Resource group service

Introduction

The Performance Schema Resource Group service provides methods to:

• assign a resource group name to a foreground (user) and background (system) threads
• query the system attributes of a given thread, such as thread id, user name, host name, etc.

Once assigned, the resource group name is visible in the PERFORMANCE_SCHEMA.THREADS table.

Setting a group name

A group name can be assigned to the current thread or to another thread identified by either a thread id or a pointer to thread instrumentation.

User-defined data can also be assigned to the thread.

To assign a group name to the current thread, use:

int set_thread_resource_group(const char* group_name,
                              int group_name_len,
                              void *user_data)

where

• group_name is the resource group name string
• group_name_len is the length of resource group name string
• user_data is an optional user-defined context

To assign a group name and user data to another thread, use:

int set_thread_resource_group_by_id(PSI_thread *psi_thread,
                                    unsigned long long thread_id,
                                    const char* group_name,
                                    int group_name_len,
                                    void *user_data)

where

• psi_thread is the target thread instrumentation. Ignored if NULL.
• thread_id is the thread id of the target thread (THREADS.THREAD_ID). Only used if thread is NULL.
• group_name is the resource group name string
• group_name_len is the length of resource group name string
• user_data is the optional user-defined context

Both functions return 0 if successful, or 1 otherwise.

The group name is limited to 64 characters, UTF8. Names longer than 64 characters will be truncated. user_data is an optional user-defined context associated with thread_id that will be returned to the callback function in the thread attributes structure.

Getting thread attributes

To get the system and security attributes for the current thread, use:

int get_thread_system_attrs(PSI_thread_attrs *thread_attrs)

where

• thread_attrs is a pointer to a thread attribute structure PSI_thread_attrs

To get the system and security attributes for another thread identified either by a thread id or by the thread instrumentation, use:

int get_thread_system_attrs_by_id(PSI_thread *psi_thread,
                                  unsigned long long thread_id,
                                  PSI_thread_attrs *thread_attrs)

where psi_thread is the target thread instrumentation. Ignored if NULL. thread_id is the thread id of the target thread (THREADS.THREAD_ID). Only used if psi_thread is NULL. thread_attrs is a pointer to thread attribute structure, PSI_thread_attrs

Both function return 0 if successful or 1 otherwise.