Tell us more. What OS are you on? On Linux, I've had good experience with inotify to watch a directory tree for changes. It doesn't detect changes made by mmap, though, so tell us also how the JSON files change. Other OSes use different notification tools.

Checking (stat)[9] would be slower than running a notification tool, but it should still be faster than reading the file every time. This method might fail to invalidate the cache properly if mmap again was used to modify the files.

Given the coordinates, do you know what JSON file holds the relevant information, or does this periodically change as well? If the latter, cache both the value and the filename. (But what would happen if there was conflicting information in two JSON files?)

What kind of information do the JSON files provide? If it's a structure that JSON can represent, you can store the decoded structure in the hash directly. 

$cache{$x}{$y}{$z} = $decoded_structure;

[download]

BTW, File::Cache is now discouraged and recommends Cache::Cache which itself is not actively developed anymore and recommends CHI instead.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: Caching files by choroba
in thread Caching files by Anonymous Monk

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