MDEV-23433 Parent table discovery for children (REPAIR TABLE)

REPAIR TABLE on foreign table updates reference hints in referenced
tables if needed.

Better diagnostic error codes for CHECK TABLE.

mysql-test/main/foreign_key.result

@@ -475,18 +475,13 @@ set foreign_key_checks= 1;
 create or replace table t1 (id int primary key);
 drop table t1;
 create or replace table t1 (id int primary key);
-check tables t1, ch1;
+repair table ch1;
 Table	Op	Msg_type	Msg_text
-test.t1	check	status	OK
-test.ch1	check	Error	Referenced table test.t1 does not refer this table
-test.ch1	check	Note	Found 1 foreign keys
-test.ch1	check	status	Operation failed
-repair tables t1, ch1;
-Table	Op	Msg_type	Msg_text
-test.t1	repair	status	OK
+test.ch1	repair	Note	Found 1 foreign keys
+test.ch1	repair	Note	Updated 1 referenced shares
 test.ch1	repair	status	OK
 drop table t1;
-ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails
+ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (ch1_ibfk_1)
 drop table ch1;
 # Check drop database
 create or replace table t1 (id int primary key);

mysql-test/main/foreign_key.test

@@ -343,8 +343,8 @@ create or replace table t1 (id int primary key);
 # Since there is no reference hints in t1 now we cannot detect ER_ROW_IS_REFERENCED_2
 drop table t1;
 create or replace table t1 (id int primary key);
-check tables t1, ch1;
-repair tables t1, ch1;
+# Reference hints updated from repaired foreign tables
+repair table ch1;
 --error ER_ROW_IS_REFERENCED_2
 drop table t1;
 

sql/share/errmsg-utf8.txt

@@ -12268,3 +12268,29 @@ ER_SEQUENCE_TABLE_ORDER_BY
         eng "ORDER BY"
 ER_VARIABLE_IGNORED
         eng "The variable '%s' is ignored. It only exists for compatibility with old installations and will be removed in a future release"
+ER_FK_MDL_REFERENCED
+        eng "Could not metadata-lock referenced tables"
+ER_FK_NOT_EXISTS
+        eng "Foreign table `%s.%s` not exists"
+ER_FK_REF_NOT_EXISTS
+        eng "Referenced table `%s.%s` not exists"
+ER_FK_NOT_REFERS
+        eng "Foreign table `%s.%s` does not refer this table"
+ER_FK_REF_NOT_REFERS
+        eng "Referenced table `%s.%s` does not refer this table"
+ER_FK_NOT_MATCHES
+        eng "Foreign table `%s.%s` does not match foreign keys with referenced keys"
+ER_FK_REF_NOT_MATCHES
+        eng "Referenced table `%s.%s` does not match referenced keys with foreign keys"
+WARN_FK_FOUND
+        eng "Found %u foreign keys"
+WARN_FK_FOUND_REFERENCES
+        eng "Found %u referenced keys"
+WARN_FK_FOUND_SELFREFS
+        eng "Found %u self-references"
+WARN_FK_UPDATED_SHARES
+        eng "Updated %u referenced shares"
+ER_FK_WRONG_SELFREF
+        eng "Self-reference in foreign list `%s.%s` does not point to this table"
+ER_FK_UNEXPECTED_SELFREFS
+        eng "Found %u self-references in referenced list (must be 0)"

sql/sql_admin.cc

@@ -938,6 +938,13 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
         compl_result_code= result_code= HA_ADMIN_FAILED;
       }
     }
+    else if (operator_func == &handler::ha_repair)
+    {
+      if (table->table->s->fk_check_consistency(thd, true))
+      {
+        compl_result_code= result_code= HA_ADMIN_FAILED;
+      }
+    }
 
     if (result_code == HA_ADMIN_OK)
     {    

sql/sql_table.cc

@@ -9639,8 +9639,8 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
     if (thd->mdl_context.acquire_locks(&alter_ctx->fk_mdl_reqs,
                                        thd->variables.lock_wait_timeout))
     {
-      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, ER_UNKNOWN_ERROR,
-                          "Could not lock referenced tables");
+      push_warning(thd, Sql_condition::WARN_LEVEL_NOTE, ER_FK_MDL_REFERENCED,
+                   ER_THD(thd, ER_FK_MDL_REFERENCED));
       goto err;
     }
     /** Preacquire shares to get ER_NO_SUCH_TABLE before copy data */

sql/table.cc

@@ -10778,13 +10778,17 @@ KEY * FK_info::find_idx(KEY *key_info, uint keys, bool foreign_idx)
 }
 
