Saturday, March 3, 2012

Runtime Statistics in CouchDB


CouchDB  is an open source document-oriented database. More information on CouchDB is available here

CouchDB 0.9 and above comes with a list of counters that lets you inspect how CouchDB performs. On windows (local machine where CouchDB is installed), you can view these counters by navigating to the following URL: http://localhost:5984/_stats. More information is available here.

The information returned is in JSON format. There are free tools and websites available to display the stats in a more user friendly format.


GroupKeyDescription
Couchdbdatabase_writesNumber  of times a database was changed
open_databasesNumber  of open databases
auth_cache_hitsNumber  of authentication cache hits
auth_cache_missesNumber  of authentication cache misses
database_readsNumber  of times a document was read from a database
request_timeLength of a request inside CouchDB without MochiWeb
open_os_filesNumber  of file descriptors CouchDB has open
httpdRequestsNumber  of HTTP requests
bulk_requestsNumber  of bulk requests
view_readsNumber  of view reads
clients_requesting_changesNumber  of clients for continuous _changes
temporary_view_readsNumber  of temporary view reads
httpd_request_methodsDELETENumber  of HTTP DELETE requests
HEADNumber  of HTTP HEAD requests
POSTNumber  of HTTP POST requests
PUTNumber  of HTTP PUT requests
GETNumber  of HTTP GET requests
COPYNumber  of HTTP COPY requests
httpd_status_codes400Number  of HTTP 400 Bad Request responses
201Number  of HTTP 201 Created responses
403Number  of HTTP 403 Forbidden responses
409Number  of HTTP 409 Conflict responses
200Number  of HTTP 200 OK responses
202Number  of HTTP 202 Accepted responses
404Number  of HTTP 404 Not Found responses
301Number  of HTTP 301 Moved Permanently responses
405Number  of HTTP 405 Method Not Allowed responses
500Number  of HTTP 500 Internal Server Error responses
401Number  of HTTP 401 Unauthorized responses
304Number  of HTTP 304 Not Modified responses
412Number  of HTTP 412 Precondition Failed responses

Below is a formated JSON output example:

