On Sun, Sep 22, 2024 at 3:45 PM David Rowley <dgrowle...@gmail.com> wrote:
> I think the documents should also mention that disabling an index is a > useful way to verify an index is not being used before dropping it as > the index can be enabled again at the first sign that performance has > been effected. (It might also be good to mention that checking > pg_stat_user_indexes.idx_scan should be the first port of call when > checking for unused indexes) While reviewing Shayon's v14 patch, I had removed text (quoted below) from the ALTER INDEX docs that did not feel right in a command reference. I thought of reading up on the history/discussion of the patch, and now I see why Shayon chose to include an advice in ALTER INDEX docs. > + indexes. If performance degrades after making an index invisible, it can be > easily > + be made visible using <literal>VISIBLE</literal>. Before making an index > invisible, it's recommended > + to check > <structname>pg_stat_user_indexes</structname>.<structfield>idx_scan</structfield> > + to identify potentially unused indexes. I feel ALTER INDEX command reference doc is not the right place for this kind of operational advice. Is there a better place in documentation for this kind of advice? Or maybe it needs to be reworded to fit the command reference style? Best regards, Gurjeet http://Gurje.et
