MDEV-26131 SEGV in ha_innobase::discard_or_import_tablespace

Import operation without .cfg file fails when there is mismatch of index
between metadata table and .ibd file. Moreover, MDEV-19022 shows
that InnoDB can end up with index tree where non-leaf page has only
one child page. So it is unsafe to find the secondary index root page.

This patch does the following when importing the table without .cfg file:

1) If the metadata contains more than one index then InnoDB stops
the import operation and report the user to drop all secondary
indexes before doing import operation.

2) When the metadata contain only clustered index then InnoDB finds the
index id by reading page 0 & page 3 instead of traversing the
whole tablespace.

mysql-test/suite/encryption/r/innodb_import.result

+#
+# MDEV-26131 SEGV in ha_innobase::discard_or_import_tablespace
+#
+CREATE TABLE t1(f1 int,f2 text)ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1, "InnoDB");
+CREATE TABLE t2 LIKE t1;
+ALTER TABLE t2 ADD KEY idx (f2(13));
+ALTER TABLE t2 DISCARD TABLESPACE;
+FLUSH TABLES t1 FOR EXPORT;
+UNLOCK TABLES;
+ALTER TABLE t2 IMPORT TABLESPACE;
+ERROR HY000: Internal error: Drop all secondary indexes before importing table test/t2 when .cfg file is missing.
+ALTER TABLE t2 DROP KEY idx;
+Warnings:
+Warning	1814	Tablespace has been discarded for table `t2`
+ALTER TABLE t2 IMPORT TABLESPACE;
+Warnings:
+Warning	1810	IO Read error: (2, No such file or directory) Error opening './test/t2.cfg', will attempt to import without schema verification
+SELECT * FROM t2;
+f1	f2
+1	InnoDB
+DROP TABLE t1, t2;

mysql-test/suite/encryption/t/innodb_import.combinations

+[page_compressed]
+innodb-compression-default=1
+[encryption]
+innodb-encrypt-tables=1
+[page_compressed_encryption]
+innodb-compression-default=1
+innodb-encrypt-tables=1

mysql-test/suite/encryption/t/innodb_import.test

+--source include/have_innodb.inc
+-- source include/have_example_key_management_plugin.inc
+--echo #
+--echo # MDEV-26131 SEGV in ha_innobase::discard_or_import_tablespace
+--echo #
+let $MYSQLD_DATADIR = `SELECT @@datadir`;
+CREATE TABLE t1(f1 int,f2 text)ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1, "InnoDB");
+CREATE TABLE t2 LIKE t1;
+ALTER TABLE t2 ADD KEY idx (f2(13));
+ALTER TABLE t2 DISCARD TABLESPACE;
+FLUSH TABLES t1 FOR EXPORT;
+--copy_file $MYSQLD_DATADIR/test/t1.ibd $MYSQLD_DATADIR/test/t2.ibd
+UNLOCK TABLES;
+--error ER_INTERNAL_ERROR
+ALTER TABLE t2 IMPORT TABLESPACE;
+
+ALTER TABLE t2 DROP KEY idx;
+ALTER TABLE t2 IMPORT TABLESPACE;
+SELECT * FROM t2;
+DROP TABLE t1, t2;

