Function lookup_join_hashmap 

pub(super) fn lookup_join_hashmap(
    build_hashmap: &dyn JoinHashMapType,
    build_side_values: &[ArrayRef],
    probe_side_values: &[ArrayRef],
    null_equality: NullEquality,
    hashes_buffer: &[u64],
    limit: usize,
    offset: (usize, Option<u64>),
) -> Result<(UInt64Array, UInt32Array, Option<(usize, Option<u64>)>)>

Executes lookups by hash against JoinHashMap and resolves potential hash collisions. Returns build/probe indices satisfying the equality condition, along with (optional) starting point for next iteration.

Example

For LEFT.b1 = RIGHT.b2: LEFT (build) Table:

 a1  b1  c1
 1   1   10
 3   3   30
 5   5   50
 7   7   70
 9   8   90
 11  8   110
 13   10  130

RIGHT (probe) Table:

 a2   b2  c2
 2    2   20
 4    4   40
 6    6   60
 8    8   80
10   10  100
12   10  120

The result is

"+----+----+-----+----+----+-----+",
"| a1 | b1 | c1  | a2 | b2 | c2  |",
"+----+----+-----+----+----+-----+",
"| 9  | 8  | 90  | 8  | 8  | 80  |",
"| 11 | 8  | 110 | 8  | 8  | 80  |",
"| 13 | 10 | 130 | 10 | 10 | 100 |",
"| 13 | 10 | 130 | 12 | 10 | 120 |",
"+----+----+-----+----+----+-----+"

And the result of build and probe indices are:

Build indices: 4, 5, 6, 6
Probe indices: 3, 3, 4, 5