Bug#35333, "If Federated table can't connect to remote host, can't retrieve

metadata"

Improved error handling such that queries against Information_Schema.Tables won't
fail if a federated table can't make a remote connection.

mysql-test/r/lock_multi.result:
  Updated with warnings that were previously masked.
mysql-test/r/mdl_sync.result:
  Updated with warnings that were previously masked.
mysql-test/r/merge.result:
  Updated with warnings that were previously masked.
mysql-test/r/show_check.result:
  Updated with warnings that were previously masked.
mysql-test/r/view.result:
  Updated with warnings that were previously masked.
mysql-test/suite/federated/federated_bug_35333.result:
  New test results for bug#35333
mysql-test/suite/federated/federated_bug_35333.test:
  New test or bug#35333
sql/sql_show.cc:
  If get_schema_tables_record() encounters an error, push a warning,
  set the TABLE COMMENT column with the error text, and clear the
  error so that the operation can continue.

8 files changed, 205 insertions, 8 deletions

diff --git a/mysql-test/r/lock_multi.result b/mysql-test/r/lock_multi.result
index 99e1f54e762..1a8ef2deefd 100644
--- a/mysql-test/r/lock_multi.result
+++ b/mysql-test/r/lock_multi.result
@@ -430,6 +430,8 @@ SELECT table_name, table_comment FROM information_schema.tables
 WHERE table_schema= 'test' AND table_name= 't1';
 table_name	table_comment
 t1	Lock wait timeout exceeded; try restarting transaction
+Warnings:
+Warning	1205	Lock wait timeout exceeded; try restarting transaction
 # Connection default
 UNLOCK TABLES;
 # Connection con3
diff --git a/mysql-test/r/mdl_sync.result b/mysql-test/r/mdl_sync.result
index 594cf433692..b2e71faf741 100644
--- a/mysql-test/r/mdl_sync.result
+++ b/mysql-test/r/mdl_sync.result
@@ -2322,6 +2322,8 @@ select table_name, table_type, auto_increment, table_comment
 from information_schema.tables where table_schema='test' and table_name='t2';
 table_name	table_type	auto_increment	table_comment
 t2	BASE TABLE	NULL	Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
+Warnings:
+Warning	1684	Table 'test'.'t2' was skipped since its definition is being modified by concurrent DDL statement
 # Switching to connection 'default'.
 unlock tables;
 # Switching to connection 'con46044'.
diff --git a/mysql-test/r/merge.result b/mysql-test/r/merge.result
index ace834a26c2..f668761cb16 100644
--- a/mysql-test/r/merge.result
+++ b/mysql-test/r/merge.result
@@ -2084,6 +2084,8 @@ SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE
 TABLE_SCHEMA = 'test' and TABLE_NAME='tm1';
 TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	TABLE_TYPE	ENGINE	VERSION	ROW_FORMAT	TABLE_ROWS	AVG_ROW_LENGTH	DATA_LENGTH	MAX_DATA_LENGTH	INDEX_LENGTH	DATA_FREE	AUTO_INCREMENT	CREATE_TIME	UPDATE_TIME	CHECK_TIME	TABLE_COLLATION	CHECKSUM	CREATE_OPTIONS	TABLE_COMMENT
 def	test	tm1	BASE TABLE	NULL	NULL	NULL	#	#	#	#	#	#	#	#	#	#	NULL	#	#	Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
+Warnings:
+Warning	1168	Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exist
 DROP TABLE tm1;
 CREATE TABLE t1(C1 INT, C2 INT, KEY C1(C1), KEY C2(C2)) ENGINE=MYISAM;
 CREATE TABLE t2(C1 INT, C2 INT, KEY C1(C1), KEY C2(C2)) ENGINE=MYISAM;
diff --git a/mysql-test/r/show_check.result b/mysql-test/r/show_check.result
index 5e41e6b29c6..d42cb680112 100644
--- a/mysql-test/r/show_check.result
+++ b/mysql-test/r/show_check.result
@@ -663,6 +663,8 @@ flush tables;
 SHOW TABLE STATUS like 't1';
 Name	Engine	Version	Row_format	Rows	Avg_row_length	Data_length	Max_data_length	Index_length	Data_free	Auto_increment	Create_time	Update_time	Check_time	Collation	Checksum	Create_options	Comment
 t1	NULL	NULL	NULL	NULL	#	#	#	#	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Incorrect information in file: './test/t1.frm'
+Warnings:
+Warning	1033	Incorrect information in file: './test/t1.frm'
 show create table t1;
 ERROR HY000: Incorrect information in file: './test/t1.frm'
 drop table if exists t1;
diff --git a/mysql-test/r/view.result b/mysql-test/r/view.result
index 777ac9c258f..8d39b4e596b 100644
--- a/mysql-test/r/view.result
+++ b/mysql-test/r/view.result
@@ -840,6 +840,8 @@ show table status;
 Name	Engine	Version	Row_format	Rows	Avg_row_length	Data_length	Max_data_length	Index_length	Data_free	Auto_increment	Create_time	Update_time	Check_time	Collation	Checksum	Create_options	Comment
 t1	MyISAM	10	Fixed	0	0	0	#	1024	0	NULL	#	#	NULL	latin1_swedish_ci	NULL		
 v1	NULL	NULL	NULL	NULL	NULL	NULL	#	NULL	NULL	NULL	#	#	NULL	NULL	NULL	NULL	View 'test.v1' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+Warnings:
+Warning	1356	View 'test.v1' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
 drop view v1;
 drop table t1;
 create view v1 as select 99999999999999999999999999999999999999999999999999999 as col1;
diff --git a/mysql-test/suite/federated/federated_bug_35333.result b/mysql-test/suite/federated/federated_bug_35333.result
new file mode 100644
index 00000000000..ca7aa960b73
--- /dev/null
+++ b/mysql-test/suite/federated/federated_bug_35333.result
@@ -0,0 +1,67 @@
+#
+# Bug 35333 "If a Federated table can't connect to the remote hose, can't retrieve metadata"
+#
+# Queries such as SHOW TABLE STATUS and SELECT * FROM INFORMATION_SCHEMA.TABLES fail
+# when encountering a federated table that cannot connect to its remote table.
+#
+# The fix is to store the error text in the TABLE COMMENTS column of I_S.TABLES, clear
+# the remote connection error and push a warning instead. This allows the SELECT operation
+# to complete while still indicating a problem. This fix applies to any non-fatal system
