It isn't just "ONE TIME" for me. The extension freezes up often and completely stops giving autosuggestions or warnings, and the only way to fix it is to delete the .elixir_ls file and rebuild the database. When I say "often", I mean there are some days where I have to do that at least once an hour, and 5-15 minutes of high CPU usage every hour is just way too much to be acceptable.
I love Elixir and the ElixirLS extension is the best I've found so far, but that's not saying much. The extension has enough issues with it to make it very frustrating to work with, and even enough to make the entire Elixir experience not worth it in many cases.
I love Elixir, but even I have to say that the tooling story in IDEs is awful. Using VSCode, ElixirLS is the best extension I've found so far, but even the experience with it makes me want to ditch Elixir entirely more often than not (and no, the number of stars on VSCode marketplace means nothing).
The extension will often just lock up, either giving you no autosuggestions/errors, or refusing to remove errors that you've already resolved, and the only way to fix it reliably is to delete the .elixir_ls/ folder and/or completely close and restart VSCode, both of which require rebuilding the entire dialyzer which is a constant battery killer on laptops. This is such a frequent issue that some days I find myself having to quit/reopen VSCode at least once an hour, and despite spending absurd amounts of time trying to find a long term fix, I've never found one.
Not to mention the issue that has been open for 8+ months where ElixirLS is built using an older version of Elixir, and if you are using a recent version of Elixir for your project (anything newer than 1.9), some of the core functionality of ElixirLS just breaks (autocomplete and hover tips). That issue alone makes me want to ditch ElixirLS (and likely Elixir) entirely.
I love Elixir and the ElixirLS extension is the best I've found so far, but that's not saying much. The extension has enough issues with it to make it very frustrating to work with, and even enough to make the entire Elixir experience not worth it in many cases.