Structure

Complete YAML structure reference for Sling monitor configuration files

Below is the structure of the monitor configuration file.

Root Level

At the root level, a monitor configuration accepts the following keys:

# 'connection' and 'objects' keys are required
connection: <connection name>

defaults: <monitor object config>

objects:
  <object name or pattern>: <monitor object config>

schemata:
  enabled: true | false
  exclude: [<glob patterns>]

Object Configuration

The <object name or pattern> identifies the table or view to monitor. This can be a fully qualified name (e.g., public.users), or a wildcard pattern using * and ? (e.g., public.*, analytics.fact_*).

The <monitor object config> accepts the following keys:

# Object-level metrics
disabled: true | false
metadata: true | false
row_count: true | false
body_md5: true | false

# Freshness
freshness_threshold: <duration string>
freshness_column: <column name>

# Anomaly detection tuning
anomaly_detection:
  z_score_threshold: <float>
  min_history_points: <int>
  min_history_days: <int>
  history_days: <int>

# Alert triggers
alert_on_change:
  - name | type | timestamp | size | body | count

# Column-level monitoring
columns:
  <column name or "*">: <monitor column config>

Column Configuration

The <monitor column config> accepts the following keys:

# Statistics
count: true | false
null_count: true | false
count_distinct: true | false
unique_count: true | false
size: true | false
min_max_mean: true | false
min_max_len: true | false
percentile: true | false

# Validation
regex_match:
  - <regex pattern>
regex_not_match:
  - <regex pattern>
accepted_values:
  - <value>
rejected_values:
  - <value>

# Alert triggers
alert_on_change:
  - name | type | timestamp | size | body | count

Schemata Configuration

The schemata block controls schema change detection across the monitored connection:

schemata:
  enabled: true
  exclude:
    - "temp_schema.*"
    - "*.staging_*"

Key	Type	Default	Description
enabled	bool	false	Enable schema change detection
exclude	string[]	["*.*_tmp"]	Glob patterns for objects to exclude from schema tracking

When exclude is not set, the default pattern ["*.*_tmp"] is applied automatically. Set exclude: [] (empty array) to disable all exclusions.

Configuration Reference

Object-Level Keys

Key	Type	Default	Description
disabled	bool	false	Exclude this object from monitoring
metadata	bool	false	Collect schema info (columns, types). Required for schema change detection
row_count	bool	false	Count total rows
body_md5	bool	false	Track MD5 hash of view/procedure definitions
freshness_threshold	string	—	Maximum data age before staleness alert (e.g., "24h", "7d")
freshness_column	string	—	Column to query MAX() for data age
anomaly_detection	object	—	Override anomaly detection parameters
alert_on_change	string[]	—	Change types that trigger alerts
columns	map	—	Column-level monitoring configuration

Column-Level Keys

Key	Type	Default	Description
count	bool	false	Non-null and null value counts
null_count	bool	false	Null value count
count_distinct	bool	false	Unique value count (cardinality)
unique_count	bool	false	Unique value count
size	bool	false	Total size in bytes
min_max_mean	bool	false	Minimum, maximum, and mean for numeric columns
min_max_len	bool	false	Minimum and maximum string length for text columns
percentile	bool	false	Percentile statistics (p50, p90, p95, p99) and standard deviation
regex_match	string[]	—	Patterns that values should match
regex_not_match	string[]	—	Patterns that values should NOT match
accepted_values	string[]	—	Valid values (anything else is a violation)
rejected_values	string[]	—	Values that should not appear
alert_on_change	string[]	—	Change types that trigger alerts

Anomaly Detection Keys

Key	Type	Default	Description
z_score_threshold	float	3.0	Z-score threshold for anomaly detection
min_history_points	int	7	Minimum data points required before detection begins
min_history_days	int	7	Minimum days of history required
history_days	int	30	Lookback window in days for baseline calculation

Wildcards & Patterns

Use * and ? wildcards in object names to monitor multiple objects with the same configuration:

• * matches any sequence of characters

• ? matches a single character

objects:
  # All tables in public schema
  public.*:
    metadata: true
    row_count: true

  # Fact tables in analytics schema
  analytics.fact_*:
    row_count: true
    freshness_threshold: "6h"

  # Single character wildcard
  staging.tmp_?:
    metadata: true

Use "*" as a column name in defaults to apply column metrics to all columns:

defaults:
  columns:
    "*":
      null_count: true
      count_distinct: true

Definition Order

Objects are processed in definition order. When a wildcard expands to include a table and a later entry targets that same table, the later entry's configuration wins entirely.

Exclude specific tables from a wildcard:

objects:
  # Monitor all public tables...
  public.*:
    metadata: true
    row_count: true

  # ...except these
  public.sensitive_table:
    disabled: true
  public.audit_logs:
    disabled: true

Disable all, then re-enable specific tables:

objects:
  public.*:
    disabled: true

  public.users:
    metadata: true
    row_count: true
  public.orders:
    row_count: true
    freshness_threshold: "12h"

Definition order matters: when a wildcard expands to include a table, and a later entry targets that same table, the later entry's configuration wins entirely.

Defaults Inheritance

Settings defined under defaults are applied to all objects. Individual objects can override any default value.

connection: MY_POSTGRES

defaults:
  metadata: true
  row_count: true
  freshness_threshold: "24h"
  columns:
    "*":
      null_count: true

objects:
  public.users: {}              # inherits all defaults
  public.orders:
    freshness_threshold: "6h"   # overrides default threshold
    columns:
      total:
        min_max_mean: true      # adds to inherited column config
  public.staging:
    disabled: true              # excluded entirely