Second
`SESS_LOGICAL_READS_TXN`	Session Logical Reads (for each transaction)	Reads for each Transaction
`DBWR_CKPT_SEC`	DBWR Checkpoints (for each second)	Checkpoints for each Second
`LOG_SWITCH_SEC`	Background Checkpoints (for each second)	Checkpoints for each Second
`REDO_WRITES_SEC`	Redo Writes (for each second)	Writes for each Second
`REDO_WRITES_TXN`	Redo Writes (for each transaction)	Writes for each Transaction
`LONG_TABLE_SCANS_SEC`	Scans on Long Tables (for each second)	Scans for each Second
`LONG_TABLE_SCANS_TXN`	Scans on Long Tables (for each transaction)	Scans for each Transaction
`TOTAL_TABLE_SCANS_SEC`	Total Table Scans (for each second)	Scans for each Second
`TOTAL_TABLE_SCANS_TXN`	Total Table Scans (for each transaction)	Scans for each Transaction
`FULL_INDEX_SCANS_SEC`	Fast Full Index Scans (for each second)	Scans for each Second
`FULL_INDEX_SCANS_TXN`	Fast Full Index Scans (for each transaction)	Scans for each Transaction
`TOTAL_INDEX_SCANS_SEC`	Total Index Scans (for each second)	Scans for each Second
`TOTAL_INDEX_SCANS_TXN`	Total Index Scans (for each transaction)	Scans for each Transaction
`TOTAL_PARSES_SEC`	Total Parses (for each second)	Parses for each Second
`TOTAL_PARSES_TXN`	Total Parses (for each transaction)	Parses for each Transaction
`HARD_PARSES_SEC`	Hard Parses (for each second)	Parses for each Second
`HARD_PARSES_TXN`	Hard Parses (for each transaction)	Parses for each Transaction
`PARSE_FAILURES_SEC`	Parse Failures (for each second)	Parses for each Second
`PARSE_FAILURES_TXN`	Parse Failures (for each transaction)	Parses for each Transaction
`DISK_SORT_SEC`	Sorts to Disk (for each second)	Sorts for each Second
`DISK_SORT_TXN`	Sorts to Disk (for each transaction)	Sorts for each Transaction
`ROWS_PER_SORT`	Rows Processed for each Sort	Rows for each Sort
`EXECUTE_WITHOUT_PARSE`	Executes Performed Without Parsing	% of all executes
`SOFT_PARSE_PCT`	Soft Parse (%)	% of all parses
`CURSOR_CACHE_HIT`	Cursor Cache Hit (%)	% of soft parses
`USER_CALLS_PCT`	User Calls (%)	% of all calls
`TXN_COMMITTED_PCT`	Transactions Committed (%)	% of all transactions
`NETWORK_BYTES_SEC`	Network Bytes, for each second	Bytes for each Second
`RESPONSE_TXN`	Response (for each transaction)	Seconds for each Transaction
`DATA_DICT_HIT`	Data Dictionary Hit (%)	% of dictionary accesses
`DATA_DICT_MISS`	Data Dictionary Miss (%)	% of dictionary accesses
`SHARED_POOL_FREE_PCT`	Shared Pool Free(%)	% of shared pool
`AVERAGE_FILE_READ_TIME`	Average File Read Time	Microseconds
`AVERAGE_FILE_WRITE_TIME`	Average File Write Time	Microseconds
`DISK_IO`	Disk I/O	Milliseconds
`PROCESS_LIMIT_PCT`	Process Limit Usage (%)	% of maximum value
`SESSION_LIMIT_PCT`	Session Limit Usage (%)	% of maximum value
`USER_LIMIT_PCT`	User Limit Usage (%)	% of maximum value
