Does the performance problem happen after opened a private window ? Do you remember setting dom.indexedDB.privateBrowsing.enabled preference to true ? Can you check what is your setting in about:preferences ? Thanks.
Bug 1829933 Comment 11 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Does the performance problem happen after opening a private window ? Do you remember setting dom.indexedDB.privateBrowsing.enabled preference to true ? Can you check what is your setting in about:preferences ? Thanks.