Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2044 insertions, 0 deletions

diff --git a/mysql-test/main/explain_json.result b/mysql-test/main/explain_json.result
new file mode 100644
index 00000000..8eb7e5d5
--- /dev/null
+++ b/mysql-test/main/explain_json.result
@@ -0,0 +1,2044 @@
+drop table if exists t0,t1,t2;
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+explain format=json select * from t0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t0 where 1>2;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "message": "Impossible WHERE"
+    }
+  }
+}
+explain format=json select * from t0 where a<3;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t0.a < 3"
+        }
+      }
+    ]
+  }
+}
+# Try a basic join
+create table t1 (a int, b int, filler char(32), key(a));
+insert into t1 
+select 
+a.a + b.a* 10 + c.a * 100, 
+a.a + b.a* 10 + c.a * 100,
+'filler'
+from t0 a, t0 b, t0 c;
+explain format=json select * from t0,t1 where t1.a=t0.a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t0.a is not null"
+        }
+      },
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ref",
+          "possible_keys": ["a"],
+          "key": "a",
+          "key_length": "5",
+          "used_key_parts": ["a"],
+          "ref": ["test.t0.a"],
+          "rows": 1,
+          "filtered": 100
+        }
+      }
+    ]
+  }
+}
+# Try range and index_merge
+create table t2 (a1 int, a2 int, b1 int, b2 int, key(a1,a2), key(b1,b2));
+insert into t2 select a,a,a,a from t1;
+explain format=json select * from t2 where a1<5;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "range",
+          "possible_keys": ["a1"],
+          "key": "a1",
+          "key_length": "5",
+          "used_key_parts": ["a1"],
+          "rows": 5,
+          "filtered": 100,
+          "index_condition": "t2.a1 < 5"
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t2 where a1=1 or b1=2;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "index_merge",
+          "possible_keys": ["a1", "b1"],
+          "key_length": "5,5",
+          "index_merge": {
+            "sort_union": [
+              {
+                "range": {
+                  "key": "a1",
+                  "used_key_parts": ["a1"]
+                }
+              },
+              {
+                "range": {
+                  "key": "b1",
+                  "used_key_parts": ["b1"]
+                }
+              }
+            ]
+          },
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "t2.a1 = 1 or t2.b1 = 2"
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t2 where a1=1 or (b1=2 and b2=3);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "index_merge",
+          "possible_keys": ["a1", "b1"],
+          "key_length": "5,10",
+          "index_merge": {
+            "sort_union": [
+              {
+                "range": {
+                  "key": "a1",
+                  "used_key_parts": ["a1"]
+                }
+              },
+              {
+                "range": {
+                  "key": "b1",
+                  "used_key_parts": ["b1", "b2"]
+                }
+              }
+            ]
+          },
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "t2.a1 = 1 or t2.b1 = 2 and t2.b2 = 3"
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t2 where (a1=1 and a2=1) or 
+(b1=2 and b2=1);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "index_merge",
+          "possible_keys": ["a1", "b1"],
+          "key_length": "10,10",
+          "index_merge": {
+            "union": [
+              {
+                "range": {
+                  "key": "a1",
+                  "used_key_parts": ["a1", "a2"]
+                }
+              },
+              {
+                "range": {
+                  "key": "b1",
+                  "used_key_parts": ["b1", "b2"]
+                }
+              }
+            ]
+          },
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "t2.a1 = 1 and t2.a2 = 1 or t2.b1 = 2 and t2.b2 = 1"
+        }
+      }
+    ]
+  }
+}
+# Try ref access on two key components
+explain format=json select * from t0,t2 where t2.b1=t0.a and t2.b2=4;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t0.a is not null"
+        }
+      },
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "ref",
+          "possible_keys": ["b1"],
+          "key": "b1",
+          "key_length": "10",
+          "used_key_parts": ["b1", "b2"],
+          "ref": ["test.t0.a", "const"],
+          "rows": 1,
+          "filtered": 100
+        }
+      }
+    ]
+  }
+}
+drop table t1,t2;
+#
+# Try a UNION
+#
+explain format=json select * from t0 A union     select * from t0 B;
+EXPLAIN
+{
+  "query_block": {
+    "union_result": {
+      "table_name": "<union1,2>",
+      "access_type": "ALL",
+      "query_specifications": [
+        {
+          "query_block": {
+            "select_id": 1,
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "A",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100
+                }
+              }
+            ]
+          }
+        },
+        {
+          "query_block": {
+            "select_id": 2,
+            "operation": "UNION",
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "B",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100
+                }
+              }
+            ]
+          }
+        }
+      ]
+    }
+  }
+}
+explain format=json select * from t0 A union all select * from t0 B;
