MDEV-7318 RENAME INDEX

This patch adds support of RENAME INDEX operation to the ALTER TABLE
statement. Code which determines if ALTER TABLE can be done in-place
for "simple" storage engines like MyISAM, Heap and etc. was updated to
handle ALTER TABLE ... RENAME INDEX as an in-place operation. Support
for in-place ALTER TABLE ... RENAME INDEX for InnoDB was covered by
MDEV-13301.

Syntax changes
==============

A new type of <alter_specification> is added:

<rename index clause> ::= RENAME ( INDEX | KEY ) <oldname> TO <newname>

Where <oldname> and <newname> are identifiers for old name and new
name of the index.

Semantic changes
================

The result of "ALTER TABLE t1 RENAME INDEX a TO b" is a table which
contents and structure are identical to the old version of 't1' with
the only exception index 'a' being called 'b'.

Neither <oldname> nor <newname> can be "primary". The index being
renamed should exist and its new name should not be occupied
by another index on the same table.

Related to: WL#6555, MDEV-13301

mysql-test/main/alter_table.test

@@ -2273,6 +2273,186 @@ DROP VIEW v1;
 DROP TABLE t3,t1,t2;
 SET DEFAULT_STORAGE_ENGINE= @save_default_engine;
 
+--echo #
+--echo # MDEV-7318 RENAME INDEX
+--echo #
+
+--echo #
+--echo # 1) Tests for syntax and semantics of ALTER TABLE RENAME
+--echo #    KEY/INDEX result.
+--echo #
+--echo # 1.a) Both RENAME KEY and RENAME INDEX variants should be
+--echo #      allowed and produce expected results.
+create table t1 (pk int primary key, i int, j int, key a(i));
+alter table t1 rename key a to b;
+show create table t1;
+alter table t1 rename index b to c;
+show create table t1;
+
+--echo # 1.b) It should be impossible to rename index that doesn't
+--echo #      exists, dropped or added within the same ALTER TABLE.
+--error ER_KEY_DOES_NOT_EXITS
+alter table t1 rename key d to e;
+show create table t1;
+--error ER_KEY_DOES_NOT_EXITS
+alter table t1 drop key c, rename key c to d;
+show create table t1;
+--error ER_KEY_DOES_NOT_EXITS
+alter table t1 add key d(j), rename key d to e;
+show create table t1;
+
+--echo # 1.c) It should be impossible to rename index to a name
+--echo #      which is already used by another index, or is used
+--echo #      by index which is added within the same ALTER TABLE.
+alter table t1 add key d(j);
+--error ER_DUP_KEYNAME
+alter table t1 rename key c to d;
+show create table t1;
+alter table t1 drop key d;
+--error ER_DUP_KEYNAME
+alter table t1 add key d(j), rename key c to d;
+show create table t1;
+
+--echo # 1.d) It should be possible to rename index to a name
+--echo #      which belongs to index which is dropped within the
+--echo #      same ALTER TABLE.
+alter table t1 add key d(j);
+alter table t1 drop key c, rename key d to c;
+show create table t1;
+
+--echo # 1.e) We disallow renaming from/to PRIMARY as it might
+--echo #      lead to some other key becoming "primary" internally,
+--echo #      which will be interpreted as dropping/addition of
+--echo #      primary key.
+--error ER_PARSE_ERROR
+alter table t1 rename key primary to d;
+show create table t1;
+--echo # Even using 'funny' syntax.
+--error ER_WRONG_NAME_FOR_INDEX
+alter table t1 rename key `primary` to d;
+show create table t1;
+--error ER_PARSE_ERROR
+alter table t1 rename key c to primary;
+show create table t1;
+--error ER_WRONG_NAME_FOR_INDEX
+alter table t1 rename key c to `primary`;
+show create table t1;
+drop table t1;
+
+
+--echo #
+--echo # 2) More complex tests for semantics of ALTER TABLE.
+--echo #
+--echo # 2.a) Check that standalone RENAME KEY works as expected
+--echo #      for unique and non-unique indexes.
+create table t1 (a int, unique u(a), b int, key k(b));
+alter table t1 rename key u to uu;
+show create table t1;
+alter table t1 rename key k to kk;
+show create table t1;
+
+--echo # 2.b) Check how that this clause can be mixed with other
+--echo #      clauses which don't affect key or its columns.
+alter table t1 rename key kk to kkk, add column c int;
+show create table t1;
+alter table t1 rename key uu to uuu, add key c(c);
+show create table t1;
+alter table t1 rename key kkk to k, drop key uuu;
+show create table t1;
+alter table t1 rename key k to kk, rename to t2;
+show create table t2;
+drop table t2;
+
+
+--echo #
+--echo # 3) Test coverage for handling of RENAME INDEX clause in
+--echo #    various storage engines and using different ALTER
