Using SQLite as a file cache

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My C++ application needs to support caching of files downloaded from the network. I started to write a native LRU implementation when someone suggested I look at using SQLite to store an ID, a file blob (typically audio files) and the the add/modify datetimes for each entry.

I have a proof of concept working well for the simple case where one client is accessing the local SQLite database file.

However, I also need to support multiple access by different processes in my application as well as support multiple instances of the application - all reading/writing to/from the same database.

I have found a bunch of posts to investigate but I wanted to ask the experts here too - is this a reasonable use case for SQLite and if so, what features/settings should I dig deeper into in order to support my multiple access case.

Thank you.

M.

sqlite
1 Answers

Most filesystems are in effect databases too, and most store two or more timestamps for each file, i.e. related to the last modification and last access time allowing implementation of an LRU cache. Using the filesystem directly will make just as efficient use of storage as any DB, and perhaps more so. The filesystem is also already geared toward efficient and relatively safe access by multiple processes (assuming you follow the rules and algorithms for safe concurrent access in a filesystem).

The main advantage of SQLite may be a slightly simpler support for sorting the list of records, though at the cost of using a separate query API. Of course a DB also offers the future ability of storing additional descriptive attributes without having to encode those in the filename or in some additional file(s).

user_8165360
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