+EXPLAIN
+{
+  "query_block": {
+    "union_result": {
+      "query_specifications": [
+        {
+          "query_block": {
+            "select_id": 1,
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "A",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100
+                }
+              }
+            ]
+          }
+        },
+        {
+          "query_block": {
+            "select_id": 2,
+            "operation": "UNION",
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "B",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100
+                }
+              }
+            ]
+          }
+        }
+      ]
+    }
+  }
+}
+#
+# Subqueries
+#
+create table t1 (a int, b int);
+insert into t1 select a,a from t0;
+explain format=json select a, a > (select max(b) from t1 where t1.b=t0.a) from t0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "expression_cache": {
+          "state": "uninitialized",
+          "query_block": {
+            "select_id": 2,
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "t1",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100,
+                  "attached_condition": "t1.b = t0.a"
+                }
+              }
+            ]
+          }
+        }
+      }
+    ]
+  }
+}
+explain format=json 
+select * from t0 where 
+a > (select max(b) from t1 where t1.b=t0.a) or a < 3 ;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t0.a > (subquery#2) or t0.a < 3"
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "expression_cache": {
+          "state": "uninitialized",
+          "query_block": {
+            "select_id": 2,
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "t1",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100,
+                  "attached_condition": "t1.b = t0.a"
+                }
+              }
+            ]
+          }
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+#
+# Join buffering
+#
+create table t1 (a int, b int);
+insert into t1 select tbl1.a+10*tbl2.a, tbl1.a+10*tbl2.a from t0 tbl1, t0 tbl2;
+explain format=json
+select * from t1 tbl1, t1 tbl2 where tbl1.a=tbl2.a and tbl1.b < 3 and tbl2.b < 5;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "tbl1",
+          "access_type": "ALL",
+          "rows": 100,
+          "filtered": 100,
+          "attached_condition": "tbl1.b < 3"
+        }
+      },
+      {
+        "block-nl-join": {
+          "table": {
+            "table_name": "tbl2",
+            "access_type": "ALL",
+            "rows": 100,
+            "filtered": 100,
+            "attached_condition": "tbl2.b < 5"
+          },
+          "buffer_type": "flat",
+          "buffer_size": "1Kb",
+          "join_type": "BNL",
+          "attached_condition": "tbl2.a = tbl1.a"
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+#
+# Single-table UPDATE/DELETE, INSERT
+#
+explain format=json delete from t0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "message": "Deleting all rows"
+    }
+  }
+}
+explain format=json delete from t0 where 1 > 2;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "message": "Impossible WHERE"
+    }
+  }
+}
+explain format=json delete from t0 where a < 3;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "delete": 1,
+      "table_name": "t0",
+      "access_type": "ALL",
+      "rows": 10,
+      "attached_condition": "t0.a < 3"
+    }
+  }
+}
+explain format=json update t0 set a=3 where a in (2,3,4);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "update": 1,
+      "table_name": "t0",
+      "access_type": "ALL",
+      "rows": 10,
+      "attached_condition": "t0.a in (2,3,4)"
+    }
+  }
+}
+explain format=json insert into t0 values (1);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "table_name": "t0"
+    }
+  }
+}
+create table t1 like t0;
+explain format=json insert into t1 values ((select max(a) from t0));
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "table_name": "t1"
+    },
+    "subqueries": [
+      {
+        "query_block": {
+          "select_id": 2,
+          "nested_loop": [
+            {
+              "table": {
+                "table_name": "t0",
+                "access_type": "ALL",
+                "rows": 10,
+                "filtered": 100
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+#
+# A derived table
+#
+create table t1 (a int, b int);
+insert into t1 select a,a from t0;
+explain format=json
+select * from (select a, count(*) as cnt from t1 group by a) as tbl
+where cnt>0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "tbl.cnt > 0",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "having_condition": "cnt > 0",
+              "filesort": {
+                "sort_key": "t1.a",
+                "temporary_table": {
+                  "nested_loop": [
+                    {
+                      "table": {
+                        "table_name": "t1",
+                        "access_type": "ALL",
+                        "rows": 10,
+                        "filtered": 100
+                      }
+                    }
+                  ]
+                }
+              }
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+explain format=json
+select * from (select a, count(*) as cnt from t1 group by a) as tbl1, t1 as
+tbl2 where cnt=tbl2.a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "tbl2",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "tbl2.a is not null"
+        }
+      },
