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/merge.result

@@ -2024,6 +2024,8 @@ 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
 NULL	test	tm1	BASE TABLE	NULL	NULL	NULL	#	#	#	#	#	#	#	#	#	#	NULL	#	#	Unable to open underlying table which is differently defined or of non-MyISAM ty
+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;

mysql-test/r/show_check.result

@@ -660,6 +660,8 @@ 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;
@@ -1196,7 +1198,7 @@ set names koi8r;
 DROP DATABASE IF EXISTS mysqltest1;
 CREATE DATABASE mysqltest1;
 use mysqltest1;
-CREATE TABLE t1(1 INT);
+CREATE TABLE t1(�������1 INT);
 
 ---> Dumping mysqltest1 to outfile1
 
@@ -1208,7 +1210,7 @@ DROP DATABASE mysqltest1;
 SHOW CREATE TABLE mysqltest1.t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `1` int(11) DEFAULT NULL
+  `�������1` int(11) DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 DROP DATABASE mysqltest1;
 use test;
@@ -1415,14 +1417,14 @@ DROP PROCEDURE IF EXISTS p1;
 DROP FUNCTION IF EXISTS f1;
 DROP TABLE IF EXISTS t1;
 DROP EVENT IF EXISTS ev1;
-CREATE VIEW v1 AS SELECT '' AS test;
-CREATE PROCEDURE p1() SELECT '' AS test;
-CREATE FUNCTION f1() RETURNS CHAR(10) RETURN '';
+CREATE VIEW v1 AS SELECT '����' AS test;
+CREATE PROCEDURE p1() SELECT '����' AS test;
+CREATE FUNCTION f1() RETURNS CHAR(10) RETURN '����';
 CREATE TABLE t1(c1 CHAR(10));
 CREATE TRIGGER t1_bi BEFORE INSERT ON t1
 FOR EACH ROW
-SET NEW.c1 = '';
-CREATE EVENT ev1 ON SCHEDULE AT '2030-01-01 00:00:00' DO SELECT '' AS test;
+SET NEW.c1 = '����';
+CREATE EVENT ev1 ON SCHEDULE AT '2030-01-01 00:00:00' DO SELECT '����' AS test;
 set names utf8;
 SHOW CREATE VIEW v1;
 View	Create View	character_set_client	collation_connection

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 define
+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;

mysql-test/suite/federated/federated_bug_35333.result

+#
+# 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.
+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;

mysql-test/suite/federated/federated_bug_35333.test

+--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

sql/sql_show.cc

@@ -3636,28 +3636,28 @@ 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");
 
   restore_record(table, s->default_values);
   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->main_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);
@@ -3746,9 +3746,14 @@ static int get_schema_tables_record(THD *thd, TABLE_LIST *tables,
     if (share->comment.str)
       table->field[20]->store(share->comment.str, share->comment.length, cs);
 
-    if(file)
+    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:
@@ -3826,6 +3831,26 @@ 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->main_da.message() : "";
+    table->field[20]->store(error, strlen(error), cs);
+
+    if (thd->is_error())
+    {
+      push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                   thd->main_da.sql_errno(), thd->main_da.message());
+      thd->clear_error();
+    }
+  }
+  
   DBUG_RETURN(schema_table_store_record(thd, table));
 }