https://github.com/bwaldvogel/mongocachestat

Tool to collect block cache statistics for a MongoDB instance based on $showDiskLoc and mincore(2)
https://github.com/bwaldvogel/mongocachestat

Last synced: 20 days ago
JSON representation

Tool to collect block cache statistics for a MongoDB instance based on $showDiskLoc and mincore(2)

• Host: GitHub
• URL: https://github.com/bwaldvogel/mongocachestat
• Owner: bwaldvogel
• Created: 2012-10-05T20:41:27.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2014-09-26T17:18:13.000Z (about 10 years ago)
• Last Synced: 2024-10-20T06:27:43.610Z (about 1 month ago)
• Language: C++
• Homepage:
• Size: 233 KB
• Stars: 1
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
mongocachestat

==============

[![Build Status](https://travis-ci.org/bwaldvogel/mongocachestat.png?branch=master)](https://travis-ci.org/bwaldvogel/mongocachestat)

Tool to collect block cache statistics for a MongoDB instance based on

[`$showDiskLoc`][showDiskLoc] and `mincore(2)`.

Prerequisites

-------------

- MongoDB 2.6 or newer because of [SERVER-5372][SERVER-5372]

- MongoDB client library and *headers* installed

Building

--------

    # apt-get install mongodb-dev libmongo-client-dev libboost-system-dev libboost-regex-dev libboost-thread-dev libboost-filesystem-dev

    # make

Usage

-----

MongoDB needs to be up and running.

    # ./mongocachestat [--directoryPerDb]  []

Example:

    # ./mongocachestat /data/mongodb localhost:27017

Implementation detail

---------------------

Potential "Heisenberg effects" (i.e. changing the cache state by measuring with

this tool) are tried to be minimized by using `madvise(…, …, MADV_RANDOM)`.

It turns off Linux kernel read-ahead and read-behind. We call it Heisenberg

compensator in analogy to a famous science fiction series.

[showDiskLoc]: http://docs.mongodb.org/manual/reference/operator/meta/showDiskLoc/

[SERVER-5372]: https://jira.mongodb.org/browse/SERVER-5372