+      {
+        "table": {
+          "table_name": "<derived2>",
+          "access_type": "ref",
+          "possible_keys": ["key0"],
+          "key": "key0",
+          "key_length": "8",
+          "used_key_parts": ["cnt"],
+          "ref": ["test.tbl2.a"],
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "tbl1.cnt = tbl2.a",
+          "materialized": {
+            "query_block": {
+              "select_id": 2,
+              "filesort": {
+                "sort_key": "t1.a",
+                "temporary_table": {
+                  "nested_loop": [
+                    {
+                      "table": {
+                        "table_name": "t1",
+                        "access_type": "ALL",
+                        "rows": 10,
+                        "filtered": 100
+                      }
+                    }
+                  ]
+                }
+              }
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+#
+# Non-merged semi-join (aka JTBM)
+#
+explain format=json 
+select * from t1 where a in (select max(a) from t1 group by b);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t1.a is not null"
+        }
+      },
+      {
+        "table": {
+          "table_name": "<subquery2>",
+          "access_type": "eq_ref",
+          "possible_keys": ["distinct_key"],
+          "key": "distinct_key",
+          "key_length": "4",
+          "used_key_parts": ["max(a)"],
+          "ref": ["test.t1.a"],
+          "rows": 1,
+          "filtered": 100,
+          "materialized": {
+            "unique": 1,
+            "query_block": {
+              "select_id": 2,
+              "temporary_table": {
+                "nested_loop": [
+                  {
+                    "table": {
+                      "table_name": "t1",
+                      "access_type": "ALL",
+                      "rows": 10,
+                      "filtered": 100
+                    }
+                  }
+                ]
+              }
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+#
+# Semi-join Materialization
+#
+create table t2 like t1;
+insert into t2 select * from t1;
+explain format=json
+select * from t1,t2 where t1.a in ( select a from t0);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "const_condition": "1",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      },
+      {
+        "table": {
+          "table_name": "<subquery2>",
+          "access_type": "eq_ref",
+          "possible_keys": ["distinct_key"],
+          "key": "distinct_key",
+          "key_length": "4",
+          "used_key_parts": ["a"],
+          "ref": ["func"],
+          "rows": 1,
+          "filtered": 100,
+          "materialized": {
+            "unique": 1,
+            "query_block": {
+              "select_id": 2,
+              "nested_loop": [
+                {
+                  "table": {
+                    "table_name": "t0",
+                    "access_type": "ALL",
+                    "rows": 10,
+                    "filtered": 100
+                  }
+                }
+              ]
+            }
+          }
+        }
+      },
+      {
+        "block-nl-join": {
+          "table": {
+            "table_name": "t2",
+            "access_type": "ALL",
+            "rows": 10,
+            "filtered": 100
+          },
+          "buffer_type": "flat",
+          "buffer_size": "1Kb",
+          "join_type": "BNL"
+        }
+      }
+    ]
+  }
+}
+# 
+# First-Match
+# 
+explain
+select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; FirstMatch(t2); Using join buffer (flat, BNL join)
+explain format=json
+select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      },
+      {
+        "block-nl-join": {
+          "table": {
+            "table_name": "t1",
+            "access_type": "ALL",
+            "rows": 10,
+            "filtered": 100,
+            "first_match": "t2"
+          },
+          "buffer_type": "flat",
+          "buffer_size": "141",
+          "join_type": "BNL",
+          "attached_condition": "t1.b = t2.b and t1.a = t2.a"
+        }
+      }
+    ]
+  }
+}
+# 
+# Duplicate Weedout
+# 
+set @tmp= @@optimizer_switch;
+set optimizer_switch='firstmatch=off';
+explain
+select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	10	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary; End temporary; Using join buffer (flat, BNL join)
+explain format=json
+select * from t2 where t2.a in ( select a from t1 where t1.b=t2.b);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      },
+      {
+        "duplicates_removal": [
+          {
+            "block-nl-join": {
+              "table": {
+                "table_name": "t1",
+                "access_type": "ALL",
+                "rows": 10,
+                "filtered": 100
+              },
+              "buffer_type": "flat",
+              "buffer_size": "206",
+              "join_type": "BNL",
+              "attached_condition": "t1.b = t2.b and t1.a = t2.a"
+            }
+          }
+        ]
+      }
+    ]
+  }
+}
+set optimizer_switch=@tmp;
+drop table t1,t2;
+#
+# MRR for range access (no BKA, just MRR)
+#
+create table t1 (a int, b int, key(a));
+insert into t1 select tbl1.a+10*tbl2.a, 12345 from t0 tbl1, t0 tbl2;
+set @tmp= @@optimizer_switch;
+set optimizer_switch='mrr=on,mrr_sort_keys=on';
+explain format=json select * from t1 where a < 3;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "range",
