I just noticed that several of my running bitcoind processes were using around 3+ GB of RAM, even though the mempool itself seemed to be under control.

XXXX@prime:~/bin$ ./bitcoin-cli getmempoolinfo
{
    "size" : 1896,
    "bytes" : 37341328
}

[total memory usage not shown -- I restarted bitcoind as soon as I noticed, and didn't copy it down from top]

37 MB mempool, >3 GB RAM usage. Normally, when there aren't a lot of unconfirmed txns floating around the network, memory usage is around 600 MB, so this is quite unusual.

After restarting the process and letting it run for a few minutes, I get:

  PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
[###] [XXXX]     20   0 1402M  317M 49836 S  1.0  8.2  0:41.71 ./bitcoind -daemon

XXXX@prime:~/bin$ ./bitcoin-cli getmempoolinfo
{
    "size" : 1072,
    "bytes" : 670000
}

0.67 MB mempool, 317 MB RAM usage. Much more reasonable.


Here's another node I'm running that has been online longer, before restarting:

  PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
[###] [XXXX]     20   0 4961M 3540M 11080 S  2.8 45.3  8h20:11 bin/bitcoind -daemon

XXXX@feather:~$ bin/bitcoin-cli getmempoolinfo
{
    "size" : 3045,
    "bytes" : 39656126
}

39 MB mempool, 3540 MB total memory usage. After restarting bitcoind, I see:

[XXXX]@feather:~$ bin/bitcoin-cli stop
Bitcoin server stopping
[XXXX]@feather:~$ bin/bitcoind -daemon
Bitcoin server starting
[XXXX]@feather:~$ sleep 10; bin/bitcoin-cli getmempoolinfo
{
    "size" : 39,
    "bytes" : 47037
}


  PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command
[###] [XXXX]     20   0 1640M  247M 67960 S  0.0  3.2  0:05.17 bin/bitcoind -daemon




Does anybody have any guesses where we might be leaking memory, or what is using the additional 2.4 GB? I've been using minrelaytxfee=0.00003 or similar on my nodes. Maybe there's a leak in the minrelaytxfee code path? Has anyone else seen something similar?

This issue appears to happen both with Bitcoin Core 0.10.1 and with Bitcoin XT 0.11B.