diff --git a/mysql-test/main/analyze_format_json.result b/mysql-test/main/analyze_format_json.result
index fc643d1a8af..abe3fab4643 100644
--- a/mysql-test/main/analyze_format_json.result
+++ b/mysql-test/main/analyze_format_json.result
@@ -151,7 +151,9 @@ ANALYZE
       "buffer_type": "flat",
       "buffer_size": "1Kb",
       "join_type": "BNL",
-      "r_filtered": 100
+      "r_loops": 20,
+      "r_filtered": 100,
+      "r_effective_rows": 60
     }
   }
 }
@@ -192,7 +194,9 @@ ANALYZE
       "buffer_size": "1Kb",
       "join_type": "BNL",
       "attached_condition": "tbl1.c > tbl2.c",
-      "r_filtered": 15.83333333
+      "r_loops": 20,
+      "r_filtered": 15.83333333,
+      "r_effective_rows": 60
     }
   }
 }
@@ -652,7 +656,9 @@ ANALYZE
       "buffer_size": "65",
       "join_type": "BNL",
       "attached_condition": "<in_optimizer>(t2.b,t2.b in (subquery#2))",
-      "r_filtered": null
+      "r_loops": 2,
+      "r_filtered": null,
+      "r_effective_rows": 0
     },
     "subqueries": [
       {
@@ -742,7 +748,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "1",
               "join_type": "BNL",
-              "r_filtered": null
+              "r_loops": 2,
+              "r_filtered": null,
+              "r_effective_rows": 0
             },
             "subqueries": [
               {
@@ -774,7 +782,9 @@ ANALYZE
                       "buffer_size": "65",
                       "join_type": "BNL",
                       "attached_condition": "t2.f2 = t3.f3",
-                      "r_filtered": null
+                      "r_loops": 0,
+                      "r_filtered": null,
+                      "r_effective_rows": null
                     }
                   }
                 }
@@ -849,3 +859,123 @@ ANALYZE
   }
 }
 drop table t0,t1,t2;
+#
+# MDEV-30806: ANALYZE FORMAT=JSON: better support for BNL and BNL-H joins
+#
+create table t10 (
+a int,
+b int
+);
+insert into t10 select seq, seq/3 from seq_0_to_999;
+create table t11 (
+a int,
+b int
+);
+insert into t11 select seq, seq/5 from seq_0_to_999;
+analyze table t10,t11 persistent for all;
+Table	Op	Msg_type	Msg_text
+test.t10	analyze	status	Engine-independent statistics collected
+test.t10	analyze	status	OK
+test.t11	analyze	status	Engine-independent statistics collected
+test.t11	analyze	status	OK
+analyze format=json
+select * from t10, t11
+where
+t10.a < 700 and
+t11.a < 100
+and t10.b=t11.b;
+ANALYZE
+{
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "table": {
+      "table_name": "t11",
+      "access_type": "ALL",
+      "r_loops": 1,
+      "rows": 1000,
+      "r_rows": 1000,
+      "r_table_time_ms": "REPLACED",
+      "r_other_time_ms": "REPLACED",
+      "filtered": 10.15625,
+      "r_filtered": 10,
+      "attached_condition": "t11.a < 100"
+    },
+    "block-nl-join": {
+      "table": {
+        "table_name": "t10",
+        "access_type": "ALL",
+        "r_loops": 1,
+        "rows": 1000,
+        "r_rows": 1000,
+        "r_table_time_ms": "REPLACED",
+        "r_other_time_ms": "REPLACED",
+        "filtered": 70.3125,
+        "r_filtered": 70,
+        "attached_condition": "t10.a < 700"
+      },
+      "buffer_type": "flat",
+      "buffer_size": "1Kb",
+      "join_type": "BNL",
+      "attached_condition": "t10.b = t11.b",
+      "r_loops": 100,
+      "r_filtered": 0.424285714,
+      "r_effective_rows": 700
+    }
+  }
+}
+set @tmp=@@join_cache_level, join_cache_level=6;
+analyze format=json
+select * from t10, t11
+where
+t10.a < 700 and
+t11.a < 100
+and t10.b=t11.b;
+ANALYZE
+{
+  "query_block": {
+    "select_id": 1,
+    "r_loops": 1,
+    "r_total_time_ms": "REPLACED",
+    "table": {
+      "table_name": "t11",
+      "access_type": "ALL",
+      "r_loops": 1,
+      "rows": 1000,
+      "r_rows": 1000,
+      "r_table_time_ms": "REPLACED",
+      "r_other_time_ms": "REPLACED",
+      "filtered": 10.15625,
+      "r_filtered": 10,
+      "attached_condition": "t11.a < 100 and t11.b is not null"
+    },
+    "block-nl-join": {
+      "table": {
+        "table_name": "t10",
+        "access_type": "hash_ALL",
+        "key": "#hash#$hj",
+        "key_length": "5",
