CouchDB crashes after few minutes running - crash

Question

CouchDB is very unpleasant for me. Niether documentation, nor tips could help me at all. The situation is like that:
FreeBSD 9.2 amd64
couchdb-1.5.0,2 installed from ports
npm couchapp
npm semver.
Started replication in CouchDB for node repo and amazing crashes are happening every several minutes. I wrote a script which tests process every 5 seconds:
13:40:53
13:48:11 7m42s [growing tendention]
13:56:09 7m58s
14:04:11 8m02s
14:12:23 8m12s
14:21:14 8m12s
14:30:08 8m54s
14:40:48 10m40s
14:57:13 16m35s [stop growing tendention]
15:08:29 11m16s
...
couch.log: (not always, sometimes nothing at all)
Tue, 06 May 2014 12:59:51 GMT] [error] [<0.134.0>] Error in replication `[REPLICATION_HASH]+continuous` (triggered by document `npmjs_repl`): timeout
Restarting replication in 40 seconds.
[info] [<0.372.0>] Replication `"[REPLICATION_HASH]+continuous"` is using:
4 worker processes
a worker batch size of 500
20 HTTP connections
a connection timeout of 30000 milliseconds
10 retries per request
socket options are: [{keepalive,true},{nodelay,false}]
source start sequence 203628
[Tue, 06 May 2014 13:00:32 GMT] [info] [<0.372.0>] Replication `"[REPLICATION_HASH]7+continuous"` is using:
4 worker processes
a worker batch size of 500
20 HTTP connections
a connection timeout of 30000 milliseconds
10 retries per request
socket options are: [{keepalive,true},{nodelay,false}]
source start sequence 203628
err.log (in every crash)
heart: Tue May 6 15:06:14 2014: heart-beat time-out, no activity for 13 seconds
heart: Tue May 6 15:06:16 2014: Executed "/usr/local/bin/couchdb -k" -> 0. Terminating.
heart_beat_kill_pid = 52979
heart_beat_timeout = 11
truss output:
...
kevent(3,0x0,0,{},256,{0.000000000 }) = 0 (0x0)
kevent(3,0x0,0,{},256,{0.000000000 }) = 0 (0x0)
kevent(3,0x0,0,{},256,{0.000000000 }) = 0 (0x0)
kevent(3,0x0,0,{},256,{0.000000000 }) = 0 (0x0)
kevent(3,0x0,0,{},256,{0.000000000 }) = 0 (0x0)
mmap(0x0,4194304,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANON,-1,0x0) = 17431527424 (0x40f000000)
SIGNAL 9 (SIGKILL)
process exit, rval = 0
Thanks for helping.