Short for the acknowledgement flag in TCP. A target that returns it on the chosen port passes a load balancer's TCP health check.
Also called acknowledgement.
In the Ultra Transcenders books
Each book explains ACK in context, with comparison tables and the common traps.
Terms in this definition
- TCP
A transport protocol that is connection-oriented.
- RETURNS
States what a function gives back, as a type or a table, inside
CREATE FUNCTION. SQL functions can leave it out and have the type worked out from their body. - ELT
Extract, load, transform: raw data lands in the target system first and is transformed there. See ETL for the opposite order.
- Health check
An App Service feature that calls a chosen path on every instance and takes any instance that fails out of the load balancer's rotation.
Related terms
- RST
Cuts off a TCP connection at once. Once an ACK arrives, load balancer health probes over TCP send this flag to finish.
- SYN
Marks the start of a TCP connection. Load balancers probing a port send this flag and consider the target healthy if an ACK returns.
- TLB
Memory page translations are cached in this part of a processor. If a purple screen says Failed to ack TLB invalidate, one physical CPU failed during the clearing of these entries.