+        "used_key_parts": ["b"],
+        "ref": ["test.t11.b"],
+        "r_loops": 1,
+        "rows": 1000,
+        "r_rows": 1000,
+        "r_table_time_ms": "REPLACED",
+        "r_other_time_ms": "REPLACED",
+        "filtered": 70.3125,
+        "r_filtered": 70,
+        "attached_condition": "t10.a < 700"
+      },
+      "buffer_type": "flat",
+      "buffer_size": "3Kb",
+      "join_type": "BNLH",
+      "attached_condition": "t10.b = t11.b",
+      "r_loops": 100,
+      "r_filtered": 100,
+      "r_effective_rows": 2.97
+    }
+  }
+}
+set join_cache_level=@tmp;
+drop table t10, t11;
diff --git a/mysql-test/main/analyze_format_json.test b/mysql-test/main/analyze_format_json.test
index 3f3324e9eec..84f44869afe 100644
--- a/mysql-test/main/analyze_format_json.test
+++ b/mysql-test/main/analyze_format_json.test
@@ -226,3 +226,45 @@ create table t2 as select * from t1;
 --source include/analyze-format.inc
 analyze format=json select a, (select t2.b from t2 where t2.a<t1.a order by t2.c limit 1) from t1 where t1.a<0;
 drop table t0,t1,t2;
+
+
+--echo #
+--echo # MDEV-30806: ANALYZE FORMAT=JSON: better support for BNL and BNL-H joins
+--echo #
+--source include/have_sequence.inc
+create table t10 (
+  a int,
+  b int
+);
+insert into t10 select seq, seq/3 from seq_0_to_999;
+
+create table t11 (
+  a int,
+  b int
+);
+insert into t11 select seq, seq/5 from seq_0_to_999;
+
+analyze table t10,t11 persistent for all;
+
+--source include/analyze-format.inc
+analyze format=json
+select * from t10, t11
+where
+ t10.a < 700 and
+ t11.a < 100
+ and t10.b=t11.b;
+
+set @tmp=@@join_cache_level, join_cache_level=6;
+
+--source include/analyze-format.inc
+analyze format=json
+select * from t10, t11
+where
+ t10.a < 700 and
+ t11.a < 100
+ and t10.b=t11.b;
+
+set join_cache_level=@tmp;
+drop table t10, t11;
+
+
diff --git a/mysql-test/main/analyze_stmt_orderby.result b/mysql-test/main/analyze_stmt_orderby.result
index 11736c47a49..d6aeeafeb73 100644
--- a/mysql-test/main/analyze_stmt_orderby.result
+++ b/mysql-test/main/analyze_stmt_orderby.result
@@ -441,7 +441,9 @@ ANALYZE
           "buffer_size": "65",
           "join_type": "BNL",
           "attached_condition": "t3.a = t0.a",
-          "r_filtered": 10
+          "r_loops": 10,
+          "r_filtered": 10,
+          "r_effective_rows": 10
         }
       }
     }
@@ -516,7 +518,9 @@ ANALYZE
               "buffer_size": "119",
               "join_type": "BNL",
               "attached_condition": "t5.a = t6.a",
-              "r_filtered": 21.42857143
+              "r_loops": 4,
+              "r_filtered": 21.42857143,
+              "r_effective_rows": 7
             }
           }
         }
diff --git a/mysql-test/main/except.result b/mysql-test/main/except.result
index 72d2a312bd2..bf92ceaafea 100644
--- a/mysql-test/main/except.result
+++ b/mysql-test/main/except.result
@@ -334,7 +334,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "119",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 2,
+              "r_filtered": 100,
+              "r_effective_rows": 2
             }
           }
         },
@@ -370,7 +372,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "119",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 2,
+              "r_filtered": 100,
+              "r_effective_rows": 2
             }
           }
         }
@@ -435,7 +439,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "119",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 2,
+                    "r_filtered": 100,
+                    "r_effective_rows": 2
                   }
                 }
               },
@@ -471,7 +477,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "119",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 2,
+                    "r_filtered": 100,
+                    "r_effective_rows": 2
                   }
                 }
               }
diff --git a/mysql-test/main/except_all.result b/mysql-test/main/except_all.result
index befd7e0f15a..6224be8021a 100644
--- a/mysql-test/main/except_all.result
+++ b/mysql-test/main/except_all.result
