Why does fp-info-cache get large even when nothing in it is needed?

I know what fp-info-cache is for but I noticed that a couple of projects had an fp-info-cache of 2.7 MB or so, even though nothing from it was needed, verified by deleting the cache, reopening the PCB, then closing.

The disk space isn’t a biggie. I’m just curious what operation I did caused it to cache so much. It varies from project to project, only a handful have a cache this large.

The cache is created to speed up any interaction with the footprint library. I think in future it might get moved to a central location as the cache is not really project specific but installation specific (assuming you mostly use global libs)

That’s the right point. I work for different companies and I don’t like this cache in my projects. It mixes up the information of a company with that of another. It doesn’t hurt the project itself but it should not be placed in the project directory.

I don’t understand this point: if we moved to a global fp-info-cache, that cache would include all the info from all libraries you ever open on that PC, which seems like it mixes together information a lot more than the current system. With the current system, if you want to keep separate libraries for projects, at least you can do that and the library cache info is stored within each project directory.

By the way, this cache gets filled if you have footprint previews turned on in the symbol chooser, so that might be one way the file can grow without you opening a PCB.

Hi Jon,

It seems so now. I have a fp-info-cache file in a project folder with 24088 lines.
It contains information of many projects. A lot of company-specific libraries information.

Why this cache keeps information of many projects is a mystery for me.

It should be a combination of any project-specific libraries and your global libraries. If you put your company-specific libraries in your global library table, they will be included in the cache.

Thanks for your answer. Now it is not a mystery anymore!

As it is not possible to have two or more global library tables, I will keep on deleting the fp-info-cache when sending or archiving a project.

You can delete those?! I thought it may be needed for creating an archive.

Is the cache.lib used when archiving a project?
Is there an explanation of what happens when creating an archive? I see that archiving creates a new project specific library, “project.lib”.
Does it then set any of the paths to the newly created project library?
I have not tried unarchiving a project on a different machine.

cheers,
-Bryan

fp-info-cache is completely different than *-cache.lib. The former is a cache in more restricted technical sense – basically for more efficient functioning but not needed. But cache.lib is different and must never be touched or removed.

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More details: What are the cache and rescue libs and how does the schematic rescue dialog work? (KiCad version 5.x and earlier)

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