(note: this page originally created following greggles’ request at http://drupal.org/node/1369894#comment–5397968)
Data Collection modules are those that track data values which change over time. Note that this does not include analytics modules, which display a very specific type of data, and most commonly for administrator roles, but for modules that track data which is to be presented as part of the content of the site. This might include external service data such as stock ticker values, sensor readings or counts of specific sorts of user interactions.
Following is a list of modules that provide functionality related to the collection of values over time.
Data Collection Module Comparison
RRDTool
Drupal 6 and 7, dev only as of this writing.
“A collection of modules providing apis for integrating drupal with RRDtool, the round-robin database tool, used for tracking time-series data.”
The RRD system is especially well known for large and/or frequently updated data sets, and is used in a wide range of enterprise and industrial applications. Highly technical.
Sampler
Drupal 6 only, as of this writing.
“The Sampler API allows modules to easily collect and store calculated pieces of data.”
Sampler uses a polling approach to periodically record the value of a scalar data source and stores each recorded value in the database. It offers a robust API along with a flexible architecture to define alternate storage methods, sampling strategies, etc. Also includes Drush plugin.
Counter API
Drupal 6 only, as of this writing. Sandbox project with currently pending application for full project status.
“The Counter API module provides a generic infrastructure for the creation of event counters that can be incremented, managed and displayed as needed by other modules. Use cases for this module include ‘action’ counters which can display the number of users who have participated in a given site action and donation progress bars that show ‘amount to goal’.”
Stats
Drupal 6 only, as of this writing.
“Stats provides an API for creation, calculation and storage of statistic values.”
Intended primarily for sports statistics, supports presentation of aggregation operations over data sets, integrates with the Results module for presentation of data.
Analytics modules
The following modules deal with “statistics”, but are primarily analytics modules geared toward the tracking and presentation of specific data types related to site analytics:
- Counter: “Counter module counts how many visitors on your website!”
- Field Statistics Field: Currently empty, but judging by the name appears to be a field-level module for display of statistics. Likely site statistics.