[unboggling]

Speeding Up:

1. In external security software, disable virus scanning of official calibre Library folders.

2. Hide the Tag Browser in calibre when not using it directly, particularly before quitting calibre so it won't be open the next time calibre starts up.

3. Disable unnecessary plugins where calibre allows, such as Device Interface plugins for devices you don't use, and any installed but currently unused third-party plugins such as for Metadata Source and User Interface. All enabled plugins take time to initialize at calibre startup. You can enable rarely-used plugins specifically only when you need them.

4. Use as few columns "built from other columns" as possible.

5. Avoid using complex template language or programming particularly where it has to iterate through large numbers of books in the library or restriction, one instance of which occurs at calibre startup.

6. Prefix all searches with the column lookup name, including in saved searches and restrictions. Unprefixed searches in a large library can be time consuming even with Prefs/Searching/"Limit the searched metadata" set to exclude Comments and to include the most useful and simple columns. Also where possible, do intensive search operations within pre-set restrictions ( -- restrictions limit the number of books to be searched through to a subset of the library).

There are probably other performance issues/tips for large libraries that siipped my mind at the moment, or that I haven't learned yet.