+          "possible_keys": ["a"],
+          "key": "a",
+          "key_length": "5",
+          "used_key_parts": ["a"],
+          "rows": 2,
+          "filtered": 100,
+          "index_condition": "t1.a < 3",
+          "mrr_type": "Rowid-ordered scan"
+        }
+      }
+    ]
+  }
+}
+# 'Range checked for each record'
+set optimizer_switch=@tmp;
+explain format=json
+select * from t1 tbl1, t1 tbl2 where tbl2.a < tbl1.b;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "tbl1",
+          "access_type": "ALL",
+          "rows": 100,
+          "filtered": 100
+        }
+      },
+      {
+        "range-checked-for-each-record": {
+          "keys": ["a"],
+          "table": {
+            "table_name": "tbl2",
+            "access_type": "ALL",
+            "possible_keys": ["a"],
+            "rows": 100,
+            "filtered": 100
+          }
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+drop table t0;
+#
+# MDEV-7265: "Full scan on NULL key", the join case
+#
+CREATE TABLE t1 (a INT, KEY(a));
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+EXPLAIN FORMAT=JSON SELECT * FROM t1 AS outer_t1 WHERE a <> ALL ( SELECT a FROM t1, t2 WHERE b <> outer_t1.a );
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "outer_t1",
+          "access_type": "index",
+          "key": "a",
+          "key_length": "5",
+          "used_key_parts": ["a"],
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "!<in_optimizer>(outer_t1.a,<exists>(subquery#2))",
+          "using_index": true
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "query_block": {
+          "select_id": 2,
+          "having_condition": "trigcond(t1.a is null)",
+          "nested_loop": [
+            {
+              "full-scan-on-null_key": {
+                "table": {
+                  "table_name": "t1",
+                  "access_type": "ref_or_null",
+                  "possible_keys": ["a"],
+                  "key": "a",
+                  "key_length": "5",
+                  "used_key_parts": ["a"],
+                  "ref": ["func"],
+                  "rows": 2,
+                  "filtered": 100,
+                  "attached_condition": "trigcond(<cache>(outer_t1.a) = t1.a or t1.a is null)",
+                  "using_index": true
+                }
+              }
+            },
+            {
+              "block-nl-join": {
+                "table": {
+                  "table_name": "t2",
+                  "access_type": "ALL",
+                  "rows": 2,
+                  "filtered": 100
+                },
+                "buffer_type": "flat",
+                "buffer_size": "65",
+                "join_type": "BNL",
+                "attached_condition": "t2.b <> outer_t1.a"
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}
+DROP TABLE t1,t2;
+#
+# Join's constant expression
+#
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1(a int, b int);
+insert into t1 select tbl1.a+10*tbl2.a, 1234 from t0 tbl1, t0 tbl2;
+explain format=json 
+select * from t0 
+where 
+20000 > all (select max(tbl1.a + tbl2.a)
+from t1 tbl1, t1 tbl2 where tbl1.b=tbl2.b);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "const_condition": "<not>(<in_optimizer>(20000,<max>(subquery#2) >= 20000))",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "query_block": {
+          "select_id": 2,
+          "nested_loop": [
+            {
+              "table": {
+                "table_name": "tbl1",
+                "access_type": "ALL",
+                "rows": 100,
+                "filtered": 100
+              }
+            },
+            {
+              "block-nl-join": {
+                "table": {
+                  "table_name": "tbl2",
+                  "access_type": "ALL",
+                  "rows": 100,
+                  "filtered": 100
+                },
+                "buffer_type": "flat",
+                "buffer_size": "1Kb",
+                "join_type": "BNL",
+                "attached_condition": "tbl2.b = tbl1.b"
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+drop table t0;
+# 
+# MDEV-7264: Assertion `0' failed in subselect_engine::get_identifier() on EXPLAIN JSON
+# 
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE a <> ALL ( SELECT b FROM t2 );
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "!<in_optimizer>(t1.a,t1.a in (subquery#2))"
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "query_block": {
+          "select_id": 2,
+          "nested_loop": [
+            {
+              "table": {
+                "table_name": "t2",
+                "access_type": "ALL",
+                "rows": 2,
+                "filtered": 100
+              }
+            }
+          ]
+        }
+      }
+    ]
+  }
+}
+DROP TABLE t1, t2;
+#
+# MDEV-7927: Server crashes in in Time_and_counter_tracker::incr_loops
+#
+CREATE TABLE t1 (i INT);
+INSERT INTO t1 VALUES (1),(2);
+EXPLAIN SELECT * FROM t1 WHERE 3 IN ( SELECT 4 UNION SELECT 5 );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+DROP TABLE t1;
+#
+# MDEV-7860: EXPLAIN FORMAT=JSON crashes for loose scan query
+#
+create table t2(a int);
+insert into t2 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (a int, b int, c int, d int, key(a,b,c));
+insert into t1 select  A.a, B.a, C.a, D.a from t2 A, t2 B, t2 C, t2 D;
+explain select count(distinct b) from t1 group by a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	NULL	a	10	NULL	101	Using index for group-by