+# error that occurs during a query against I_S.TABLES.de
+CREATE DATABASE federated;
+CREATE DATABASE federated;
+CREATE DATABASE IF NOT EXISTS realdb;
+DROP TABLE IF EXISTS realdb.t0;
+DROP TABLE IF EXISTS federated.t0;
+#
+# Create the base table to be referenced
+#
+CREATE TABLE realdb.t0 (a text, b text) ENGINE=MYISAM;
+#
+# Create a federated table with a bogus port number
+#
+CREATE TABLE federated.t0 (a text, b text) ENGINE=FEDERATED
+CONNECTION='mysql://root@127.0.0.1:63333/realdb/t0';
+#
+# Trigger a federated system error during a INFORMATION_SCHEMA.TABLES query
+#
+SELECT TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE, ENGINE, ROW_FORMAT, TABLE_ROWS, DATA_LENGTH, TABLE_COMMENT
+FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'realdb' or TABLE_SCHEMA = 'federated';
+TABLE_SCHEMA	TABLE_NAME	TABLE_TYPE	ENGINE	ROW_FORMAT	TABLE_ROWS	DATA_LENGTH	TABLE_COMMENT
+federated	t0	BASE TABLE	FEDERATED		NULL	0	Unable to connect to foreign data source: Can't connect to MySQL server on '127.0.0.1' (socket errno)
+realdb	t0	BASE TABLE	MyISAM	Dynamic	0	0	
+Warnings:
+Warning	1429	Unable to connect to foreign data source: Can't connect to MySQL server on '127.0.0.1' (socket errno)
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1429	Unable to connect to foreign data source: Can't connect to MySQL server on '127.0.0.1' (socket errno)
+#
+# Create a MyISAM table then corrupt the file
+#
+USE realdb;
+CREATE TABLE t1 (c1 int) ENGINE=MYISAM;
+#
+# Corrupt the MyISAM table by deleting the base file
+#
+#
+# Trigger a MyISAM system error during an INFORMATION_SCHEMA.TABLES query
+#
+SELECT TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE, ENGINE, ROW_FORMAT, TABLE_ROWS, DATA_LENGTH, TABLE_COMMENT
+FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't1';
+TABLE_SCHEMA	TABLE_NAME	TABLE_TYPE	ENGINE	ROW_FORMAT	TABLE_ROWS	DATA_LENGTH	TABLE_COMMENT
+realdb	t1	BASE TABLE	NULL	NULL	NULL	NULL	Can't find file: 't1' (errno: 2)
+Warnings:
+Warning	1017	Can't find file: 't1' (errno: 2)
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1017	Can't find file: 't1' (errno: 2)
+#
+# Cleanup
+#
+DROP TABLE IF EXISTS realdb.t0;
+DROP TABLE IF EXISTS federated.t0;
+DROP DATABASE realdb;
+DROP TABLE IF EXISTS federated.t1;
+DROP DATABASE federated;
+DROP TABLE IF EXISTS federated.t1;
+DROP DATABASE federated;
diff --git a/mysql-test/suite/federated/federated_bug_35333.test b/mysql-test/suite/federated/federated_bug_35333.test
new file mode 100644
index 00000000000..58c217d24f2
--- /dev/null
+++ b/mysql-test/suite/federated/federated_bug_35333.test
@@ -0,0 +1,74 @@
+--echo #
+--echo # Bug 35333 "If a Federated table can't connect to the remote hose, can't retrieve metadata"
+--echo #
+--echo # Queries such as SHOW TABLE STATUS and SELECT * FROM INFORMATION_SCHEMA.TABLES fail
+--echo # when encountering a federated table that cannot connect to its remote table.
+--echo #
+--echo # The fix is to store the error text in the TABLE COMMENTS column of I_S.TABLES, clear
+--echo # the remote connection error and push a warning instead. This allows the SELECT operation
+--echo # to complete while still indicating a problem. This fix applies to any non-fatal system
+--echo # error that occurs during a query against I_S.TABLES.de
+
+--source federated.inc
+
+--disable_warnings
+CREATE DATABASE IF NOT EXISTS realdb;
+# Federated database exists
+DROP TABLE IF EXISTS realdb.t0;
+DROP TABLE IF EXISTS federated.t0;
+--enable_warnings
+
+--echo #
+--echo # Create the base table to be referenced
+--echo #
+CREATE TABLE realdb.t0 (a text, b text) ENGINE=MYISAM;
+
+--echo #
+--echo # Create a federated table with a bogus port number
+--echo #
+CREATE TABLE federated.t0 (a text, b text) ENGINE=FEDERATED
+    CONNECTION='mysql://root@127.0.0.1:63333/realdb/t0';
+
+#--warning ER_CONNECT_TO_FOREIGN_DATA_SOURCE
+
+--echo #
+--echo # Trigger a federated system error during a INFORMATION_SCHEMA.TABLES query
+--echo #
+# Remove O/S-specific socket error
+--replace_regex /\(.*\)/(socket errno)/
+SELECT TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE, ENGINE, ROW_FORMAT, TABLE_ROWS, DATA_LENGTH, TABLE_COMMENT
+       FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'realdb' or TABLE_SCHEMA = 'federated';
+
+# Remove O/S-specific socket error
+--replace_regex /\(.*\)/(socket errno)/
+SHOW WARNINGS;
+
+--echo #
+--echo # Create a MyISAM table then corrupt the file
+--echo #
+USE realdb;
+CREATE TABLE t1 (c1 int) ENGINE=MYISAM;
+--echo #
+--echo # Corrupt the MyISAM table by deleting the base file
+--echo #
+let $MYSQLD_DATADIR= `SELECT @@datadir`;
+--remove_file $MYSQLD_DATADIR/realdb/t1.MYD
+--remove_file $MYSQLD_DATADIR/realdb/t1.MYI
+
+--echo #
+--echo # Trigger a MyISAM system error during an INFORMATION_SCHEMA.TABLES query
+--echo #
+SELECT TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE, ENGINE, ROW_FORMAT, TABLE_ROWS, DATA_LENGTH, TABLE_COMMENT
+       FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't1';
+
+SHOW WARNINGS;
+--echo #
+--echo # Cleanup
+--echo #
+--disable_warnings
+DROP TABLE IF EXISTS realdb.t0;
+DROP TABLE IF EXISTS federated.t0;
+DROP DATABASE realdb;
+--enable_warnings
+
+--source federated_cleanup.inc
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index f8853611b39..2c71fe5dd48 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -3781,6 +3781,7 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
 {
   const char *tmp_buff;
   MYSQL_TIME time;
+  int info_error= 0;
   CHARSET_INFO *cs= system_charset_info;
   DBUG_ENTER("get_schema_tables_record");
 
