Fallback

In the Ultra Transcenders books

DBX-GENAI

Each book explains Fallback in context, with comparison tables and the common traps.

Terms in this definition

• LIKE

  Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.

• Unity Gateway

  Governs AI spending, security and access from one Databricks control plane, spanning agents, MCP servers and models. Only a portion applies to system.ai model services, including budgets and usage tracking.

• FIRST

  A DAX function available only inside visual calculations. It fetches the value at the start of one axis of the visual's matrix, which makes it handy for comparing each point with the first; its opposite is LAST.

• Traffic splitting

  A Container Apps capability, configured in configuration.ingress.traffic, that gives revisions percentage weights adding up to 100%, picking each revision by name or by label.

Related terms

• ATS+SCSI

  Locking mode for VMFS with a fallback: it starts with ATS, then uses SCSI reservations, holding an entire device while metadata changes. Seen on VMFS5 upgraded from VMFS3, and on new datastores where devices lack ATS.

• Cold migration

  Relocating a VM that is powered off or suspended to a different host or datastore. Because fewer target requirements are checked than for vMotion, it is the documented fallback when vMotion checks stop a machine from moving.

• Custom variables

  Values you define once in a Declarative Automation Bundle, under variables, and reuse anywhere as ${var.<name>}. A variable can carry a fallback value, fetch an object's ID by lookup, or be declared type: complex, and everything is filled in when you deploy.

• DirectLakeBehavior

  A property of a semantic model that decides how Direct Lake on SQL handles DirectQuery fallback. Automatic, the default, switches over quietly; DirectLakeOnly raises an error; DirectQueryOnly always uses DirectQuery. Direct Lake on OneLake ignores it.

• Fallback domain

  When a Microsoft 365 organisation signs up, it gets an onmicrosoft.com domain that serves as the default for usernames and mail routing. You can switch the fallback role to a different onmicrosoft.com domain, but these domains can never be deleted and each tenant may hold at most five of them.

• Global (Org-wide default) policy

  In Teams, the fallback policy for each policy type, which covers anyone who has not been given a policy of that type directly or through a group. If several could apply, a direct assignment takes precedence, followed by the group assignment with the highest rank.

• IFERROR

  Catches an error in a DAX expression and returns a fallback value. Like ISERROR it triggers additional storage engine scans, so cleaning data upstream in Power Query, testing with IF, or calling DIVIDE are better options.

• Just-in-time protection

  An Endpoint DLP capability that holds back, or audits, attempts to move files out of a device when the file has never been classified or its classification is out of date, until the policy check finishes. If that check fails, a fallback action applies.