SLT replication monitoring

SLT replication monitoring

This monitor is dedicated to the monitoring of SAP LT Replication Server (SLT).
It provides a monitoring equivalent to the replication figures of transaction LTRC.
It discovers the replication configurations defined on the system, then reports for each
replicated table how many changed records are still waiting to be replicated, and how far
behind the table has fallen.

Note: the connector must point to the SLT server, that is the system where transaction LTRC opens. Pointing it at a replication source or target returns no configuration.

Configuration hints

Use the surveillance table to adjust the monitoring settings:
- Thresholds
- Severity
- Filters

Configurations are discovered automatically on every run, so a configuration added in SLT is picked up without changing this monitor.

Latency window

Defines how far back the monitor looks when reading latency, in minutes.
A short window reports the current lag. A long window keeps older peaks in the figures, because the maximum is taken over the whole window.
Default is 60 minutes.
This setting has no effect on the count of unprocessed records, which is always the current value.

Per-occurrence alarm

This option allows to tune the volume of alarms that will be generated:
- If enabled, you will receive one alarm per table over a threshold, with details.
- If disabled, you will only get one alarm per rule, listing the tables that breached.

Send metadata

If enabled, this parameter will send the collected tables as metadata to the configured plugins/integrations
It can usually be retrieved as logs or tabular data within the corresponding integrations
All collected tables are sent, not only those matching a surveillance rule
Configurations that SLT does not support are excluded, as they carry no table data

Surveillance table

Parameter	Description
Active	Use this field to activate or deactivate a line of configuration.
Configuration	A filter to match only a given replication configuration. It is matched against the schema name and the description, so either can be used.
Table	A filter to match only a given replicated table.
Max unprocessed records	The threshold for the number of records waiting to be replicated. An alarm is sent when the count reaches this value. Leave at `0` to disable this check.
Only if not draining	Restricts the above check to backlogs that are not being absorbed. See the note below.
Latency figure	Which latency value the latency threshold applies to: MIN, MAX or MEDIAN. See the mapping below.
Max latency	The threshold for the latency, in seconds. An alarm is sent when the selected figure is above this value. Leave at `0` to disable this check.
Alarm if master job stopped	If checked, an alarm is sent when the master job of the configuration is not running.
Severity	The severity of the alarm.
enable Alarm	If checked, this line of surveillance will be used for alarm generation.
enable QOS	If checked, this line of surveillance will be used for metric generation.

Note: with Only if not draining enabled, an alarm is only raised if the backlog is no smaller than it was at the previous run. A backlog that is shrinking means the replication is catching up, and stays quiet. A backlog that is stable or growing alarms, even if it is not growing, because a backlog frozen at a high value is not being processed. The very first run only records a starting point and raises no alarm on this check.

Note: an absolute threshold alone is rarely usable on its own. A high volume table can sit permanently above any reasonable value while replicating perfectly, and a low volume table may never reach it even when stuck. This is why Only if not draining is enabled by default.

Latency figures

SLT records latency per table and per measurement interval. The monitor uses the most recent interval available within the latency window.

Latency figure	Description
MIN	The lowest latency measured during the interval.
MAX	The highest latency measured during the interval. Catches the worst moment.
MEDIAN	The median latency of the interval. Ignores isolated peaks.

Note: SLT only records a median on its hourly figures. When MEDIAN is selected, the monitor uses the most recent interval that actually carries one. If no interval carries a median, the table reports no latency rather than a latency of zero, and the latency check does not alarm for that table.

Note: latency is only recorded for tables in delta replication. Tables in initial load, or stopped, have no latency figure at all. Such a table is reported without a latency, and is never reported as being up to date. A latency threshold on a table that is not in delta replication can therefore never be reached.

Unsupported configurations

Some replication scenarios are not supported by the SLT programming interface used to count unprocessed records. The call is refused by SAP with an unsupported sender system type, even when the configuration is running normally.
Such a configuration is reported as not monitored, and appears in the monitor log with the reason.
It is deliberately not reported as healthy and does not raise an alarm. It is not a fault, but it must remain visible: a configuration silently skipped would leave a permanently green monitor over a replication that nothing is watching.
Latency is collected through a different interface and may still be available for those configurations.

Alarm content

The alarm message contains the configuration, the table concerned, the value that breached and the threshold it breached.
For a backlog alarm, the count recorded at the previous run is appended when one is available, so the trend can be read from the alarm itself.
A stopped master job raises its own alarm on the configuration, independently of any table threshold.
A configuration that could not be collected, for example when the SLT server cannot reach the source system, raises an alarm carrying the reason.

Examples

Example 1

Active	Configuration	Table	Max unprocessed records	Only if not draining	Latency figure	Max latency	Alarm if master job stopped	Severity	enable Alarm	enable QOS
true	*	*	10000	true	MAX	300	true	MAJOR	true	true

Effect: Sends a MAJOR alarm for each table holding at least 10000 unprocessed records that is not being absorbed, and for each table whose worst latency exceeds 5 minutes. Also alarms if a master job is stopped. Sends the record counts and the maximum latency as metrics.

Example 2

Active	Configuration	Table	Max unprocessed records	Only if not draining	Latency figure	Max latency	Alarm if master job stopped	Severity	enable Alarm	enable QOS
true	ECC_PRD_CFIN_S4P	BKPF	0	true	MEDIAN	60	false	WARNING	true	true

Effect: Sends a WARNING alarm when the median latency of table BKPF in the Central Finance configuration exceeds 1 minute. The backlog check is disabled, and a stopped master job does not alarm on this rule.

Generated metrics

metricId	metricUnit	metricTarget	metricDescription
SLT_UNPROCESSED_RECORDS	Records	[CONFIGURATION][TABLE]	Sends the number of records waiting to be replicated, per configuration and table.
SLT_LATENCY	Seconds	[CONFIGURATION][TABLE][STATISTIC]	Sends the latency of the table, per configuration and table. The STATISTIC target records which figure was sent, so a series is never ambiguous.

Note: only the latency figure selected on the surveillance line is sent, not all three. A replication configuration can carry several hundred tables, and sending the minimum, maximum and median for each would triple an already large number of series.

Note: metrics are sent from the first run even when no threshold is configured. This is intentional, so the normal range of a system can be observed before choosing thresholds.

Note: a table with no value for a metric is not sent, rather than being sent as zero. This applies to the latency of tables that are not in delta replication.

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