Automatic deletion after a number of seconds. In Cosmos DB it is set per container with DefaultTimeToLive or per item with ttl; in Redis it is set on a key.
Also called time to live.
Read more: Microsoft Learn
In the Ultra Transcenders books
AI-200DP-900SC-300AZ-802DP-800
Each book explains TTL in context, with comparison tables and the common traps.
Terms in this definition
- Cosmos DB
NoSQL database distributed globally, offering writes in multiple regions, automatic indexing and latency below 10 ms.
- Set
Secret permission in Key Vault for writing secrets; some older material refers to it as Create.
- Container
Something that groups data. Blob Storage containers sit inside a storage account and hold blobs much as folders hold files; Cosmos DB containers hold items and set the scope for partitioning and throughput.
- Index field attributes
Settings applied to each field in an Azure AI Search index:
searchablefor full text,retrievableto return it,filterablefor exact-match$filter,sortable,facetablefor counts, andkeyfor the unique document ID.
Related terms
- Dead-letter queue
Each Service Bus queue and subscription automatically has this secondary queue, where messages end up when they can't be delivered or processed. You never create it yourself, message TTL has no effect there, and nothing in it is removed unless you remove it.
- Eviction policy
The Redis setting that decides which keys get dropped once memory runs out. Azure Managed Redis uses volatile-lru by default, which removes only keys carrying a TTL, while RediSearch needs NoEviction.
- Stateful operation
Any Structured Streaming operation that must hold intermediate data between batches (stream-stream joins, deduplication or aggregations over windows, for instance). That data sits in a state store kept with the checkpoint, and TTL, watermarks and time-range conditions keep it from growing endlessly.