Apologies for butting in on this thread, but I saw the following response from Tim recently and it made me wonder ...
On Tue, 26 May 2015 14:13:05 +0100 Tim Bunce <tim.bu...@pobox.com> wrote: > I've added this as a note: > > Note that the ChildHandles array holds weak references and that 'from > time to time' the old slots get freed up. This isn't a leak, it just > appears to be if you're not familiar with the caching that DBI does > internally. You can rest assured that if the DBI did have a real leak > a) a great many people would be affected and b) it would get fixed very > quickly. > > I think 'from time to time' is every 120 or so newly created child handles. A while ago we had a mysterious problem using DBI in an application that was written as a plugin for the foswiki platform. Since our foswiki instance was running persistently under fcgid it was long-running and over time we'd see a gradual increase in the open connections it held to our mysql database server. Eventually our server would reach it's maximum connection count and reject new connections. The most recent time I tried to debug this was over a year ago (March 2014) and there was a brief exchange of emails on this list with the subject "DBI Mysql Driver Handle Mysteriously Changes". Since then we've given up (!) and changed the way our application ran so it is no longer a foswiki plugin. That seems to have "fixed" the connection leakage and so we are unlikely to ever go back to find out exactly what was going on here. But seeing this response from Tim about the fact that the DBI can cache up to 120 or so handles made me wonder if this is true for database handles as well as statement handles? Is it possible that our "problem" was simply the correctly working DBI caching misbehaving due to our application running persistently in multiple fcgid processes. I'm not looking to re-open investigating this issue - our environement has now changed sufficiently that recreating the set up with the connection leak to do more debugging would be quite difficult. But I was just curious about whether the above could be the case. If the answer is "no" I'll be happy to just leave it at that! Thanks. Duncan