@@ -453,7 +453,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "119",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 3,
+              "r_filtered": 100,
+              "r_effective_rows": 3
             }
           }
         },
@@ -489,7 +491,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "119",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 2,
+              "r_filtered": 100,
+              "r_effective_rows": 3
             }
           }
         }
@@ -553,7 +557,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "119",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 3,
+                    "r_filtered": 100,
+                    "r_effective_rows": 3
                   }
                 }
               },
@@ -589,7 +595,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "119",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 2,
+                    "r_filtered": 100,
+                    "r_effective_rows": 3
                   }
                 }
               }
diff --git a/mysql-test/main/explain_json.result b/mysql-test/main/explain_json.result
index e93564132b3..3c3ee55e59e 100644
--- a/mysql-test/main/explain_json.result
+++ b/mysql-test/main/explain_json.result
@@ -1544,7 +1544,9 @@ ANALYZE
       "buffer_size": "400",
       "join_type": "BKA",
       "mrr_type": "Rowid-ordered scan",
-      "r_filtered": 100
+      "r_loops": 10,
+      "r_filtered": 100,
+      "r_effective_rows": 1
     }
   }
 }
diff --git a/mysql-test/main/intersect.result b/mysql-test/main/intersect.result
index 3a194b60008..149e67850e0 100644
--- a/mysql-test/main/intersect.result
+++ b/mysql-test/main/intersect.result
@@ -395,7 +395,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "256Kb",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 3,
+              "r_filtered": 100,
+              "r_effective_rows": 3
             }
           }
         }
@@ -478,7 +480,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "256Kb",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 3,
+                    "r_filtered": 100,
+                    "r_effective_rows": 3
                   }
                 }
               }
diff --git a/mysql-test/main/intersect_all.result b/mysql-test/main/intersect_all.result
index 96bfb9ca1fb..d046a5ea881 100644
--- a/mysql-test/main/intersect_all.result
+++ b/mysql-test/main/intersect_all.result
@@ -426,7 +426,9 @@ ANALYZE
               "buffer_type": "flat",
               "buffer_size": "65",
               "join_type": "BNL",
-              "r_filtered": 100
+              "r_loops": 5,
+              "r_filtered": 100,
+              "r_effective_rows": 7
             }
           }
         }
@@ -509,7 +511,9 @@ ANALYZE
                     "buffer_type": "flat",
                     "buffer_size": "65",
                     "join_type": "BNL",
-                    "r_filtered": 100
+                    "r_loops": 5,
+                    "r_filtered": 100,
+                    "r_effective_rows": 7
                   }
                 }
               }
diff --git a/mysql-test/main/rowid_filter_innodb.result b/mysql-test/main/rowid_filter_innodb.result
index 3e673afbc99..113d4d0cb22 100644
--- a/mysql-test/main/rowid_filter_innodb.result
+++ b/mysql-test/main/rowid_filter_innodb.result
@@ -3685,7 +3685,9 @@ ANALYZE
       "join_type": "BKA",
       "mrr_type": "Rowid-ordered scan",
       "attached_condition": "a.atp = 1",
-      "r_filtered": 100
+      "r_loops": 3,
+      "r_filtered": 100,
+      "r_effective_rows": 1
     },
     "block-nl-join": {
       "table": {
@@ -3709,7 +3711,9 @@ ANALYZE
       "join_type": "BKA",
       "mrr_type": "Rowid-ordered scan",
       "attached_condition": "fi.fh in (6311439873746261694,-397087483897438286,8518228073041491534,-5420422472375069774)",
-      "r_filtered": 40
+      "r_loops": 3,
+      "r_filtered": 40,
+      "r_effective_rows": 26.66666667
     }
   }
 }
diff --git a/sql/sql_analyze_stmt.h b/sql/sql_analyze_stmt.h
index 968b8d38295..fdbd5955f33 100644
--- a/sql/sql_analyze_stmt.h
+++ b/sql/sql_analyze_stmt.h
@@ -158,6 +158,25 @@ public:
   if (unlikely((tracker)->timed)) \
   { (tracker)->stop_tracking(thd); }
 