`AVG_USERS_WAITING`	Average Number of Users Waiting on a Class of Wait Events	Count of sessions
`DB_TIME_WAITING`	Percent of Database Time Spent Waiting on a Class of Wait Events	% of Database Time
`APPL_DESGN_WAIT_SCT`	Application Design Wait (by session count)	Count of sessions
`APPL_DESGN_WAIT_TIME`	Application Design Wait (by time)	Microseconds
`PHYS_DESGN_WAIT_SCT`	Physical Design Wait (by session count)	Count of sessions
`PHYS_DESGN_WAIT_TIME`	Physical Design Wait (by time)	Microseconds
`CONTENTION_WAIT_SCT`	Internal Contention Wait (by session count)	Count of sessions
`CONTENTION_WAIT_TIME`	Internal Contention Wait (by time)	Microseconds
`PSERVICE_WAIT_SCT`	Process Service Wait (by session count)	Count of sessions
`PSERVICE_WAIT_TIME`	Process Service Wait (by time)	Microseconds
`NETWORK_MSG_WAIT_SCT`	Network Message Wait (by session count)	Count of sessions
`NETWORK_MSG_WAIT_TIME`	Network Message Wait (by time)	Microseconds
`DISK_IO_WAIT_SCT`	Disk I/O Wait (by session count)	Count of sessions
`OS_SERVICE_WAIT_SCT`	Operating System Service Wait (by session count)	Count of sessions
`OS_SERVICE_WAIT_TIME`	Operating System Service Wait (by time)	Microseconds
`DBR_IO_LIMIT_WAIT_SCT`	Resource Mgr I/O Limit Wait (by session count)	Count of sessions
`DBR_IO_LIMIT_WAIT_TIME`	Resource Mgr I/O Limit Wait (by time)	Microseconds
`DBR_CPU_LIMIT_WAIT_SCT`	Resource Mgr CPU Limit Wait (by session count)	Count of sessions
`DBR_CPU_LIMIT_WAIT_TIME`	Resource Mgr CPU Limit Wait (by time)	Microseconds
`DBR_USR_LIMIT_WAIT_SCT`	Resource Mgr User Limit Wait (by session count)	Count of sessions
`DBR_USR_LIMIT_WAIT_TIME`	Resource Mgr User Limit Wait (by time)	Microseconds
`OS_SCHED_CPU_WAIT_SCT`	Operating System Scheduler CPU Wait (by session count)	Count of sessions
`OS_SCHED_CPU__WAIT_TIME`	Operating System Scheduler CPU Wait (by time)	Microseconds
`CLUSTER_MSG_WAIT_SCT`	Cluster Messaging Wait (by session count)	Count of sessions
`CLUSTER_MSG_WAIT_TIME`	Cluster Messaging Wait (by time)	Microseconds
`OTHER_WAIT_SCT`	Other Waits (by session count)	Count of sessions
`OTHER_WAIT_TIME`	Other Waits (by time)	Microseconds
`ENQUEUE_TIMEOUTS_SEC`	Enqueue Timeouts (for each second)	Timeouts for each Second
`ENQUEUE_TIMEOUTS_TXN`	Enqueue Timeouts (for each transaction)	Timeouts for each Transaction
`ENQUEUE_WAITS_SEC`	Enqueue Waits (for each second)	Waits for each Second
`ENQUEUE_WAITS_TXN`	Enqueue Waits (for each transaction)	Waits for each Transaction
`ENQUEUE_DEADLOCKS_SEC`	Enqueue Deadlocks (for each second)	Deadlocks for each Second
`ENQUEUE_DEADLOCKS_TXN`	Enqueue Deadlocks (for each transaction)	Deadlocks for each Transaction
`ENQUEUE_REQUESTS_SEC`	Enqueue Requests (for each second)	Requests for each Second
`ENQUEUE_REQUESTS_TXN`	Enqueue Requests (for each transaction)	Requests for each Transaction
`DB_BLKGETS_SEC`	DB Block Gets (for each second)	Gets for each Second
