Query: explain SELECT
COALESCE(a2.n_nationkey, a1.p_size),
a1.p_size,
a2.n_nationkey
FROM part a1
LEFT JOIN nation a2 ON (a1.p_size) = (a2.n_nationkey)
+-------------------------------------------------------+
| Explain String                                        |
+-------------------------------------------------------+
| Per-Host Resource Reservation: Memory=136.00MB        |
| Per-Host Resource Estimates: Memory=10.00MB           |
|                                                       |
| F02:PLAN FRAGMENT [UNPARTITIONED] hosts=1 instances=1 |
| PLAN-ROOT SINK                                        |
| |  mem-estimate=0B mem-reservation=0B                 |
| |                                                     |
| 04:EXCHANGE [UNPARTITIONED]                           |
| |  mem-estimate=0B mem-reservation=0B                 |
| |  tuple-ids=0,1N row-size=6B cardinality=200000      |
| |                                                     |
| F00:PLAN FRAGMENT [RANDOM] hosts=3 instances=3        |
| 02:HASH JOIN [LEFT OUTER JOIN, BROADCAST]             |
| |  hash predicates: (a1.p_size) = (a2.n_nationkey)    |
| |  mem-estimate=56B mem-reservation=136.00MB          |
| |  tuple-ids=0,1N row-size=6B cardinality=200000      |
| |                                                     |
| |--03:EXCHANGE [BROADCAST]                            |
| |  |  mem-estimate=0B mem-reservation=0B              |
| |  |  tuple-ids=1 row-size=2B cardinality=25          |
| |  |                                                  |
| |  F01:PLAN FRAGMENT [RANDOM] hosts=3 instances=3     |
| |  01:SCAN KUDU [tpch_kudu.nation a2]                 |
| |     mem-estimate=0B mem-reservation=0B              |
| |     tuple-ids=1 row-size=2B cardinality=25          |
| |                                                     |
| 00:SCAN KUDU [tpch_kudu.part a1]                      |
|    mem-estimate=0B mem-reservation=0B                 |
|    tuple-ids=0 row-size=4B cardinality=200000         |
+-------------------------------------------------------+