search

jankotek / mapdb

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.
https://mapdb.org
Apache License 2.0
4.91k stars 875 forks source link

How to know the off-heap memory usage #710

Open z7658329 opened 8 years ago

z7658329 commented 8 years ago

How to know the off-heap memory usage ?is there any api that mapdb offers? here is my JVM start parameters: java -server -Xms4096m -Xmx4096m -XX:MaxDirectMemorySize=4G -XX:MaxTenuringThreshold=15 -XX:+PrintGCDateStamps -XX:+PrintGCDetails -Xloggc:./gc.log -jar ./offheap-benchmark.jar

jankotek commented 8 years ago

There is a way, I will update doc and add an example

z7658329 commented 8 years ago

ok！thanks very much,now i have tested for two days,mapdb is more effective than other off-heap frameworks,about 20W/S read and write~so our company prepare to use mapdb,how long can i see the last doc and example?now we eager to see the usage of memory

jankotek commented 8 years ago

About two weeks

z7658329 commented 8 years ago

could you tell me first,thanks! i really eager to know right now,can you send the way to my email? here is my email:hejiacong@gmail.com

bwzhang2011 commented 8 years ago

@z7658329, would you mind sharing your test cases to verify that the latest mapdb reached that speed ?

minborg commented 8 years ago

Check out the jvisualvm plugin "VisualVM-Buffer Monitor". Using this tool, you can see exactly how much mapdb is allocating off heap.

KeyOfSpectator commented 8 years ago

@jankotek Hello , Would you mind sharing the way to know the off-heap memory usage ? Or maybe you have finished the doc, I just miss it