Dave Gosselin 14191673f1 MDEV-40620: Name the kind of range a JOIN_TAB stands for ...

A JOIN_TAB that reads a temporary table standing for several other
tables owned a separately allocated JOIN_TAB_RANGE describing those
tables, and the only way to ask whether a JOIN_TAB had such a range was
to test that pointer.  The range is now a member of the JOIN_TAB and
carries the kind of range it is, so the question has a name,
has_bush_children.  st_nested_join::nest_type becomes an enumeration for
the same reason.

Asking whether a JOIN_TAB owned a range and asking whether that range
holds the inner tables of a materialized semi join were the same
question, so every place that reaches a semi join through a range's
first JOIN_TAB relied on a materialized semi join being the only thing a
range could hold.  is_sjm_nest now reads the kind, and the places that
reach a semi join that way either ask it or assert it.  Places that only
care whether a range exists at all keep asking that instead.

A kind is named for the range a materialized FULL JOIN nest will hold,
which an enclosing join's condition needs so that it sees a nest's rows
complete, including the rows the nest produced by null complementing.
Nothing produces one yet, so behaviour is unchanged.

2026-09-01 10:25:47 -04:00

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