Databases Reference
In-Depth Information
"average_ms" : 22,
"last_ms" : 36,
"last_finished" : "Thu Jun 10 2010 15:46:54 GMT-0400 (EDT)"
},
"opcounters" : {
"insert" : 38195,
"query" : 8874,
"update" : 4058,
"delete" : 389,
"getmore" : 888,
"command" : 17731
},
"asserts" : {
"regular" : 0,
"warning" : 0,
"msg" : 0,
"user" : 5054,
"rollovers" : 0
},
"ok" : true
}
Raw status information can also be retrieved as JSON using the
MongoDB HTTP interface, at the
/_status
(
http://localhost:28017/_sta
of some other useful commands. See
“Using the Admin Inter-
face” on page 115
for more on the admin interface.
serverStatus
provides a detailed look at what is going on inside a MongoDB server.
Information such as the current server version, uptime (in seconds), and current num-
ber of connections is easily available. Some of the other information in the
serverStatus
response might need some explaining, however.
The value for
"globalLock"
gives a quick look at how much time a global write lock has
been held on the server (the times are given in microseconds).
"mem"
contains informa-
tion on how much data the server has memory mapped and what the virtual and resi-
dent memory sizes are for the server process (all in megabytes).
"indexCounters"
gives
information on the number of B-Tree lookups that have had to go to disk (
"misses"
)
versus successful lookups from memory (
"hits"
)—if this ratio starts to increase you
should consider adding more RAM, or system performance might suffer.
"background
Flushing"
tells us how many background
fsync
s have been performed and how long
they've taken. One of the most important pieces of the response is the
"opcounters"
document, which contains counters for each of the major operation types. Finally,
"asserts"
counts any assertions that have occurred on the server.
All of the counters in the
serverStatus
output are tracked from the time the server was
started and will eventually roll over if the counts get high enough. When a rollover
occurs for any counter, all counters will roll over, and the value of
"rollovers"
in the
"asserts"
document will increment.
