The collection that it references has about 2000 docs only.

We've seen this multiple times on 1.6.5, and we upgraded to 1.7.5 today and we still see it happening, this time happened 2 hours after the upgrade, after they happen they go for a long time until I step down the master

Here is part of the log with the error and the trace.

Thu Feb 10 20:02:36 [conn960] query ee895ca8156f4c7fa4104b1b4c9a8c38.$cmd ntoreturn:1 command: { group: { ns: "LEADEBOARD_cityofwonder-g-300_l", key:

{ value: true }

, cond: null, $reduce: "functi
on(doc,prev)

{ prev.numEntries ++ }", initial: { numEntries: 0 } } } reslen:28106 89617ms
Thu Feb 10 20:02:36 [conn809] query ee895ca8156f4c7fa4104b1b4c9a8c38.$cmd ntoreturn:1 command: { group: { ns: "LEADEBOARD_cityofwonder-g-300_l", key: { value: true }, cond: null, $reduce: "functi
on(doc,prev) { prev.numEntries ++ }

", initial:

{ numEntries: 0 }

} } reslen:28106 95479msThu Feb 10 20:02:36 [initandlisten] connection accepted from 10.36.115.8:41194 #3640
Thu Feb 10 20:02:37 [initandlisten] connection accepted from 10.36.115.6:45369 #3641
Thu Feb 10 20:02:37 [initandlisten] connection accepted from 10.36.115.6:45370 #3642
Thu Feb 10 20:02:37 [initandlisten] connection accepted from 10.36.115.8:41198 #3643
Thu Feb 10 20:02:37 [initandlisten] connection accepted from 10.36.105.84:28486 #3644
Thu Feb 10 20:02:37 [initandlisten] connection accepted from 10.36.115.6:45373 #3645
Thu Feb 10 20:02:37 [conn292] query ee895ca8156f4c7fa4104b1b4c9a8c38.$cmd ntoreturn:1 command: { group: { ns: "LEADEBOARD_cityofwonder-g-300_l", key:

{ value: true }

, cond: null, $reduce: "functi
on(doc,prev)

{ prev.numEntries ++ }", initial: { numEntries: 0 } } } reslen:28106 90503ms
Thu Feb 10 20:02:37 [conn277] getmore local.oplog.rs cid:3808073055396120208 getMore: { ts: { $gte: new Date(5572222262670524418) } } bytes:20 nreturned:0 97034ms
Thu Feb 10 20:02:37 [conn2346] killcursors: found 0 of 1
Thu Feb 10 20:02:37 [conn2346] killcursors: found 0 of 1
Thu Feb 10 20:02:41 [conn2354] JS Error: out of memory
Thu Feb 10 20:02:41 [conn2174] JS Error: out of memory
Thu Feb 10 20:02:41 [conn2174] Assertion: 10432:JS_NewObject failed for global
0x560819 0x61ddc7 0x6129c3 0x605f57 0x604b59 0x7f435b 0x7f6594 0x7d55e2 0x7d64e1 0x63fdc5 0x645e85 0x74dc0c 0x75399d 0x89a15e 0x8ad550 0x7f28d5e419ca 0x7f28d53f070d
/usr/bin/mongod(_ZN5mongo11msgassertedEiPKc+0x129) [0x560819]
/usr/bin/mongod(_ZN5mongo7SMScopeC1Ev+0x247) [0x61ddc7]
/usr/bin/mongod(_ZN5mongo8SMEngine11createScopeEv+0x23) [0x6129c3]
/usr/bin/mongod(_ZN5mongo12ScriptEngine8newScopeEv+0x17) [0x605f57]
/usr/bin/mongod(_ZN5mongo12ScriptEngine14getPooledScopeERKSs+0x259) [0x604b59]
/usr/bin/mongod(_ZN5mongo12GroupCommand5groupESsRKSsRKNS_7BSONObjES3_SsSsPKcS3_SsRSsRNS_14BSONObjBuilderE+0x4b) [0x7f435b]
/usr/bin/mongod(_ZN5mongo12GroupCommand3runERKSsRNS_7BSONObjERSsRNS_14BSONObjBuilderEb+0xe34) [0x7f6594]
/usr/bin/mongod(_ZN5mongo11execCommandEPNS_7CommandERNS_6ClientEiPKcRNS_7BSONObjERNS_14BSONObjBuilderEb+0x9e2) [0x7d55e2]
/usr/bin/mongod(_ZN5mongo12_runCommandsEPKcRNS_7BSONObjERNS_10BufBuilderERNS_14BSONObjBuilderEbi+0x851) [0x7d64e1]
/usr/bin/mongod(_ZN5mongo11runCommandsEPKcRNS_7BSONObjERNS_5CurOpERNS_10BufBuilderERNS_14BSONObjBuilderEbi+0x35) [0x63fdc5]
/usr/bin/mongod(ZN5mongo8runQueryERNS_7MessageERNS_12QueryMessageERNS_5CurOpES1+0x3005) [0x645e85]
/usr/bin/mongod() [0x74dc0c]
/usr/bin/mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_8SockAddrE+0x5ad) [0x75399d]
/usr/bin/mongod(_ZN5mongo10connThreadEPNS_13MessagingPortE+0x21e) [0x89a15e]
/usr/bin/mongod(thread_proxy+0x80) [0x8ad550]
/lib/libpthread.so.0(+0x69ca) [0x7f28d5e419ca]
/lib/libc.so.6(clone+0x6d) [0x7f28d53f070d]
Thu Feb 10 20:02:41 [conn2174] query ee895ca8156f4c7fa4104b1b4c9a8c38.$cmd ntoreturn:1 command: { group: { ns: "LEADEBOARD_cityofwonder-18-1-300_l", key: { value: true }, cond: null, $reduce: "function(doc,prev) { prev.numEntries ++ }