+--echo #    algorithm.
+--echo #
+--echo # 3.a) Test coverage for simple storage engines (MyISAM/Heap).
+create table t1 (i int, key k(i)) engine=myisam;
+insert into t1 values (1);
+create table t2 (i int, key k(i)) engine=memory;
+insert into t2 values (1);
+--echo # MyISAM and Heap should be able to handle key renaming in-place.
+alter table t1 algorithm=inplace, rename key k to kk;
+alter table t2 algorithm=inplace, rename key k to kk;
+show create table t1;
+show create table t2;
+--echo # So by default in-place algorithm should be chosen.
+--echo # (ALTER TABLE should report 0 rows affected).
+--enable_info
+alter table t1 rename key kk to kkk;
+alter table t2 rename key kk to kkk;
+--disable_info
+show create table t1;
+show create table t2;
+--echo # Copy algorithm should work as well.
+alter table t1 algorithm=copy, rename key kkk to kkkk;
+alter table t2 algorithm=copy, rename key kkk to kkkk;
+show create table t1;
+show create table t2;
+--echo # When renaming is combined with other in-place operation
+--echo # it still works as expected (i.e. works in-place).
+alter table t1 algorithm=inplace, rename key kkkk to k, alter column i set default 100;
+alter table t2 algorithm=inplace, rename key kkkk to k, alter column i set default 100;
+show create table t1;
+show create table t2;
+--echo # Combining with non-inplace operation results in the whole ALTER
+--echo # becoming non-inplace.
+--error ER_ALTER_OPERATION_NOT_SUPPORTED
+alter table t1 algorithm=inplace, rename key k to kk, add column j int;
+--error ER_ALTER_OPERATION_NOT_SUPPORTED
+alter table t2 algorithm=inplace, rename key k to kk, add column j int;
+drop table t1, t2;
+
+--echo # 3.b) Basic tests for InnoDB. More tests can be found in
+--echo #      innodb.innodb_rename_index*
+create table t1 (i int, key k(i)) engine=innodb;
+insert into t1 values (1);
+--echo # Basic rename, inplace algorithm should be chosen
+--enable_info
+alter table t1 algorithm=inplace, rename key k to kk;
+--disable_info
+show create table t1;
+--echo # copy algorithm should work as well.
+--enable_info
+alter table t1 algorithm=copy, rename key kk to kkk;
+--disable_info
+show create table t1;
+drop table t1;
+
+--echo #
+--echo # 4) Additional coverage for complex cases in which code
+--echo #    in ALTER TABLE comparing old and new table version
+--echo #    got confused.
+--echo #
+--echo # Once InnoDB starts to support in-place index renaming the result
+--echo # of below statements should stay the same. Information about
+--echo # indexes returned by SHOW CREATE TABLE (from .FRM) and by
+--echo # InnoDB (from InnoDB data-dictionary) should be consistent.
+--echo #
+create table t1 ( a int, b int, c int, d int,
+                  primary key (a), index i1 (b), index i2 (c) ) engine=innodb;
+alter table t1 add index i1 (d), rename index i1 to x;
+show create table t1;
+select i.name as k, f.name as c from information_schema.innodb_sys_tables as t,
+                                     information_schema.innodb_sys_indexes as i,
+                                     information_schema.innodb_sys_fields as f
+where t.name='test/t1' and t.table_id = i.table_id and i.index_id = f.index_id
+order by k, c;
+drop table t1;
+create table t1 (a int, b int, c int, d int,
+                 primary key (a), index i1 (b), index i2 (c)) engine=innodb;
+alter table t1 add index i1 (d), rename index i1 to i2, drop index i2;
+show create table t1;
+select i.name as k, f.name as c from information_schema.innodb_sys_tables as t,
+                                     information_schema.innodb_sys_indexes as i,
+                                     information_schema.innodb_sys_fields as f
+where t.name='test/t1' and t.table_id = i.table_id and i.index_id = f.index_id
+order by k, c;
+drop table t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

mysql-test/suite/innodb/r/innodb-alter-debug.result

@@ -98,3 +98,12 @@ disconnect con1;
 connection default;
 UNLOCK TABLES;
 DROP TABLE t1;
+#
+# MDEV-7318 RENAME INDEX
+#
+CREATE TABLE t (c1 INT, c2 INT, KEY i2 (c2)) ENGINE=INNODB;
+SET DEBUG_DBUG= '+d,ib_rename_index_fail1';
+ALTER TABLE t RENAME INDEX i2 to x, ALGORITHM=INPLACE;
+ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
+SET DEBUG_DBUG= '-d,ib_rename_index_fail1';
+DROP TABLE t;

mysql-test/suite/innodb/t/innodb-alter-debug.test

@@ -132,3 +132,15 @@ DROP TABLE t1;
 
