• Andreas Brandl's avatar
    Replace indexes for counting active users · 5b4108f0
    Andreas Brandl authored
    This adjusts the partial condition for an index. The index is intended
    to be used when counting active users with `ghost IS NOT TRUE AND
    bot_type IS NULL`.
    
    With the current index, this wasn't working as the partial condition
    didn't match the query: `ghost <> TRUE` is not semantically equivalent
    to `ghost IS NOT TRUE` (null semantics).
    
    The reason we add an index particularly intended for EE is that the EE
    query is going to have the additional part `AND bot_type IS NULL`
    whereas the CE query doesn't. Logically, it'd be enough to have an index
    for `ghost IS NOT TRUE`. However, on GitLab.com, the query planner makes
    poor choices when the additional `AND bot_type IS NULL` part is present:
    It goes for the index on `bot_type` and doesn't use the partial index.
    
    Note the existing index isn't being used at all according to GitLab.com
    index statistics. Hence we can first remove it and don't have to worry
    about the window of time without an index.
    
    Relates to https://gitlab.com/gitlab-org/gitlab-ce/issues/66770
    5b4108f0
schema.rb 204 KB