OAP(Observability Analysis Platform) is a new concept, which starts in SkyWalking 6.x. OAP replaces the old SkyWalking whole backend. The capabilities of the platform are following.
OAP accepts data from more sources, which belongs two groups: Tracing and Metrics.
At the same time by using any integration solution provided, such as SkyWalking log plugin or toolkits, SkyWalking provides visualization integration for binding tracing and logging together by using the trace id and span id.
As usual, all services provided by gRPC and HTTP protocol to make integration easier for unsupported ecosystem.
Tracing in OAP has two ways to process.
Also, SkyWalking accepts trace formats from other project, such as Zipkin, Jaeger, OpenCensus. These formats could be processed in the two ways too.
Metrics in OAP is totally new feature in 6 series. Build observability for a distributed system based on metrics of connected nodes. No tracing data is required.
Metrics data are aggregated inside OAP cluster in streaming mode. See about Observability Analysis Language, which provides the easy way to do aggregation and analysis in script style.