---
title: Predicate Details
description: Predicate Details

url: https://help.qmonitor.app/docs/features/issues/predicate-details/index.md
lastmod: 2026-09-28T17:58:04+02:00
---


This page contains a form to view and edit all properties of a predicate,
including scoped overrides and the evaluation expressions used by the
background engine.

Scope controls
- Server Tag: apply this predicate only to servers that have the selected tag.
- Server Group: limit the predicate to servers belonging to a specific group.
- Server: target a single SQL instance for this override.
- Database: restrict the predicate to a particular database.
- Object: restrict the predicate to a specific object (for example, a file,
  table, or index).
- Use the scope controls to create a scoped override; leaving a field empty
  makes the override less specific (broader).

Editable expressions and fields
- Evaluation Expression: the boolean expression the engine evaluates. The
  default is "actual = expected", but you can change this to any valid
  expression supported by the engine (for example "actual < expected" or
  "actual > low AND actual < high").
- Expected Expression: the expected value or expression to compare against.
  This may be a constant (e.g., 20), a computed expression, or one of the
  available properties of the object being checked.
- Actual Expression: the expression that yields the measured value to be
  evaluated (typically the name of a property from the underlying object,
  e.g., free_percent or file_size_gb).
- Property Name: the logical name used to identify the property in UIs and
  reports. It maps the actual expression to a friendly identifier and can be
  used by other parts of the system to reference this value (for example in
  charts or exported data).
- Filter Expression: an optional expression that narrows the set of objects
  the predicate applies to. Use it to include or exclude specific objects so
  the check only runs against matching items (for example: database_name = 'X'
  AND file_type = 'log').

Behavior and helpers
- Save applies the changes and creates or updates an override for the selected
  scope. Changing any property (including disabling) counts as an override.