ygerzhedovich commented on code in PR #2726: URL: https://github.com/apache/ignite-3/pull/2726#discussion_r1366778059
########## modules/system-view-api/README.md: ########## @@ -0,0 +1,127 @@ +# System view API module + +System Views, also known as virtual tables, is a powerful tool that is meant to expose the system's state and provide real-time +insights into its various components. + +This module provides an abstraction and core interfaces for the Ignite system views. + +## Base components description + +* `SystemViews` provides static factory methods for system view builders. +* `SystemView` is a base class for system view definitions. + * `ClusterSystemView` represents cluster-wide view definition. This type of view is used to expose the data from a common source, + like distributed meta storage, table, or anything, so every node will provide the same copy of dataset. + Use `SystemViews.clusterViewBuilder()` to create this type of view. + * `NodeSystemView` represents node view definition. This type of view is used to expose data that is unique to a particular node, + and can be acquired only on the node itself. Note that a special column containing local node name always implicitly added to + the local view. The name of this column must be set explicitly using the `nodeNameColumnAlias` builder method. + Use `SystemViews.nodeViewBuilder()` to create this type of view. +* `SystemViewProvider` denotes a component that provides system views. +* `SystemViewManager` is responsible for views registration in the cluster. + +## Basic concepts + +* Component that want to expose system views must extend `SystemViewProvider` interface. +* All system views must be registered during node startup. +* All system views are reside in `SYSTEM` schema. +* From SQL perspective, a system view is a virtual immutable table. +* System views doesn't support transactions. Review Comment: let's clarify what does it mean. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@ignite.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