+explain format=json select count(distinct b) from t1 group by a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "range",
+          "key": "a",
+          "key_length": "10",
+          "used_key_parts": ["a", "b"],
+          "rows": 101,
+          "filtered": 100,
+          "using_index_for_group_by": true
+        }
+      }
+    ]
+  }
+}
+analyze format=json select count(distinct b) from t1 group by a;
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "range",
+          "key": "a",
+          "key_length": "10",
+          "used_key_parts": ["a", "b"],
+          "r_loops": 1,
+          "rows": 101,
+          "r_rows": 100,
+          "r_table_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": 100,
+          "using_index_for_group_by": true
+        }
+      }
+    ]
+  }
+}
+drop table t1,t2;
+#
+# Try both variants of LooseScan (data/queries borrowed from group_min_max.test)
+#
+create table t1 (
+a1 char(64), a2 char(64), b char(16), c char(16) not null, d char(16), dummy char(248) default ' '
+);
+insert into t1 (a1, a2, b, c, d) values
+('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
+('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
+('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
+('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
+('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
+('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
+('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
+('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
+('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
+('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
+('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
+('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
+('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
+('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
+('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
+('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4'),
+('a','a','a','a111','xy1'),('a','a','a','b111','xy2'),('a','a','a','c111','xy3'),('a','a','a','d111','xy4'),
+('a','a','b','e112','xy1'),('a','a','b','f112','xy2'),('a','a','b','g112','xy3'),('a','a','b','h112','xy4'),
+('a','b','a','i121','xy1'),('a','b','a','j121','xy2'),('a','b','a','k121','xy3'),('a','b','a','l121','xy4'),
+('a','b','b','m122','xy1'),('a','b','b','n122','xy2'),('a','b','b','o122','xy3'),('a','b','b','p122','xy4'),
+('b','a','a','a211','xy1'),('b','a','a','b211','xy2'),('b','a','a','c211','xy3'),('b','a','a','d211','xy4'),
+('b','a','b','e212','xy1'),('b','a','b','f212','xy2'),('b','a','b','g212','xy3'),('b','a','b','h212','xy4'),
+('b','b','a','i221','xy1'),('b','b','a','j221','xy2'),('b','b','a','k221','xy3'),('b','b','a','l221','xy4'),
+('b','b','b','m222','xy1'),('b','b','b','n222','xy2'),('b','b','b','o222','xy3'),('b','b','b','p222','xy4'),
+('c','a','a','a311','xy1'),('c','a','a','b311','xy2'),('c','a','a','c311','xy3'),('c','a','a','d311','xy4'),
+('c','a','b','e312','xy1'),('c','a','b','f312','xy2'),('c','a','b','g312','xy3'),('c','a','b','h312','xy4'),
+('c','b','a','i321','xy1'),('c','b','a','j321','xy2'),('c','b','a','k321','xy3'),('c','b','a','l321','xy4'),
+('c','b','b','m322','xy1'),('c','b','b','n322','xy2'),('c','b','b','o322','xy3'),('c','b','b','p322','xy4'),
+('d','a','a','a411','xy1'),('d','a','a','b411','xy2'),('d','a','a','c411','xy3'),('d','a','a','d411','xy4'),
+('d','a','b','e412','xy1'),('d','a','b','f412','xy2'),('d','a','b','g412','xy3'),('d','a','b','h412','xy4'),
+('d','b','a','i421','xy1'),('d','b','a','j421','xy2'),('d','b','a','k421','xy3'),('d','b','a','l421','xy4'),
+('d','b','b','m422','xy1'),('d','b','b','n422','xy2'),('d','b','b','o422','xy3'),('d','b','b','p422','xy4');
+create index idx_t1_0 on t1 (a1);
+create index idx_t1_1 on t1 (a1,a2,b,c);
+create index idx_t1_2 on t1 (a1,a2,b);
+analyze table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	Table is already up to date
+explain select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
+explain select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	NULL	idx_t1_1	163	NULL	65	Using where; Using index for group-by
+explain format=json select count(distinct a1,a2,b) from t1 where (a2 >= 'b') and (b = 'a');
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "range",
+          "key": "idx_t1_1",
+          "key_length": "147",
+          "used_key_parts": ["a1", "a2", "b"],
+          "rows": 17,
+          "filtered": 100,
+          "attached_condition": "t1.b = 'a' and t1.a2 >= 'b'",
+          "using_index_for_group_by": true
+        }
+      }
+    ]
+  }
+}
+explain format=json select count(distinct a1,a2,b,c) from t1 where (a2 >= 'b') and (b = 'a') and (c = 'i121');
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "range",
+          "key": "idx_t1_1",
+          "key_length": "163",
+          "used_key_parts": ["a1", "a2", "b", "c"],
+          "rows": 65,
+          "filtered": 100,
+          "attached_condition": "t1.b = 'a' and t1.c = 'i121' and t1.a2 >= 'b'",
+          "using_index_for_group_by": true
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+#
+# MDEV-8786 Wrong result for SELECT FORMAT=JSON * FROM t1 WHERE a=_latin1 0xDF
+#
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1);
+INSERT INTO t1 VALUES ('a'),('b');
+EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE a=_latin1 0xDF;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "t1.a = _latin1'\xDF'"