@@ -3788,22 +3789,21 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
   table->field[0]->store(STRING_WITH_LEN("def"), cs);
   table->field[1]->store(db_name->str, db_name->length, cs);
   table->field[2]->store(table_name->str, table_name->length, cs);
+
   if (res)
   {
-    /*
-      there was errors during opening tables
-    */
-    const char *error= thd->is_error() ? thd->stmt_da->message() : "";
+    /* There was a table open error, so set the table type and return */
     if (tables->view)
       table->field[3]->store(STRING_WITH_LEN("VIEW"), cs);
     else if (tables->schema_table)
       table->field[3]->store(STRING_WITH_LEN("SYSTEM VIEW"), cs);
     else
       table->field[3]->store(STRING_WITH_LEN("BASE TABLE"), cs);
-    table->field[20]->store(error, strlen(error), cs);
-    thd->clear_error();
+
+    goto err;
   }
-  else if (tables->view)
+
+  if (tables->view)
   {
     table->field[3]->store(STRING_WITH_LEN("VIEW"), cs);
     table->field[20]->store(STRING_WITH_LEN("VIEW"), cs);
@@ -3818,6 +3818,7 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
 #ifdef WITH_PARTITION_STORAGE_ENGINE
     bool is_partitioned= FALSE;
 #endif
+
     if (share->tmp_table == SYSTEM_TMP_TABLE)
       table->field[3]->store(STRING_WITH_LEN("SYSTEM VIEW"), cs);
     else if (share->tmp_table)
@@ -3831,6 +3832,9 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
         continue;
       table->field[i]->set_notnull();
     }
+
+    /* Collect table info from the table share */
+
 #ifdef WITH_PARTITION_STORAGE_ENGINE
     if (share->db_type() == partition_hton &&
         share->partition_info_str_len)
@@ -3839,62 +3843,82 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
       is_partitioned= TRUE;
     }
 #endif
+
     tmp_buff= (char *) ha_resolve_storage_engine_name(tmp_db_type);
     table->field[4]->store(tmp_buff, strlen(tmp_buff), cs);
     table->field[5]->store((longlong) share->frm_version, TRUE);
 