 
-bool TABLE_SHARE::fk_check_consistency(THD *thd)
+bool TABLE_SHARE::fk_check_consistency(THD *thd, bool repair)
 {
   mbd::set<Table_name> warned;
   mbd::set<Table_name> warned_self;
   bool error= false;
   uint rk_self_refs= 0;
   uint fk_self_refs= 0;
+  mbd::set<FK_table_to_lock> fk_tables_to_lock;
+  MDL_request_list fk_mdl_reqs;
+  mbd::map<TABLE_SHARE *, FK_ref_backup> fk_ref_backup;
+
   for (FK_info &rk: referenced_keys)
   {
     if (rk.self_ref())
@@ -10799,10 +10803,7 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
     if (!sa.share)
     {
       if (!ha_table_exists(thd, &rk.foreign_db, &rk.foreign_table))
-      {
-        my_printf_error(ER_UNKNOWN_ERROR, "Foreign table %s.%s not exists",
-                        MYF(0), rk.foreign_db.str, rk.foreign_table.str);
-      }
+        my_error(ER_FK_NOT_EXISTS, MYF(0), rk.foreign_db.str, rk.foreign_table.str);
       return true;
     }
     List_iterator_fast<FK_info> fk_it(sa.share->foreign_keys);
@@ -10827,13 +10828,8 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
       if (!warned.insert(Table_name(rk.foreign_db, rk.foreign_table), &warn))
         return true;
       if (warn)
-      {
-        my_printf_error(ER_UNKNOWN_ERROR,
-                        found_table ?
-                          "Foreign table %s.%s does not match foreign keys with referenced keys" :
-                          "Foreign table %s.%s does not refer this table",
-                        MYF(0), sa.share->db.str, sa.share->table_name.str);
-      }
+        my_error(found_table ? ER_FK_NOT_MATCHES : ER_FK_NOT_REFERS,
+                 MYF(0), sa.share->db.str, sa.share->table_name.str);
       DBUG_ASSERT(warn || error);
       error= true;
     }
@@ -10845,8 +10841,8 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
   if (referenced_keys.elements)
   {
     push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
-                        ER_UNKNOWN_ERROR,
-                        "Found %u referenced keys",
+                        WARN_FK_FOUND_REFERENCES,
+                        ER_THD(thd, WARN_FK_FOUND_REFERENCES),
                         referenced_keys.elements);
   }
 
@@ -10860,17 +10856,54 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
         if (!warned_self.insert(Table_name(fk.foreign_db, fk.foreign_table), &warn))
           return true;
         if (warn)
-        {
-          my_printf_error(ER_UNKNOWN_ERROR,
-                          "Self-reference in foreign list %s.%s does not point to this table",
-                          MYF(0), fk.foreign_db, fk.foreign_table);
-        }
+          my_error(ER_FK_WRONG_SELFREF, MYF(0), fk.foreign_db, fk.foreign_table);
         DBUG_ASSERT(warn || error);
         error= true;
       }
       fk_self_refs++;
       continue;
     }
+    Table_name t(fk.ref_table(thd->mem_root));
+    if (!fk_tables_to_lock.insert(t))
+      return true;
+  }
+
+  if (!fk_tables_to_lock.empty())
+  {
+    for (const FK_table_to_lock &t: fk_tables_to_lock)
+    {
+      MDL_request *req= new (thd->mem_root) MDL_request;
+      if (!req)
+      {
+        my_error(ER_OUT_OF_RESOURCES, MYF(0));
+        return true;
+      }
+      MDL_REQUEST_INIT(req, MDL_key::TABLE, t.table.db.str, t.table.name.str,
+                       MDL_SHARED, MDL_STATEMENT);
+      fk_mdl_reqs.push_front(req);
+    }
+  }
+
+  if (thd->mdl_context.acquire_locks(&fk_mdl_reqs,
+                                     thd->variables.lock_wait_timeout))
+  {
+    // FIXME: error code
+    push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, ER_UNKNOWN_ERROR,
+                        "Could not metadata-lock referenced tables");
+    return true;
+  }
+
+  if (repair)
+  {
+    if (thd->mdl_context.upgrade_shared_locks(&fk_mdl_reqs, MDL_EXCLUSIVE,
+                                              thd->variables.lock_wait_timeout))
+      return true;
+  }
+
+  for (FK_info &fk: foreign_keys)
+  {
+    if (fk.self_ref())
+      continue;
     TABLE_LIST tl;
     tl.init_one_table(fk.ref_db_ptr(), &fk.referenced_table, NULL, TL_IGNORE);
     Share_acquire sa(thd, tl);
@@ -10878,8 +10911,7 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
     {
       if (!ha_table_exists(thd, fk.ref_db_ptr(), &fk.referenced_table))
       {
-        my_printf_error(ER_UNKNOWN_ERROR, "Referenced table %s.%s not exists",
-                        MYF(0), fk.ref_db().str, fk.referenced_table.str);
+        my_error(ER_FK_REF_NOT_EXISTS, MYF(0), fk.ref_db().str, fk.referenced_table.str);
       }
       return true;
     }
@@ -10901,46 +10933,113 @@ bool TABLE_SHARE::fk_check_consistency(THD *thd)
     }
     if (!rk)
     {
-      bool warn;
-      if (!warned.insert(Table_name(fk.foreign_db, fk.foreign_table), &warn))
-        return true;
-      if (warn)
+      if (repair)
+      {
+        // Similar to fk_handle_alter()
+        TABLE_SHARE *ref_share= sa.share;
+        if (ref_share->partitioned())
+        {
+          my_error(ER_FEATURE_NOT_SUPPORTED_WITH_PARTITIONING, MYF(0), "FOREIGN KEY");
+          return true;
+        }
+        FK_ref_backup *ref_bak;
+        FK_ref_backup fk_bak;
+        if (fk_bak.init(ref_share))
+          return true;
+        auto found= fk_ref_backup.find(ref_share);
+        if (found != fk_ref_backup.end())
+          ref_bak= &found->second;
+        else
+          ref_bak= fk_ref_backup.insert(ref_share, fk_bak);
+        if (!ref_bak)
+          return true;
+        FK_info *dst= fk.clone(&ref_share->mem_root);
+        if (!dst ||
+            ref_share->referenced_keys.push_back(dst, &ref_share->mem_root))
+        {
+          my_error(ER_OUT_OF_RESOURCES, MYF(0));
+          return true;
+        }
+      }
+      else
       {
-        my_printf_error(ER_UNKNOWN_ERROR,
-                        found_table ?
-                          "Referenced table %s.%s does not match referenced keys with foreign keys" :
-                          "Referenced table %s.%s does not refer this table", MYF(0),
-                        sa.share->db.str, sa.share->table_name.str);
+        bool warn;
+        if (!warned.insert(Table_name(fk.foreign_db, fk.foreign_table), &warn))
+          return true;
+        if (warn)
+        {
+          my_error(found_table ? ER_FK_REF_NOT_MATCHES : ER_FK_NOT_MATCHES, MYF(0),
+                   sa.share->db.str, sa.share->table_name.str);
+        }
+        DBUG_ASSERT(warn || error);
+        error= true;
       }
-      DBUG_ASSERT(warn || error);
-      error= true;
     }
   }
 
