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Old 07-06-2020, 01:16 PM   #16
droopy
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Posts: 834
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Join Date: Apr 2009
Device: Kobo Forma
Quote:
Originally Posted by DaltonST View Post
If you make a lot of metadata changes via various plugins, you will see that the metadata.db file will grow enormously due to unclaimed SQLite database space.

Real example statistics from a SQLite browsing tool that does a compress:

Before compacting<<<----------->>>After compacting:
Page Count = 118,342<<<---------->>>Page Count = 3,606
Database Size = 121,182,208 bytes<<>>Database Size = 3,692,544 bytes

So, the metadata.db file went from over 121mb to less than 4mb in size.


If you have many Libraries, and if you use Job Spy, there is a menu option under "Utilities" named "Vacuum/Compress metadata.db [All Other Libraries]". It vacuums all except the current Library which is open in Calibre at the moment. Libraries must be "closed" to be vacuumed.
Dalton's page count was reduced to 1/40th of its original size and db size reduced to 1/33th. How does this affect Calibre performance?

What are the side effects of never vacuuming?


Kovid, do you think "vacuuming" should be automatically done by Calibre?
I ask for 2 reasons:
1. I don't want any changes to modification date
2. If it's beneficial, it's good for it to be automatic

Last edited by droopy; 07-06-2020 at 01:28 PM.
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