gistfile1.txt

*************************** 2. row ***************************
    QUERY: SELECT SUM(alias2.col_varchar_nokey) , alias2.pk AS field2 FROM t1 AS alias1
STRAIGHT_JOIN t2 AS alias2 ON alias2.pk = alias1.col_int_key WHERE alias1.pk
GROUP BY field2 ORDER BY alias1.col_int_key,alias2.pk
OPT_TRACE: {
  "join_optimization": {
    "select #": 1,
    "steps": {
      "inner": {
        "select #": 1,
        "steps": [
          {
            "condition_processing": {
              "condition": "WHERE",
              "original_condition": "`test`.`alias1`.`pk` <> 0 and `test`.`alias2`.`pk` = `test`.`alias1`.`col_int_key`",
              "steps": [
                {
                  "transformation": "equality_propagation",
                  "subselect_evaluation": [],
                  "resulting_condition": "`test`.`alias1`.`pk` <> 0 and multiple equal(`test`.`alias2`.`pk`, `test`.`alias1`.`col_int_key`)-??"
                },
                {
                  "transformation": "constant_propagation",
                  "subselect_evaluation": [],
                  "resulting_condition": "`test`.`alias1`.`pk` <> 0 and multiple equal(`test`.`alias2`.`pk`, `test`.`alias1`.`col_int_key`)-??"
                },
                {
                  "transformation": "trivial_condition_removal",
                  "subselect_evaluation": [],
                  "resulting_condition": "`test`.`alias1`.`pk` <> 0 and multiple equal(`test`.`alias2`.`pk`, `test`.`alias1`.`col_int_key`)-??"
                }
              ]
            }
          },
          {
            "condition_processing": {
              "condition": "WHERE",
              "original_condition": "`test`.`alias1`.`pk` <> 0 and multiple equal(`test`.`alias2`.`pk`, `test`.`alias1`.`col_int_key`)-??",
              "steps": [
                {
                  "transformation": "equality_propagation",
                  "resulting_condition": "`test`.`alias1`.`pk` <> 0 and multiple equal(`test`.`alias2`.`pk`, `test`.`alias1`.`col_int_key`)-??"
                }
              ]
            }
          },
          {
            "ref_optimizer_key_uses": [
              {
                "table": "`test`.`t2` `alias2`",
                "field": "pk",
                "equals": "`test`.`alias1`.`col_int_key`",
                "null_rejecting": true
              }
            ]
          },
          {
            "rows_estimation": [
              {
                "table": "`test`.`t1` `alias1`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 20,
                    "cost": 7.1
                  }
                }
              },
              {
                "table": "`test`.`t2` `alias2`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 100,
                    "cost": 23.1
                  },
                  "potential_range_indexes": [
                    {
                      "index": "PRIMARY",
                      "usable": true,
                      "key_parts": ["pk"]
                    }
                  ],
                  "group_index_range": {
                    "chosen": false,
                    "cause": "not_single_table"
                  }
                }
              }
            ]
          },
          {
            "stage2": {
              "select #": 1,
              "steps": []
            }
          }
        ]
      }
    }
  }
]