   if (foreign_keys.elements - fk_self_refs)
   {
     push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
-                        ER_UNKNOWN_ERROR,
-                        "Found %u foreign keys",
+                        WARN_FK_FOUND,
+                        ER_THD(thd, WARN_FK_FOUND),
                         foreign_keys.elements - fk_self_refs);
   }
 
   if (rk_self_refs)
   {
-    my_printf_error(ER_UNKNOWN_ERROR,
-                    "Found %u self-references in referenced list (must be 0)",
-                    MYF(0), rk_self_refs);
+    my_error(ER_FK_UNEXPECTED_SELFREFS, MYF(0), rk_self_refs);
     error= true;
   }
 
   if (fk_self_refs)
   {
     push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
-                        ER_UNKNOWN_ERROR,
-                        "Found %u self-references",
+                        WARN_FK_FOUND_SELFREFS,
+                        ER_THD(thd, WARN_FK_FOUND_SELFREFS),
                         fk_self_refs);
   }
 
+  /* Update EXTRA2_FOREIGN_KEY_INFO section in FRM files. */
+  if (repair)
+  {
+    const uint count= fk_ref_backup.size();
+    if (!error)
+    {
+      for (auto &key_val: fk_ref_backup)
+      {
+        FK_ref_backup *ref_bak= const_cast<FK_ref_backup *>(&key_val.second);
+        TABLE_SHARE *ref_share= ref_bak->share;
+        if (ref_share->fk_write_shadow_frm(thd))
+        {
+          error= true;
+          break;
+        }
+        ref_bak->install_shadow= true;
+      }
+    }
+    for (auto &key_val: fk_ref_backup)
+    {
+      FK_ref_backup *ref_bak= const_cast<FK_ref_backup *>(&key_val.second);
+      TABLE_SHARE *ref_share= ref_bak->share;
+      if (error)
+      {
+        if (ref_bak->install_shadow)
+          ref_share->fk_drop_shadow_frm();
+        ref_bak->rollback();
+      }
+      else
+      {
+        DBUG_ASSERT(ref_bak->install_shadow);
+        ref_share->fk_install_shadow_frm();
+      }
+    }
+    if (!error && count)
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                          WARN_FK_UPDATED_SHARES,
+                          ER_THD(thd, WARN_FK_UPDATED_SHARES), count);
+
+  }
+
   return error;
 }
 

sql/table.h

@@ -743,7 +743,7 @@ struct TABLE_SHARE
   FK_list referenced_keys;
   Field *find_field_by_name(const Lex_ident_column n) const;
   bool fk_handle_create(THD *thd, FK_create_vector &shares, FK_list *fk_add= NULL);
-  bool fk_check_consistency(THD *thd);
+  bool fk_check_consistency(THD *thd, bool repair= false);
   bool referenced_by_foreign_key() const
   {
     return !referenced_keys.is_empty();