history: the current number of valid history files (see below).the webmap uses this to control its refresh interval. refresh: how often aircraft.json is updated (for the file version), in milliseconds.version: the version of dump1090 in use.It does not change often and you probably just want to read it once at startup. This file has general metadata about dump1090. The file versions are updated to a temporary file, then atomically renamed to the right path, so you should never see partial copies.Įach file contains a single JSON object. The file versions are written periodically for aircraft, typically once a second, for stats, once a minute. These can be exposed via a separate webserver. As a file in the directory specified by –write-json on dump1090’s command line.The json is served from the data/ path, e.g. By HTTP from dump1090’s internal webserver, which defaults to running on port 8080.There are two ways to obtain the json files: this collectd plugin feeds stats about dump1090’s operation to collectd for later graphing. These are used by the webmap, but could also be used by other things e.g. Source: MySQL :: Re: reusing ID on an AUTO_INCREMENT columnĭump1090 generates several json files with informaton about the receiver itself, currently known aircraft, and general statistics. If that’s _still_ a problem, then make the primary key a two-column key. That should handle 1000 new unique records per second, 24 hours per day, for 584 million years. If that’s a problem, then use UNSIGNED BIGINT. You can insert 1 row per second, 24 hours per day, for 136 years before you run out of values. If you use an ordinary datatype like UNSIGNED INT for your AUTO_INCREMENT column, you have 4294967295 values. It’s also a needless operation to try to make the primary key values contiguous because you’re worrid about running out. For example tax records, medical records, criminal records, etc. This can be a serious problem depending on the nature of the data. With nothing but the primary key to identify it, this creates a false reference. But the entity who now has that value is different from the one that was deleted. dependent data looking for id value ‘1234’ which is one that you deleted and then subsequently re-assigned.
It also creates a risk of false references. It’s a costly operation to find gaps so you can re-use primary key values.
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