The previous admin commands focus on various aspects of user management and behavior. The following admin commands focus on the server software itself. The Server Stats command prints out a variety of information related to the current and recent usage of the server.
Figure 9.10, “ The ServerStats command ” illustrates an invocation of this command.
The output from the Server Stats command is organized into sections.
The first section, Build and Version information, lists version information about the current server, as well as how long it has been running.
The second section, Data File Information, provides statistics on the total number of data files stored on this server, their total size, and the total number of users with data files, as well as a breakdown of this information for just the previous day.
The third section lists the emails of those users who sent sensor data to this server during the previous day.
The fourth section lists the current state of the heap. Note that the Server Stats command has a "GC first" parameter. If this parameter is set to "Yes" before invoking the command, then the Java garbage collector is requested to run before these statistics are collected. Note that the Java garbage collector has a mind of its own, and there is no guarantee that requesting a GC will actually lead to a GC. We have found that in many cases, it does.
The fifth section lists the number of entries in the various caches in the system. This section, along with the last section, "SensorData RecentlyModified Set", provides data of interest primarily to Hackystat developers.