`DB_BLKGETS_TXN`	DB Block Gets (for each transaction)	Gets for each Transaction
`CONSISTENT_GETS_SEC`	Consistent Gets (for each second)	Gets for each Second
`CONSISTENT_GETS_TXN`	Consistent Gets (for each transaction)	Gets for each Transaction
`DB_BLKCHANGES_SEC`	DB Block Changes (for each second)	Changes for each Second
`DB_BLKCHANGES_TXN`	DB Block Changes (for each transaction)	Changes for each Transaction
`CONSISTENT_CHANGES_SEC`	Consistent Changes (for each second)	Changes for each Second
`CONSISTENT_CHANGES_TXN`	Consistent Changes (for each transaction)	Changes for each Transaction
`SESSION_CPU_SEC`	Database CPU (for each second)	Microseconds for each Second
`SESSION_CPU_TXN`	Database CPU (for each transaction)	Microseconds for each Transaction
`CR_BLOCKS_CREATED_SEC`	CR Blocks Created (for each second)	Blocks for each Second
`CR_BLOCKS_CREATED_TXN`	CR Blocks Created (for each transaction)	Blocks for each Transaction
`CR_RECORDS_APPLIED_SEC`	CR Undo Records Applied (for each second)	Records for each Second
`CR_RECORDS_APPLIED_TXN`	CR Undo Records Applied (for each transaction)	Records for each Transaction
`RB_RECORDS_APPLIED_SEC`	Rollback Undo Records Applied (for each second)	Records for each Second
`RB_RECORDS_APPLIED_TXN`	Rollback Undo Records Applied (for each transaction)	Records for each Transaction
`LEAF_NODE_SPLITS_SEC`	Leaf Node Splits (for each second)	Splits for each Second
`LEAF_NODE_SPLITS_TXN`	Leaf Node Splits (for each transaction)	Splits for each Transaction
`BRANCH_NODE_SPLITS_SEC`	Branch Node Splits (for each second)	Splits for each Second
`BRANCH_NODE_SPLITS_TXN`	Branch Node Splits (for each transaction)	Splits for each Transaction
`GC_BLOCKS_CORRUPT`	Global Cache Blocks Corrupt	Blocks
`GC_BLOCKS_LOST`	Global Cache Blocks Lost	Blocks
`GC_AVG_CR_GET_TIME`	Global Cache CR Request	Milliseconds
`GC_AVG_CUR_GET_TIME`	Global Cache Current Request	Milliseconds
`PX_DOWNGRADED_SEC`	Downgraded Parallel Operations (for each second)	Operations for each Second
`PX_DOWNGRADED_25_SEC`	Downgraded to 25% and more (for each second)	Operations for each Second
`PX_DOWNGRADED_50_SEC`	Downgraded to 50% and more (for each second)	Operations for each Second
`PX_DOWNGRADED_75_SEC`	Downgraded to 75% and more (for each second)	Operations for each Second
`PX_DOWNGRADED_SER_SEC`	Downgraded to serial (for each second)	Operations for each Second
`BLOCKED_USERS`	Number of Users blocked by some Session	Number of Users
`PGA_CACHE_HIT`	PGA Cache Hit (%)	% bytes processed in PGA
`ELAPSED_TIME_PER_CALL`	Elapsed time for each user call for each service	Microseconds for each call
`CPU_TIME_PER_CALL`	CPU time for each user call for each service	Microseconds for each call
`TABLESPACE_PCT_FULL`	Tablespace space usage	% full
`TABLESPACE_BYT_FREE`	Tablespace bytes space usage	Kilobytes free

