3 Replies Latest reply on Sep 4, 2019 6:37 AM by Gorkem Sevinc

    Hanging on to DB connections in Tableau online with MySQL

    Gorkem Sevinc

      Hi all,

       

      Hoping for some help / insight into a problem I'm facing now. We are using Tableau Online with MySQL 5.5.54 (read copy of an AWS RDS instance) and run some views (about 15) as subscriptions with near-real-time data, so using a live connection. When I run the subscriptions, I noticed that it's hanging on to the db connections and not terminating them once the report has been run. Am I missing something obvious here? Are there any logs that I can find or configuration on db termination rules Tableau should follow on live connections?

       

      Obviously I'll try the extract method separately, but this seems like a major bug to me if this is factual.

       

      Thank you

      Gorkem

        • 1. Re: Hanging on to DB connections in Tableau online with MySQL
          Michael Gillespie

          Well, it's a live connection, so there could be a request at any time.  While I don't know the internals and what the timeout might be for a live vs. extract data source, it doesn't sound that surprising that a frequently accessed near-real-time data source would have a persistent connection.

          • 2. Re: Hanging on to DB connections in Tableau online with MySQL
            Ken Flerlage

            What's the reason for the concern over these connections? Most database platforms leverage connection pooling which keeps connections alive so they can be reused by other threads. Could that be what's happening here? Ultimately, I don't think this unclosed connection is anything to worry about.

            • 3. Re: Hanging on to DB connections in Tableau online with MySQL
              Gorkem Sevinc

              Thanks Ken and Michael for your responses. Let me explain a bit further - I have a dashboard that ends up having 11 connections to the same db (don't get me started on why, bad data architecture / separate DBs, going away soon) and am creating views such that I have 10 filtered views being sent via email subscriptions. As I run these subscriptions, each creates 10 separate connections, creating about 110 connections as they run. Persisting these connections would be fine if each view reused the original 11 connections; but each view is creating its own 11 and exhausting the connection pool.

               

              I see that the timeout for a live connection is about 20 mins with MySQL, so I can probably architect around it. My surprise is mostly regarding different views of the same dashboard not reusing existing connections.