Here's an update:
On Nov 26, 2003, at 1:13 AM, Aparajita Fishman wrote:
I believe suspicion is falling away from that particular report; it still runs in a few seconds, but when the database freezes up, it freezes up for a long time [fifteen seconds to a minute or two].
The freeze only happens when running that report? Does the freeze occur when running the report from a 4D method?
Well ... we can see when it's happening [4D Client takes a Zen moment, 4D Server displays the Spinning Pinwheel of Doom, and the other people in the office start throwing rotten fruit at us], but we can't tell what 4D Server is doing when it's happening.
Since 4D Server's user interface is frozen when the problem occurs, we can't use any of its diagnostic tools. We have also discovered that, when 4D Server's user interface is functional, its processor utilization meters are entirely inaccurate ... according to top, Process Viewer, and CPU Monitor, running a particular overnight routine gives nearly the entire CPU to 4D Server, while 4D Server says it's only using around 6%. In addition, any processing time spent serving Active4D requests also does not show up.
We have a number of reports and other Active4D pages that do some heavy querying, but we haven't been able to hang the server just by running them. Our initial suspicions were built around the facts we observed on a freshly-started server, none of which seem to hold up:
- Connected 4D Clients don't use any CPU when they're not doing anything [this was measured with 4D Server; other tools report regular usage spikes, even with no activity]
- Usage due to Active4D pages doesn't show up [but it's not the only thing that's not reported]
- Running this database-intensive report maxed out CPU usage on 4D Server for approximately the same amount of time that it was freezing up for [because the cache wasn't warmed up; once it was, it would complete in seconds]
It's very easy to point fingers; I apologize for doing just that. When my coworker came to my desk and informed me that Active4D [and, specifically, my report] was hanging the database, my initial reaction was to turn around and ask the list for any pointers. I believe that both Active4D and my report are off the hook for now, but I don't believe the issue has been resolved yet. Either way, I'll keep you posted.
And, for the love of Pete, Aparajita, enjoy your sabbatical. You deserve it.
- D
