RoleManager.FindByNameAsync与IdentityServer数据库调用关联及性能排查

• 维护一个采用IdentityServer进行身份认证的站点，近期发现站点偶尔出现卡顿，通过AppInsights定位到调用RoleManager.FindByNameAsync(name)的端点存在随机变慢的情况。
• AppInsights显示该方法触发的SQL查询如下：

SELECT [t].[Id], [t].[Email], [t].[FirstName], [t].[LastName], [t].[UserName], [t].[CreatedAtUtc] AS [CreatedAt], [t].[EmailConfirmed], [t].[LastLoginUtc] AS [LastLogin], [t].[LockoutEnabled], [t].[LockoutEnd] AS [LockoutEndDateUtc], [claim].[ClaimType] AS [Type], [claim].[ClaimValue] AS [Value], [claim].[Id] AS [Id0]
FROM [UserClaims] AS [claim]
INNER JOIN (
    SELECT [user].*
    FROM [Users] AS [user]
    WHERE [user].[Id] IN (
        SELECT [claim0].[UserId]
        FROM [UserClaims] AS [claim0]
        WHERE ([claim0].[ClaimType] = @__type_0) AND ([claim0].[ClaimValue] = @__value_1)
    )
) AS [t] ON [claim].[UserId] = [t].[Id]

• 经确认，数据库查询本身耗时不长（最多100ms），因此推测卡顿问题出在C#代码层面。
• 核心疑问：RoleManager.FindByNameAsync是如何与IdentityServer集成的？RoleManager属于微软官方扩展组件，但在站点配置中未找到二者的关联设置（本人接触IdentityServer时间不长）。

内容的提问来源于stack exchange，提问作者daxu