Summary of DBMS_SERVER_ALERT Subprograms

Table 126-4 DBMS_SERVER_ALERT Package Subprograms

Subprogram	Description
EXPAND_MESSAGE Function	Expands alert messages
GET_THRESHOLD Procedure	Gets the current threshold settings for a specified metric
SET_THRESHOLD Procedure	Sets the warning and critical thresholds for a specified metric

EXPAND_MESSAGE Function

This function expands alert messages.

Syntax

DBMS_SERVER_ALERT.EXPAND_MESSAGE(
   user_language            IN   VARCHAR2,
   message_id               IN   NUMBER,
   argument_1               IN   VARCHAR2,
   argument_2               IN   VARCHAR2,
   argument_3               IN   VARCHAR2,
   argument_4               IN   VARCHAR2,
   argument_5               IN   VARCHAR2)
  RETURN VARCHAR2;

Parameters

Table 126-5 EXPAND_MESSAGE Function Parameters

Parameter	Description
`user_language`	The language of the current session.
`message_id`	Id of the alert message
`argument_1`	The first argument in the alert message.
`argument_2`	The second argument in the alert message.
`argument_3`	The third argument in the alert message.
`argument_4`	The fourth argument in the alert message.
`argument_5`	The fifth argument in the alert message.

GET_THRESHOLD Procedure

This procedure gets the current threshold settings for the specified metric.

Syntax

DBMS_SERVER_ALERT.GET_THRESHOLD(
   metrics_id               IN   BINARY_INTEGER,
   warning_operator         OUT  BINARY_INTEGER,
   warning_value            OUT  VARCHAR2,
   critical_operator        OUT  BINARY_INTEGER,
   critical_value           OUT  VARCHAR2,
   observation_period       OUT  BINARY_INTEGER,
   consecutive_occurrences  OUT  BINARY_INTEGER,
   instance_name            IN   VARCHAR2,
   object_type              IN   BINARY_INTEGER,
   object_name              IN   VARCHAR2);

Parameters

Table 126-6 GET_THRESHOLD Procedure Parameters

Parameter	Description
`metrics_id`	The internal name of the metric. See "Supported Metrics".
`warning_operator`	The operator for the compa3ring the actual value with the warning threshold.
`warning_value`	The warning threshold value.
`critical_operator`	The operator for the comparing the actual value with the critical threshold.
`critical_value`	The critical threshold value.
`observation_period`	The period at which the metric values are computed and verified against the threshold setting.
`consecutive_occurrences`	The number of observation periods the metric value should violate the threshold value before the alert is issued.
`instance_name`	The name of the instance for which the threshold is set. This is `NULL` for database-wide alerts. In cases in which this parameter is not `NULL`, this should be set to one of the `INSTANCE_NAME` values found in the `GV$INSTANCE` View.
`object_type`	Either `OBJECT_TYPE_SYSTEM` or `OBJECT_TYPE_SERVICE`.
`object_name`	The name of the object.

Usage Notes

Note that this subprogram does not check if the value of the instance_name parameter is meaningful or valid.

SET_THRESHOLD Procedure

This procedure sets the warning and critical thresholds for a specified metric.

Syntax

DBMS_SERVER_ALERT.SET_THRESHOLD(
   metrics_id               IN   BINARY_INTEGER,
   warning_operator         IN   BINARY_INTEGER,
   warning_value            IN   VARCHAR2,
   critical_operator        IN   BINARY_INTEGER,
   critical_value           IN   VARCHAR2,
   observation_period       IN   BINARY_INTEGER,
   consecutive_occurrences  IN   BINARY_INTEGER,
   instance_name            IN   VARCHAR2,
   object_type              IN   BINARY_INTEGER,
   object_name              IN   VARCHAR2);

Parameters

Table 126-7 SET_THRESHOLD Procedure Parameters

Parameter	Description
`metrics_id`	The internal name of the metric. See "Supported Metrics".
`warning_operator`	The operator for the comparing the actual value with the warning threshold (such as `OPERATOR_GE`). See "Relational Operators".
`warning_value`	The warning threshold value. This is `NULL` if no warning threshold is set. A list of values may be specified for `OPERATOR_CONTAINS`.
`critical_operator`	The operator for the comparing the actual value with the critical threshold. See "Relational Operators".
`critical_value`	The critical threshold value. This is `NULL` if not set. A list of values may be specified for `OPERATOR_CONTAINS`.
`observation_period`	The period at which the metric values are computed and verified against the threshold setting. The valid range is 1 to 60 minutes.
`consecutive_occurrences`	The number of observation periods the metric value should violate the threshold value before the alert is issued.
`instance_name`	The name of the instance for which the threshold is set. This is `NULL` for database-wide alerts.
`object_type`	See "Object Types".
`object_name`	The name of the object. This is `NULL` for `SYSTEM`.

Usage Notes

Note that this subprogram does not check if the value of the instance_name parameter is meaningful or valid. Passing a name that does not identify a valid instance will result in a threshold that is not used by any by any instance although the threshold setting will be visible in the DBA_THRESHOLDS view. The exception is the lower-case string 'database_wide' which is semantically equivalent to passing NULL for the instance name, the latter being the preferred usage.