mysql-test/suite/innodb_gis/r/alter_spatial_index.result

@@ -252,6 +252,16 @@ UNLOCK TABLES;
 ALTER TABLE tab DISCARD TABLESPACE;
 SELECT c1,ST_Astext(c2),ST_Astext(c4) FROM tab;
 ERROR HY000: Tablespace has been discarded for table `tab`
+ERROR HY000: Internal error: Drop all secondary indexes before importing table test/tab when .cfg file is missing.
+Table	Create Table
+tab	CREATE TABLE `tab` (
+  `c1` int(11) NOT NULL,
+  `c2` point NOT NULL,
+  `c3` linestring NOT NULL,
+  `c4` polygon NOT NULL,
+  `c5` geometry NOT NULL,
+  PRIMARY KEY (`c2`(25))
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
 CHECK TABLE tab;
 Table	Op	Msg_type	Msg_text
 test.tab	check	status	OK
@@ -282,9 +292,6 @@ INSERT INTO tab SELECT * FROM tab1;
 ALTER TABLE tab DROP PRIMARY KEY;
 affected rows: 1
 info: Records: 1  Duplicates: 0  Warnings: 0
-ALTER TABLE tab DROP INDEX idx2;
-affected rows: 0
-info: Records: 0  Duplicates: 0  Warnings: 0
 SET STATEMENT sql_mode = 'NO_ENGINE_SUBSTITUTION' FOR
 CREATE TEMPORARY TABLE temp_tab AS SELECT * FROM tab where c1 = c2;
 INSERT INTO temp_tab SELECT * FROM tab;
@@ -322,18 +329,10 @@ tab	CREATE TABLE `tab` (
   `c2` point NOT NULL,
   `c3` linestring NOT NULL,
   `c4` polygon NOT NULL,
-  `c5` geometry NOT NULL,
-  SPATIAL KEY `idx3` (`c3`),
-  SPATIAL KEY `idx4` (`c4`) COMMENT 'testing spatial index on Polygon',
-  SPATIAL KEY `idx5` (`c5`) COMMENT 'testing spatial index on Geometry',
-  KEY `idx6` (`c4`(10)) USING BTREE
+  `c5` geometry NOT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 SHOW INDEX FROM tab;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
-tab	1	idx3	1	c3	A	#	32	NULL		SPATIAL		
-tab	1	idx4	1	c4	A	#	32	NULL		SPATIAL		testing spatial index on Polygon
-tab	1	idx5	1	c5	A	#	32	NULL		SPATIAL		testing spatial index on Geometry
-tab	1	idx6	1	c4	A	#	10	NULL		BTREE		
 DELETE FROM tab;
 ALTER TABLE tab ADD PRIMARY KEY(c2);
 affected rows: 0
@@ -354,20 +353,12 @@ tab	CREATE TABLE `tab` (
   `c5` geometry NOT NULL,
   PRIMARY KEY (`c2`(25)),
   UNIQUE KEY `const_1` (`c2`(25)),
-  SPATIAL KEY `idx3` (`c3`),
-  SPATIAL KEY `idx4` (`c4`) COMMENT 'testing spatial index on Polygon',
-  SPATIAL KEY `idx5` (`c5`) COMMENT 'testing spatial index on Geometry',
-  KEY `idx6` (`c4`(10)) USING BTREE,
   SPATIAL KEY `idx2` (`c2`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 SHOW INDEX FROM tab;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
 tab	0	PRIMARY	1	c2	A	#	25	NULL		BTREE		
 tab	0	const_1	1	c2	A	#	25	NULL		BTREE		
-tab	1	idx3	1	c3	A	#	32	NULL		SPATIAL		
-tab	1	idx4	1	c4	A	#	32	NULL		SPATIAL		testing spatial index on Polygon
-tab	1	idx5	1	c5	A	#	32	NULL		SPATIAL		testing spatial index on Geometry
-tab	1	idx6	1	c4	A	#	10	NULL		BTREE		
 tab	1	idx2	1	c2	A	#	32	NULL		SPATIAL		
 INSERT INTO tab(c1,c2,c3,c4,c5)
 VALUES(1,ST_GeomFromText('POINT(10 10)'),ST_GeomFromText('LINESTRING(5 5,20 20,30 30)'),
@@ -396,20 +387,12 @@ tab	CREATE TABLE `tab` (
   `c5` geometry NOT NULL,
   PRIMARY KEY (`c5`(10)),
   UNIQUE KEY `const_1` (`c5`(10)),
-  SPATIAL KEY `idx3` (`c3`),
-  SPATIAL KEY `idx4` (`c4`) COMMENT 'testing spatial index on Polygon',
-  SPATIAL KEY `idx5` (`c5`) COMMENT 'testing spatial index on Geometry',
-  KEY `idx6` (`c4`(10)) USING BTREE,
   SPATIAL KEY `idx2` (`c2`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 SHOW INDEX FROM tab;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
 tab	0	PRIMARY	1	c5	A	#	10	NULL		BTREE		
 tab	0	const_1	1	c5	A	#	10	NULL		BTREE		
-tab	1	idx3	1	c3	A	#	32	NULL		SPATIAL		
-tab	1	idx4	1	c4	A	#	32	NULL		SPATIAL		testing spatial index on Polygon
-tab	1	idx5	1	c5	A	#	32	NULL		SPATIAL		testing spatial index on Geometry
-tab	1	idx6	1	c4	A	#	10	NULL		BTREE		
 tab	1	idx2	1	c2	A	#	32	NULL		SPATIAL		
 INSERT INTO tab(c1,c2,c3,c4,c5)
 VALUES(1,ST_GeomFromText('POINT(10 10)'),ST_GeomFromText('LINESTRING(5 5,20 20,30 30)'),

mysql-test/suite/innodb_gis/t/alter_spatial_index.test

@@ -277,8 +277,17 @@ SELECT c1,ST_Astext(c2),ST_Astext(c4) FROM tab;
 
 --disable_query_log
 
+--error ER_INTERNAL_ERROR
 ALTER TABLE tab IMPORT TABLESPACE;
 
+ALTER TABLE tab DROP INDEX idx2;
+ALTER TABLE tab DROP INDEX idx3;
+ALTER TABLE tab DROP INDEX idx4;
+ALTER TABLE tab DROP INDEX idx5;
+ALTER TABLE tab DROP INDEX idx6;
+
+SHOW CREATE TABLE tab;
+ALTER TABLE tab IMPORT TABLESPACE;
 --enable_query_log
 
 CHECK TABLE tab;
@@ -308,7 +317,6 @@ INSERT INTO tab SELECT * FROM tab1;
 --enable_info
 ALTER TABLE tab DROP PRIMARY KEY;
 
-ALTER TABLE tab DROP INDEX idx2;
 --disable_info
 
 # Check spatial index on temp tables