+        }
+      }
+    ]
+  }
+}
+DROP TABLE t1;
+#
+# MDEV-8785 Wrong results for EXPLAIN EXTENDED...WHERE NULLIF(latin1_col, _utf8'a' COLLATE utf8_bin) IS NOT NULL
+#
+CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET latin1);
+INSERT INTO t1 VALUES ('a'),('A');
+EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE NULLIF(a,_utf8'a' COLLATE utf8_bin);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100,
+          "attached_condition": "(case when convert(t1.a using utf8mb3) = <cache>(_utf8mb3'a' collate utf8mb3_bin) then NULL else t1.a end)"
+        }
+      }
+    ]
+  }
+}
+DROP TABLE t1;
+#
+# MDEV-7970: EXPLAIN FORMAT=JSON does not print HAVING
+#
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3);
+create table t1(a int);
+insert into t1 select A.a + B.a* 10 + C.a * 100 from t0 A, t0 B, t0 C;
+create table t2 (
+a int, 
+b int, 
+key (a)
+);
+insert into t2 select A.a*1000 + B.a, A.a*1000 + B.a from t0 A, t1 B;
+# normal HAVING
+explain format=json select a, max(b) as TOP from t2 group by a having TOP > a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "having_condition": "TOP > t2.a",
+    "filesort": {
+      "sort_key": "t2.a",
+      "temporary_table": {
+        "nested_loop": [
+          {
+            "table": {
+              "table_name": "t2",
+              "access_type": "ALL",
+              "rows": 256,
+              "filtered": 100
+            }
+          }
+        ]
+      }
+    }
+  }
+}
+# HAVING is always TRUE (not printed)
+explain format=json select a, max(b) as TOP from t2 group by a having 1<>2;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "filesort": {
+      "sort_key": "t2.a",
+      "temporary_table": {
+        "nested_loop": [
+          {
+            "table": {
+              "table_name": "t2",
+              "access_type": "ALL",
+              "rows": 256,
+              "filtered": 100
+            }
+          }
+        ]
+      }
+    }
+  }
+}
+# HAVING is always FALSE (intercepted by message)
+explain format=json select a, max(b) as TOP from t2 group by a having 1=2;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "message": "Impossible HAVING"
+    }
+  }
+}
+# HAVING is absent
+explain format=json select a, max(b) as TOP from t2 group by a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "filesort": {
+      "sort_key": "t2.a",
+      "temporary_table": {
+        "nested_loop": [
+          {
+            "table": {
+              "table_name": "t2",
+              "access_type": "ALL",
+              "rows": 256,
+              "filtered": 100
+            }
+          }
+        ]
+      }
+    }
+  }
+}
+drop table t0, t1, t2;
+#
+# MDEV-8829: Assertion `0' failed in Explain_table_access::tag_to_json
+#
+# Check ET_CONST_ROW_NOT_FOUND
+create table t1 (i int) engine=myisam;
+explain 
+select * from t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	0	Const row not found
+explain format=json
+select * from t1;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "system",
+          "rows": 0,
+          "filtered": 0,
+          "const_row_not_found": true
+        }
+      }
+    ]
+  }
+}
+analyze format=json 
+select * from t1;
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "message": "no matching row in const table"
+    }
+  }
+}
+drop table t1;
+# Check ET_IMPOSSIBLE_ON_CONDITION
+create table t1 (a int);
+create table t2 (pk int primary key);
+insert into t1 values (1),(2);
+insert into t2 values (1),(2);
+explain 
+select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	const	PRIMARY	NULL	NULL	NULL	1	Impossible ON condition
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+explain format=json
+select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "const_condition": "1",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "const",
+          "possible_keys": ["PRIMARY"],
+          "rows": 1,
+          "filtered": 100,
+          "impossible_on_condition": true
+        }
+      },
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100
+        }
+      }
+    ]
+  }
+}
+analyze format=json
+select * from t1 left join t2 on t2.pk > 10 and t2.pk < 0;
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "const_condition": "1",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "const",
+          "possible_keys": ["PRIMARY"],
+          "r_loops": 0,
+          "rows": 1,
+          "r_rows": null,
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": null,
+          "impossible_on_condition": true
+        }
+      },
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "r_loops": 1,
+          "rows": 2,
+          "r_rows": 2,
+          "r_table_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": 100
+        }
+      }
+    ]
+  }
+}
+# Check ET_NOT_EXISTS:
+explain
+select * from t1 left join t2 on t2.pk=t1.a where  t2.pk is null;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	Using where; Using index; Not exists
+explain format=json
+select * from t1 left join t2 on t2.pk=t1.a where  t2.pk is null;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100
+        }
+      },
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "eq_ref",
+          "possible_keys": ["PRIMARY"],
+          "key": "PRIMARY",
+          "key_length": "4",
+          "used_key_parts": ["pk"],
+          "ref": ["test.t1.a"],
+          "rows": 1,
+          "filtered": 100,
+          "attached_condition": "trigcond(t2.pk is null) and trigcond(trigcond(t1.a is not null))",
