Reading/Multimedia/Metrics

This page aims to contain a comprehensive list of metrics and graphs for Media Viewer, both from a usage and technical perspective. It explains in layman terms what the technical graphs mean. This page should be the central place to watch the impact of a Media Viewer launch or major change.

= Activity =

http://multimedia-metrics.wmflabs.org/dashboards/mmv

Global and local total action counts.


 * thumbnail-link-click how many times users clicked on a thumbnail which opened media viewer
 * enlarge-link-click how many times users clicked on the "enlarge" icon next to the thumbnail which opened media viewer
 * fullscreen-link-click how many times users went into fullscreen mode
 * defullscreen-link-click how many times users exited fullscreen mode
 * site-link-click how many times users clicked on the link to the site where the File: page of that image is hosted
 * close-link-click how many times users clicked on the close button or pressed escape to close media viewer
 * use-this-file-link-click how many times users clicked on "use this file"
 * image-view how many times users viewed an image

= Performance =

http://multimedia-metrics.wmflabs.org/dashboards/mmv#performance-graphs-tab

These are technical performance metrics, collection how long things take on the client side by sampling users. By default the limn graphs have all metrics turned on, which doesn't give a clear view. It's best to disable most metrics except the ones you want to investigate.

What the prefixes mean:
 * userinfo API call fetching information about users. Mainly used for correct gender-based localization of text
 * imageinfo API call fetching general information about the image
 * thumbnailinfo API call fetching information about a thumbnail of a specific size for the image
 * filerepoinfo
 * imageusage
 * globalusage
 * image the images shown in Media Viewer. This metric doesn't differentiate Varnish cache hits and misses
 * imagemiss the images shown in Media Viewer that needed to be generated on the fly (cache miss)
 * imagehit the images shown in Media Viewer that already existed (cache hit)

What the suffixes mean:
 * mean The mathematical mean for that metric
 * std The standard deviation for that metric
 * sample_size The sample size, i.e. how many times on a given day was that metric recorded

sample_size is very important, because it lets us know how reliable the metric on a given day and graph is.

= Ops =


 * Image scalers http://ganglia.wikimedia.org/latest/?r=hour&cs=&ce=&s=by+name&c=Image%2520scalers%2520eqiad&tab=m&vn=&hide-hf=false

These servers are responsible for generating thumbnails, which Media Viewer triggers a lot since thumbnails are generated on-the-fly when they don't exist yet.


 * API methods http://gdash.wikimedia.org/dashboards/apimethods/
 * PHP latency http://gdash.wikimedia.org/dashboards/totalphp/

Media Viewer relies on several APIs on the PHP side, some of which are specific to Media Viewer.


 * StreamFile http://gdash.wikimedia.org/dashboards/filebackend/

Thumbnails, after being generated, are streamed using the StreamFile method.


 * Media Storage http://ganglia.wikimedia.org/latest/?r=hour&cs=&ce=&tab=v&vn=Media+storage&hide-hf=false

Presumably where images are stored. Not sure if originals or thumbs, we should clarify that with ops.