", initial:

{ numEntries: 0 }

} } reslen:117 52518ms
Thu Feb 10 20:02:41 [conn1563] JS Error: out of memory
Thu Feb 10 20:02:41 [conn1563] Assertion: 10432:JS_NewObject failed for global
0x560819 0x61ddc7 0x6129c3 0x605f57 0x604b59 0x7f435b 0x7f6594 0x7d55e2 0x7d64e1 0x63fdc5 0x645e85 0x74dc0c 0x75399d 0x89a15e 0x8ad550 0x7f28d5e419ca 0x7f28d53f070d
/usr/bin/mongod(_ZN5mongo11msgassertedEiPKc+0x129) [0x560819]
/usr/bin/mongod(_ZN5mongo7SMScopeC1Ev+0x247) [0x61ddc7]
/usr/bin/mongod(_ZN5mongo8SMEngine11createScopeEv+0x23) [0x6129c3]
/usr/bin/mongod(_ZN5mongo12ScriptEngine8newScopeEv+0x17) [0x605f57]
/usr/bin/mongod(_ZN5mongo12ScriptEngine14getPooledScopeERKSs+0x259) [0x604b59]
/usr/bin/mongod(_ZN5mongo12GroupCommand5groupESsRKSsRKNS_7BSONObjES3_SsSsPKcS3_SsRSsRNS_14BSONObjBuilderE+0x4b) [0x7f435b]
/usr/bin/mongod(_ZN5mongo12GroupCommand3runERKSsRNS_7BSONObjERSsRNS_14BSONObjBuilderEb+0xe34) [0x7f6594]
/usr/bin/mongod(_ZN5mongo11execCommandEPNS_7CommandERNS_6ClientEiPKcRNS_7BSONObjERNS_14BSONObjBuilderEb+0x9e2) [0x7d55e2]
/usr/bin/mongod(_ZN5mongo12_runCommandsEPKcRNS_7BSONObjERNS_10BufBuilderERNS_14BSONObjBuilderEbi+0x851) [0x7d64e1]
/usr/bin/mongod(_ZN5mongo11runCommandsEPKcRNS_7BSONObjERNS_5CurOpERNS_10BufBuilderERNS_14BSONObjBuilderEbi+0x35) [0x63fdc5]