+          "using_index": true,
+          "not_exists": true
+        }
+      }
+    ]
+  }
+}
+analyze format=json
+select * from t1 left join t2 on t2.pk=t1.a where  t2.pk is null;
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "r_loops": 1,
+          "rows": 2,
+          "r_rows": 2,
+          "r_table_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": 100
+        }
+      },
+      {
+        "table": {
+          "table_name": "t2",
+          "access_type": "eq_ref",
+          "possible_keys": ["PRIMARY"],
+          "key": "PRIMARY",
+          "key_length": "4",
+          "used_key_parts": ["pk"],
+          "ref": ["test.t1.a"],
+          "r_loops": 2,
+          "rows": 1,
+          "r_rows": 1,
+          "r_table_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": 100,
+          "attached_condition": "trigcond(t2.pk is null) and trigcond(trigcond(t1.a is not null))",
+          "using_index": true,
+          "not_exists": true
+        }
+      }
+    ]
+  }
+}
+# Check ET_DISTINCT
+explain
+select distinct t1.a from t1 join t2 on t2.pk=t1.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	Using where; Using temporary
+1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.a	1	Using index; Distinct
+explain format=json
+select distinct t1.a from t1 join t2 on t2.pk=t1.a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "temporary_table": {
+      "nested_loop": [
+        {
+          "table": {
+            "table_name": "t1",
+            "access_type": "ALL",
+            "rows": 2,
+            "filtered": 100,
+            "attached_condition": "t1.a is not null"
+          }
+        },
+        {
+          "table": {
+            "table_name": "t2",
+            "access_type": "eq_ref",
+            "possible_keys": ["PRIMARY"],
+            "key": "PRIMARY",
+            "key_length": "4",
+            "used_key_parts": ["pk"],
+            "ref": ["test.t1.a"],
+            "rows": 1,
+            "filtered": 100,
+            "using_index": true,
+            "distinct": true
+          }
+        }
+      ]
+    }
+  }
+}
+analyze format=json
+select distinct t1.a from t1 join t2 on t2.pk=t1.a;
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "temporary_table": {
+      "nested_loop": [
+        {
+          "table": {
+            "table_name": "t1",
+            "access_type": "ALL",
+            "r_loops": 1,
+            "rows": 2,
+            "r_rows": 2,
+            "r_table_time_ms": "REPLACED",
+            "r_other_time_ms": "REPLACED",
+            "r_engine_stats": REPLACED,
+            "filtered": 100,
+            "r_filtered": 100,
+            "attached_condition": "t1.a is not null"
+          }
+        },
+        {
+          "table": {
+            "table_name": "t2",
+            "access_type": "eq_ref",
+            "possible_keys": ["PRIMARY"],
+            "key": "PRIMARY",
+            "key_length": "4",
+            "used_key_parts": ["pk"],
+            "ref": ["test.t1.a"],
+            "r_loops": 2,
+            "rows": 1,
+            "r_rows": 1,
+            "r_table_time_ms": "REPLACED",
+            "r_other_time_ms": "REPLACED",
+            "r_engine_stats": REPLACED,
+            "filtered": 100,
+            "r_filtered": 100,
+            "using_index": true,
+            "distinct": true
+          }
+        }
+      ]
+    }
+  }
+}
+drop table t1,t2;
+# Check ET_USING_INDEX_CONDITION_BKA
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2(a int);
+insert into t2 select A.a + B.a* 10 + C.a * 100 from t1 A, t1 B, t1 C;
+create table t3(a int, b int);
+insert into t3 select a,a from t1;
+create table t4(a int, b int, c int, filler char(100), key (a,b));
+insert into t4 select a,a,a, 'filler-data' from t2;
+set @tmp_optimizer_switch=@@optimizer_switch;
+set @tmp_join_cache_level=@@join_cache_level;
+set optimizer_switch='mrr=on';
+set join_cache_level=6;
+explain
+select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	10	Using where
+1	SIMPLE	t4	ref	a	a	5	test.t3.a	1	Using index condition(BKA); Using join buffer (flat, BKA join); Rowid-ordered scan
+explain format=json
+select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t3",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100,
+          "attached_condition": "t3.a is not null"
+        }
+      },
+      {
+        "block-nl-join": {
+          "table": {
+            "table_name": "t4",
+            "access_type": "ref",
+            "possible_keys": ["a"],
+            "key": "a",
+            "key_length": "5",
+            "used_key_parts": ["a"],
+            "ref": ["test.t3.a"],
+            "rows": 1,
+            "filtered": 100,
+            "index_condition_bka": "t4.b + 1 <= t3.b + 1"
+          },
+          "buffer_type": "flat",
+          "buffer_size": "400",
+          "join_type": "BKA",
+          "mrr_type": "Rowid-ordered scan"
+        }
+      }
+    ]
+  }
+}
+analyze format=json
+select * from t3,t4 where t3.a=t4.a and (t4.b+1 <= t3.b+1);
+ANALYZE
+{
+  "query_optimization": {
+    "r_total_time_ms": "REPLACED"
+  },
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t3",
+          "access_type": "ALL",
+          "r_loops": 1,
+          "rows": 10,
+          "r_rows": 10,
+          "r_table_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_engine_stats": REPLACED,
+          "filtered": 100,
+          "r_filtered": 100,