     ptr=option_buff;
+
     if (share->min_rows)
     {
       ptr=strmov(ptr," min_rows=");
       ptr=longlong10_to_str(share->min_rows,ptr,10);
     }
+
     if (share->max_rows)
     {
       ptr=strmov(ptr," max_rows=");
       ptr=longlong10_to_str(share->max_rows,ptr,10);
     }
+
     if (share->avg_row_length)
     {
       ptr=strmov(ptr," avg_row_length=");
       ptr=longlong10_to_str(share->avg_row_length,ptr,10);
     }
+
     if (share->db_create_options & HA_OPTION_PACK_KEYS)
       ptr=strmov(ptr," pack_keys=1");
+
     if (share->db_create_options & HA_OPTION_NO_PACK_KEYS)
       ptr=strmov(ptr," pack_keys=0");
+
     /* We use CHECKSUM, instead of TABLE_CHECKSUM, for backward compability */
     if (share->db_create_options & HA_OPTION_CHECKSUM)
       ptr=strmov(ptr," checksum=1");
+
     if (share->db_create_options & HA_OPTION_DELAY_KEY_WRITE)
       ptr=strmov(ptr," delay_key_write=1");
+
     if (share->row_type != ROW_TYPE_DEFAULT)
       ptr=strxmov(ptr, " row_format=", 
                   ha_row_type[(uint) share->row_type],
                   NullS);
+
     if (share->key_block_size)
     {
       ptr= strmov(ptr, " KEY_BLOCK_SIZE=");
       ptr= longlong10_to_str(share->key_block_size, ptr, 10);
     }
+
 #ifdef WITH_PARTITION_STORAGE_ENGINE
     if (is_partitioned)
       ptr= strmov(ptr, " partitioned");
 #endif
+
     table->field[19]->store(option_buff+1,
                             (ptr == option_buff ? 0 : 
                              (uint) (ptr-option_buff)-1), cs);
 
     tmp_buff= (share->table_charset ?
                share->table_charset->name : "default");
+
     table->field[17]->store(tmp_buff, strlen(tmp_buff), cs);
 
     if (share->comment.str)
       table->field[20]->store(share->comment.str, share->comment.length, cs);
 
+    /* Collect table info from the storage engine  */
+
     if(file)
     {
-      file->info(HA_STATUS_VARIABLE | HA_STATUS_TIME | HA_STATUS_AUTO);
+      /* If info() fails, then there's nothing else to do */
+      if ((info_error= file->info(HA_STATUS_VARIABLE |
+                                  HA_STATUS_TIME |
+                                  HA_STATUS_AUTO)) != 0)
+        goto err;
+
       enum row_type row_type = file->get_row_type();
       switch (row_type) {
       case ROW_TYPE_NOT_USED:
@@ -3923,7 +3947,9 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
         tmp_buff= "Paged";
         break;
       }
+
       table->field[6]->store(tmp_buff, strlen(tmp_buff), cs);
+
       if (!tables->schema_table)
       {
         table->field[7]->store((longlong) file->stats.records, TRUE);
@@ -3972,6 +3998,26 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
       }
     }
   }
+
+err:
+  if (res || info_error)
+  {
+    /*
+      If an error was encountered, push a warning, set the TABLE COMMENT
+      column with the error text, and clear the error so that the operation
+      can continue.
+    */
+    const char *error= thd->is_error() ? thd->stmt_da->message() : "";
+    table->field[20]->store(error, strlen(error), cs);
+
+    if (thd->is_error())
+    {
+      push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                   thd->stmt_da->sql_errno(), thd->stmt_da->message());
+      thd->clear_error();
+    }
+  }
+
   DBUG_RETURN(schema_table_store_record(thd, table));
 }