Reedy: Is anybody actually "tracking" this, seeing four tickets before #30000 as dependencies?
Missing indexes sounds like "MediaWiki > Database" with "schema-change" keyword, and inefficient queries sounds like "performance" keyword.

What is this tracking bug good for?

Reedy: Is anybody actually "tracking" this, seeing four tickets before #30000 as dependencies?
Missing indexes sounds like "MediaWiki > Database" with "schema-change" keyword, and inefficient queries sounds like "performance" keyword.

What is this tracking bug good for?

(In reply to Andre Klapper from comment #2)

Reedy: Is anybody actually "tracking" this, seeing four tickets before
#30000 as dependencies?

Not all inefficient queries are equally important. There's probably more than a couple low priority inefficient queries that just aren't triggered very often

Missing indexes sounds like "MediaWiki > Database" with "schema-change"
keyword, and inefficient queries sounds like "performance" keyword.

Sure, adding an index is one type of schema change. Arguably this should track a subset of bugs marked as schema change. Adding an index isn't the only way to fix a query, and sometimes its unclear what the best approach is. Additionally schema change bugs include bugs that require a schema change in order to enable, where this is tracking only already existing things which are inefficient due to the current schema.

What is this tracking bug good for?

Probably about as good as most tracking bugs. Whether or not tracking bugs are useful in general is probably something that could be debated.