This interface is provided to plugins/components, using which they can expose their tables in performance schema.

This interface consists of mainly two structures

PFS_engine_table_proxy
This structure is collection of function pointers which are to be implemented by plugins/components who wish to expose table in performance_schema.

Control flow will be redirected to these functions' implementations when query reaches to Performance Schema storage engine to perform some operation on the table added by plugin/component.
PFS_engine_table_share_proxy
An instance of this structure is to keep the required information which would be used to register a table in performance_schema. Table share, for the table added by plugin/component, in performance schema would be initialized using this instance and it would be provided by plugin/component while registering table.

Plugin/component is responsible to maintain buffers which would be used to store table data. During insert/fetch/delete etc, these buffers will be used.

Diagram

Following flow diagram shows the execution of a select query executed on a table which is added in performance schema by plugin/component.