+
+/*
+  Just a counter to increment one value. Wrapped in a class to be uniform
+  with other counters used by ANALYZE.
+*/
+
+class Counter_tracker
+{
+public:
+  Counter_tracker() : r_scans(0) {}
+  ha_rows r_scans;
+
+  inline void on_scan_init() { r_scans++; }
+
+  bool has_scans() const { return (r_scans != 0); }
+  ha_rows get_loops() const { return r_scans; }
+};
+
+
 /*
   A class for collecting read statistics.
   
@@ -168,20 +187,16 @@ public:
    It can be used to track reading from files, buffers, etc).
 */
 
-class Table_access_tracker 
+class Table_access_tracker
 {
 public:
-  Table_access_tracker() :
-    r_scans(0), r_rows(0), /*r_rows_after_table_cond(0),*/
-    r_rows_after_where(0)
+  Table_access_tracker() : r_scans(0), r_rows(0), r_rows_after_where(0)
   {}
 
-  ha_rows r_scans; /* How many scans were ran on this join_tab */
+  ha_rows r_scans; /* how many scans were ran on this join_tab */
   ha_rows r_rows; /* How many rows we've got after that */
   ha_rows r_rows_after_where; /* Rows after applying attached part of WHERE */
 
-  bool has_scans() const { return (r_scans != 0); }
-  ha_rows get_loops() const { return r_scans; }
   double get_avg_rows() const
   {
     return r_scans
@@ -200,6 +215,9 @@ public:
   inline void on_scan_init() { r_scans++; }
   inline void on_record_read() { r_rows++; }
   inline void on_record_after_where() { r_rows_after_where++; }
+
+  bool has_scans() const { return (r_scans != 0); }
+  ha_rows get_loops() const { return r_scans; }
 };
 
 
diff --git a/sql/sql_explain.cc b/sql/sql_explain.cc
index 480a1259ba8..caec818d130 100644
--- a/sql/sql_explain.cc
+++ b/sql/sql_explain.cc
@@ -1891,12 +1891,29 @@ void Explain_table_access::print_explain_json(Explain_query *query,
 
     if (is_analyze)
     {
-      //writer->add_member("r_loops").add_ll(jbuf_tracker.get_loops());
+      writer->add_member("r_loops").add_ll(jbuf_loops_tracker.get_loops());
+
       writer->add_member("r_filtered");
       if (jbuf_tracker.has_scans())
         writer->add_double(jbuf_tracker.get_filtered_after_where()*100.0);
       else
         writer->add_null();
+      /*
+        effective_rows is average number of matches we got for an incoming
+        row. The row is stored in the join buffer and then is read
+        from there, possibly multiple times. We can't count this number
+        directly. Infer it as:
+         total_number_of_row_combinations_considered / r_loops.
+      */
+      writer->add_member("r_effective_rows");
+      if (jbuf_loops_tracker.has_scans())
+      {
+        double loops= (double)jbuf_loops_tracker.get_loops();
+        double row_combinations= (double)jbuf_tracker.r_rows;
+        writer->add_double(row_combinations / loops);
+      }
+      else
+        writer->add_null();
     }
   }
 
diff --git a/sql/sql_explain.h b/sql/sql_explain.h
index 31143ca9f77..746e1db1abd 100644
--- a/sql/sql_explain.h
+++ b/sql/sql_explain.h
@@ -842,8 +842,12 @@ public:
   Exec_time_tracker op_tracker;
   Gap_time_tracker extra_time_tracker;
 
+  /* When using join buffer: Track the reads from join buffer */
   Table_access_tracker jbuf_tracker;
   
+  /* When using join buffer: Track the number of incoming record combinations */
+  Counter_tracker jbuf_loops_tracker;
+
   Explain_rowid_filter *rowid_filter;
 
   int print_explain(select_result_sink *output, uint8 explain_flags, 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 14766302298..2889d757e20 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -21231,6 +21231,8 @@ sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
     /* The user has aborted the execution of the query */
     DBUG_RETURN(NESTED_LOOP_KILLED);
   }
+  join_tab->jbuf_loops_tracker->on_scan_init();
+
   if (!test_if_use_dynamic_range_scan(join_tab))
   {
     if (!cache->put_record())
@@ -27393,6 +27395,7 @@ bool JOIN_TAB::save_explain_data(Explain_table_access *eta,
   // psergey-todo: data for filtering!
   tracker= &eta->tracker;
   jbuf_tracker= &eta->jbuf_tracker;
+  jbuf_loops_tracker= &eta->jbuf_loops_tracker;
 
   /* Enable the table access time tracker only for "ANALYZE stmt" */
   if (thd->lex->analyze_stmt)
diff --git a/sql/sql_select.h b/sql/sql_select.h
index 4ff95b31f3f..178573413af 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -309,6 +309,7 @@ typedef struct st_join_table {
   Table_access_tracker *tracker;
 
   Table_access_tracker *jbuf_tracker;
+  Counter_tracker  *jbuf_loops_tracker;
   /* 
     Bitmap of TAB_INFO_* bits that encodes special line for EXPLAIN 'Extra'
     column, or 0 if there is no info.