Custom Dimension is over writing the existing value rather than creating a new row

Hi Support,

I used custom dimension plugin & created a custom dimension in my website. I integrated it with JS tracking client.

I am storing session id into custom dimension and After integration I opened my application & logged in different times in the same browser tab. I am able to see the custom dimension in piwik dashboard but it is always updating the same row to different values rather than creating a new row for each login & logout.

I am calling setCustomDimension once user lands into home page.

Also I am seeing another issue but I dont know the exact reason, When ever user navigates to home page after logging in instantly I was able to see the visitor log in my piwik dashboard but It is taking longer time ( nearly 10 minutes) to see the updated custom dimension. Is there any thing that I am missing (since I am seeing a big lag in dashboard actions tab where as everything is fast in dashboard tab).

Rama Krishna.