Mongodb - wiredtiger memory usage
We switched to wiredtiger and saw the memory usage creeping up and mongodb using 90% of the memory on the system. He seems to be moving slowly. Before wiredtiger, when we used mmap on mongo, 2.x memory would sit at 8%.
I'm worried about the operating system killing the process. Is this normal behavior?
db.serverStatus () - https://gist.github.com/henryoswald/8ff9cf917e63c2e983dd
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There is a big difference between mmap and WiredTiger in the way they use memory.
Whereas mmap actually uses memory mapping, so the database cache is actually counted as a cache in the OS.
Whereas WiredTiger uses the memory pool defined when the application starts. view documents
Depending on the amount of memory on your system, by default it should use 1GB or half of the RAM for the WiredTiger pool. (which explains the jump from 8% to 58% or so)
But it shouldn't be "slowly creeping up to 90%". This deserves further study. But for this we need more information. As well as db.serverStatus()
, or the method used to find memory, or whatever you can find and share about this server instance.
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