{ "couchdb" : { "auth_cache_hits" : { "current" : 2089.0,
          "description" : "number of authentication cache hits",
          "max" : 222,
          "mean" : 0.83199999999999996,
          "min" : 0,
          "stddev" : 10.222,
          "sum" : 2089.0
        },
      "auth_cache_misses" : { "current" : 12.0,
          "description" : "number of authentication cache misses",
          "max" : 3,
          "mean" : 0.0050000000000000001,
          "min" : 0,
          "stddev" : 0.113,
          "sum" : 12.0
        },
      "database_reads" : { "current" : 643.0,
          "description" : "number of times a document was read from a database",
          "max" : 131,
          "mean" : 0.25700000000000001,
          "min" : 0,
          "stddev" : 4.1050000000000004,
          "sum" : 643.0
        },
      "database_writes" : { "current" : 205.0,
          "description" : "number of times a database was changed",
          "max" : 28,
          "mean" : 0.082000000000000003,
          "min" : 0,
          "stddev" : 1.056,
          "sum" : 205.0
        },
      "open_databases" : { "current" : 10.0,
          "description" : "number of open databases",
          "max" : 7,
          "mean" : 0.0040000000000000001,
          "min" : -5,
          "stddev" : 0.21099999999999999,
          "sum" : 10.0
        },
      "open_os_files" : { "current" : 10.0,
          "description" : "number of file descriptors CouchDB has open",
          "max" : 7,
          "mean" : 0.0040000000000000001,
          "min" : -5,
          "stddev" : 0.28699999999999998,
          "sum" : 10.0
        },
      "request_time" : { "current" : 13881.477999999999,
          "description" : "length of a request inside CouchDB without MochiWeb",
          "max" : 12043.0,
          "mean" : 115.679,
          "min" : 0.0,
          "stddev" : 1098.511,
          "sum" : 13881.477999999999
        }
    },
  "httpd" : { "bulk_requests" : { "current" : 27.0,
          "description" : "number of bulk requests",
          "max" : 10,
          "mean" : 0.010999999999999999,
          "min" : 0,
          "stddev" : 0.253,
          "sum" : 27.0
        },
      "clients_requesting_changes" : { "current" : null,
          "description" : "number of clients for continuous _changes",
          "max" : null,
          "mean" : null,
          "min" : null,
          "stddev" : null,
          "sum" : null
        },
      "requests" : { "current" : 2395.0,
          "description" : "number of HTTP requests",
          "max" : 221,
          "mean" : 0.95299999999999996,
          "min" : 0,
          "stddev" : 10.359999999999999,
          "sum" : 2395.0
        },
      "temporary_view_reads" : { "current" : 92.0,
          "description" : "number of temporary view reads",
          "max" : 33,
          "mean" : 0.036999999999999998,
          "min" : 0,
          "stddev" : 0.94199999999999995,
          "sum" : 92.0
        },
      "view_reads" : { "current" : 144.0,
          "description" : "number of view reads",
          "max" : 37,
          "mean" : 0.058000000000000003,
          "min" : 0,
          "stddev" : 1.1579999999999999,
          "sum" : 144.0
        }
    },
  "httpd_request_methods" : { "COPY" : { "current" : 1.0,
          "description" : "number of HTTP COPY requests",
          "max" : 1,
          "mean" : 0.0,
          "min" : 0,
          "stddev" : 0.02,
          "sum" : 1.0
        },
      "DELETE" : { "current" : 187.0,
          "description" : "number of HTTP DELETE requests",
          "max" : 81,
          "mean" : 0.074999999999999997,
          "min" : 0,
          "stddev" : 1.6919999999999999,
          "sum" : 187.0
        },
      "GET" : { "current" : 1672.0,
          "description" : "number of HTTP GET requests",
          "max" : 222,
          "mean" : 0.66600000000000004,
          "min" : 0,
          "stddev" : 9.1310000000000002,
          "sum" : 1672.0
        },
      "HEAD" : { "current" : null,
          "description" : "number of HTTP HEAD requests",
          "max" : null,
          "mean" : null,
          "min" : null,
          "stddev" : null,
          "sum" : null
        },
      "POST" : { "current" : 190.0,
          "description" : "number of HTTP POST requests",
          "max" : 35,
          "mean" : 0.075999999999999998,
          "min" : 0,
          "stddev" : 1.1719999999999999,
          "sum" : 190.0
        },
      "PUT" : { "current" : 345.0,
          "description" : "number of HTTP PUT requests",
          "max" : 85,
          "mean" : 0.13700000000000001,
          "min" : 0,
          "stddev" : 2.1110000000000002,
          "sum" : 345.0
        }
    },
  "httpd_status_codes" : { "200" : { "current" : 1734.0,
          "description" : "number of HTTP 200 OK responses",
          "max" : 221,
          "mean" : 0.68999999999999995,
          "min" : 0,
          "stddev" : 9.2690000000000001,
          "sum" : 1734.0
        },
      "201" : { "current" : 245.0,
          "description" : "number of HTTP 201 Created responses",
          "max" : 31,
          "mean" : 0.098000000000000004,
          "min" : 0,
          "stddev" : 1.2170000000000001,
          "sum" : 245.0
        },
      "202" : { "current" : 3.0,
          "description" : "number of HTTP 202 Accepted responses",
          "max" : 1,
          "mean" : 0.001,
          "min" : 0,
          "stddev" : 0.035000000000000003,
          "sum" : 3.0
        },
      "301" : { "current" : 3.0,
          "description" : "number of HTTP 301 Moved Permanently responses",
          "max" : 1,
          "mean" : 0.001,
          "min" : 0,
          "stddev" : 0.035000000000000003,
          "sum" : 3.0
        },
      "304" : { "current" : 25.0,
          "description" : "number of HTTP 304 Not Modified responses",
          "max" : 8,
          "mean" : 0.01,
          "min" : 0,
          "stddev" : 0.215,
          "sum" : 25.0
        },
      "400" : { "current" : 23.0,
          "description" : "number of HTTP 400 Bad Request responses",
          "max" : 8,
          "mean" : 0.0089999999999999993,
          "min" : 0,
          "stddev" : 0.22900000000000001,
          "sum" : 23.0
        },
      "401" : { "current" : 5.0,
          "description" : "number of HTTP 401 Unauthorized responses",
          "max" : 2,
          "mean" : 0.002,
          "min" : 0,
          "stddev" : 0.059999999999999998,
          "sum" : 5.0
        },
      "403" : { "current" : 14.0,
          "description" : "number of HTTP 403 Forbidden responses",
          "max" : 6,
          "mean" : 0.0060000000000000001,
          "min" : 0,
          "stddev" : 0.156,
          "sum" : 14.0
        },
      "404" : { "current" : 100.0,
          "description" : "number of HTTP 404 Not Found responses",
          "max" : 80,
          "mean" : 0.040000000000000001,
          "min" : 0,
          "stddev" : 1.6220000000000001,
          "sum" : 100.0
        },
      "405" : { "current" : 3.0,
          "description" : "number of HTTP 405 Method Not Allowed responses",
          "max" : 1,
          "mean" : 0.001,
          "min" : 0,
          "stddev" : 0.035000000000000003,
          "sum" : 3.0
        },
      "409" : { "current" : 3.0,
          "description" : "number of HTTP 409 Conflict responses",
          "max" : 1,
          "mean" : 0.001,
          "min" : 0,
          "stddev" : 0.035000000000000003,
          "sum" : 3.0
        },
      "412" : { "current" : null,
          "description" : "number of HTTP 412 Precondition Failed responses",
          "max" : null,
          "mean" : null,
          "min" : null,
          "stddev" : null,
          "sum" : null
        },
      "500" : { "current" : 87.0,
          "description" : "number of HTTP 500 Internal Server Error responses",
          "max" : 75,
          "mean" : 0.035000000000000003,
          "min" : 0,
          "stddev" : 1.508,
          "sum" : 87.0
        }
    }
} 

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