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We did, but for basically anything over 1GB we found heap dumps to be prohibitively slow. Then, instead of failing for one request we'd basically end up killin
by rwalker 15y ago
We did, but for basically anything over 1GB we found heap dumps to be prohibitively slow. Then, instead of failing for one request we'd basically end up killing the whole server.
- justinsb 15y agoDefinitely hear you on that one! It only really works if you can put up with a service going down for a while (e.g. not customer facing, or one back-end in a web cluster with a load balancer in front). I can see how that wouldn't work for Greplin. Looks very useful now that I better understand the context.
- SpikeGronim 15y agoI've had good experience with 2GB heap dumps. Actually dumping it was, in my experience, pretty quick. It was essentially as fast as the machine could do that much sequential IO. You get a lot more detail, like what was in those Strings that took up the whole heap. That is usually invaluable for diagnosing what's really wrong. Actually analyzing a multi-GB heap dump takes 2-3x as much heap for the analyzer. The jhat tool that ships with the JVM is perfectly capable of analyzing a 2 GB heap if it has 6 GB of its own heap to play with.