+          "attached_condition": "t3.a is not null"
+        }
+      },
+      {
+        "block-nl-join": {
+          "table": {
+            "table_name": "t4",
+            "access_type": "ref",
+            "possible_keys": ["a"],
+            "key": "a",
+            "key_length": "5",
+            "used_key_parts": ["a"],
+            "ref": ["test.t3.a"],
+            "r_loops": 1,
+            "rows": 1,
+            "r_rows": 10,
+            "r_table_time_ms": "REPLACED",
+            "r_other_time_ms": "REPLACED",
+            "r_engine_stats": REPLACED,
+            "filtered": 100,
+            "r_filtered": 100,
+            "index_condition_bka": "t4.b + 1 <= t3.b + 1"
+          },
+          "buffer_type": "flat",
+          "buffer_size": "400",
+          "join_type": "BKA",
+          "mrr_type": "Rowid-ordered scan",
+          "r_loops": 10,
+          "r_filtered": 100,
+          "r_unpack_time_ms": "REPLACED",
+          "r_other_time_ms": "REPLACED",
+          "r_effective_rows": 1
+        }
+      }
+    ]
+  }
+}
+set optimizer_switch=@tmp_optimizer_switch;
+set join_cache_level=@tmp_join_cache_level;
+drop table t1,t2,t3,t4;
+#
+# MDEV-9652: EXPLAIN FORMAT=JSON should show outer_ref_cond
+#
+create table t0(a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (a int, b int);
+insert into t1 select a,a from t0;
+explain format=json 
+select a, (select max(a) from t1 where t0.a<5 and t1.b<t0.a) from t0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    ],
+    "subqueries": [
+      {
+        "expression_cache": {
+          "state": "uninitialized",
+          "query_block": {
+            "select_id": 2,
+            "outer_ref_condition": "t0.a < 5",
+            "nested_loop": [
+              {
+                "table": {
+                  "table_name": "t1",
+                  "access_type": "ALL",
+                  "rows": 10,
+                  "filtered": 100,
+                  "attached_condition": "t1.b < t0.a"
+                }
+              }
+            ]
+          }
+        }
+      }
+    ]
+  }
+}
+drop table t0,t1;
+#
+# MDEV-10844: EXPLAIN FORMAT=JSON doesn't show order direction for filesort
+#
+create table t1 (a int, b int);
+insert into t1 values (1,2),(3,4),(2,3);
+explain format=json select * from t1 order by a, b desc;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "read_sorted_file": {
+          "filesort": {
+            "sort_key": "t1.a, t1.b desc",
+            "table": {
+              "table_name": "t1",
+              "access_type": "ALL",
+              "rows": 3,
+              "filtered": 100
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t1 order by a desc, b desc;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "read_sorted_file": {
+          "filesort": {
+            "sort_key": "t1.a desc, t1.b desc",
+            "table": {
+              "table_name": "t1",
+              "access_type": "ALL",
+              "rows": 3,
+              "filtered": 100
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+explain format=json select * from t1 order by a desc, b ;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "read_sorted_file": {
+          "filesort": {
+            "sort_key": "t1.a desc, t1.b",
+            "table": {
+              "table_name": "t1",
+              "access_type": "ALL",
+              "rows": 3,
+              "filtered": 100
+            }
+          }
+        }
+      }
+    ]
+  }
+}
+drop table t1;
+#
+# MDEV-27204: [ERROR] Json_writer: a member name was expected, Assertion `got_name == named_item_expected()' failed
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+explain FORMAT=JSON 
+SELECT * FROM t1 t0 
+WHERE t0.a IN (SELECT t2.a FROM t1 t2 WHERE t0.a IN (SELECT t3.a FROM t1 t3));
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "nested_loop": [
+      {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 2,
+          "filtered": 100
+        }
+      },
+      {
+        "duplicates_removal": [
+          {
+            "block-nl-join": {
+              "table": {
+                "table_name": "t2",
+                "access_type": "ALL",
+                "rows": 2,
+                "filtered": 100
+              },
+              "buffer_type": "flat",
+              "buffer_size": "152",
+              "join_type": "BNL",
+              "attached_condition": "t2.a = t0.a"
+            }
+          },
+          {
+            "block-nl-join": {
+              "table": {
+                "table_name": "t3",
+                "access_type": "ALL",
+                "rows": 2,
+                "filtered": 100
+              },
+              "buffer_type": "incremental",
+              "buffer_size": "109",
+              "join_type": "BNL",
+              "attached_condition": "t3.a = t0.a"
+            }
+          }
+        ]
+      }
+    ]
+  }
+}
+DROP TABLE t1;
+#
+# MDEV-27206: [ERROR] Duplicated key: cause, Assertion `is_uniq_key' failed with optimizer trace
+#
+CREATE TABLE t1 (a INT) ENGINE=MyISAM;
+CREATE TABLE t2 (pk TIME, b INT, primary key (pk), key (b)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+('00:13:33',0),('00:13:34',1),('00:13:35',2),('00:13:36',3),
+('00:13:37',4),('00:13:38',5),('00:13:39',6),('00:13:40',7),
+('00:13:41',8),('00:13:42',9);
+SET optimizer_trace = 'enabled=on';
+SELECT * FROM t1 WHERE a IN ( SELECT b FROM t2 INNER JOIN t1 ON (a = pk) );
+a
+DROP TABLE t1, t2;