 # Wait till all disconnects are completed
 --source include/wait_until_count_sessions.inc
+
+--echo #
+--echo # MDEV-7318 RENAME INDEX
+--echo #
+CREATE TABLE t (c1 INT, c2 INT, KEY i2 (c2)) ENGINE=INNODB;
+
+SET DEBUG_DBUG= '+d,ib_rename_index_fail1';
+-- error ER_LOCK_DEADLOCK
+ALTER TABLE t RENAME INDEX i2 to x, ALGORITHM=INPLACE;
+SET DEBUG_DBUG= '-d,ib_rename_index_fail1';
+
+DROP TABLE t;

sql/handler.cc

@@ -4585,7 +4585,8 @@ handler::check_if_supported_inplace_alter(TABLE *altered_table,
     ALTER_DROP_CHECK_CONSTRAINT |
     ALTER_PARTITIONED |
     ALTER_VIRTUAL_GCOL_EXPR |
-    ALTER_RENAME;
+    ALTER_RENAME |
+    ALTER_RENAME_INDEX;
 
   /* Is there at least one operation that requires copy algorithm? */
   if (ha_alter_info->handler_flags & ~inplace_offline_operations)

sql/sql_alter.cc

@@ -25,6 +25,7 @@ Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
   :drop_list(rhs.drop_list, mem_root),
   alter_list(rhs.alter_list, mem_root),
   key_list(rhs.key_list, mem_root),
+  alter_rename_key_list(rhs.alter_rename_key_list, mem_root),
   create_list(rhs.create_list, mem_root),
   check_constraint_list(rhs.check_constraint_list, mem_root),
   flags(rhs.flags), partition_flags(rhs.partition_flags),
@@ -46,6 +47,7 @@ Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
   list_copy_and_replace_each_value(drop_list, mem_root);
   list_copy_and_replace_each_value(alter_list, mem_root);
   list_copy_and_replace_each_value(key_list, mem_root);
+  list_copy_and_replace_each_value(alter_rename_key_list, mem_root);
   list_copy_and_replace_each_value(create_list, mem_root);
   /* partition_names are not deeply copied currently */
 }

sql/sql_alter.h

@@ -19,6 +19,7 @@
 
 class Alter_drop;
 class Alter_column;
+class Alter_rename_key;
 class Key;
 
 /**
@@ -87,6 +88,8 @@ class Alter_info
   List<Alter_column>            alter_list;
   // List of keys, used by both CREATE and ALTER TABLE.
   List<Key>                     key_list;
+  // List of keys to be renamed.
+  List<Alter_rename_key>        alter_rename_key_list;
   // List of columns, used by both CREATE and ALTER TABLE.
   List<Create_field>            create_list;
 
@@ -123,6 +126,7 @@ class Alter_info
     drop_list.empty();
     alter_list.empty();
     key_list.empty();
+    alter_rename_key_list.empty();
     create_list.empty();
     check_constraint_list.empty();
     flags= 0;

sql/sql_class.h

@@ -355,6 +355,21 @@ class Alter_column :public Sql_alloc {
 };
 
 
+class Alter_rename_key : public Sql_alloc
+{
+public:
+  LEX_CSTRING old_name;
+  LEX_CSTRING new_name;
+
+  Alter_rename_key(LEX_CSTRING old_name_arg, LEX_CSTRING new_name_arg)
+      : old_name(old_name_arg), new_name(new_name_arg) {}
+
+  Alter_rename_key *clone(MEM_ROOT *mem_root) const
+    { return new (mem_root) Alter_rename_key(*this); }
+
+};
+
+
 class Key :public Sql_alloc, public DDL_options {
 public:
   enum Keytype { PRIMARY, UNIQUE, MULTIPLE, FULLTEXT, SPATIAL, FOREIGN_KEY};

sql/sql_table.cc

@@ -6601,7 +6601,7 @@ static int compare_uint(const uint *s, const uint *t)
 
 enum class Compare_keys : uint32_t
 {
-  Equal,
+  Equal= 0,
   EqualButKeyPartLength,
   EqualButComment,
   NotEqual
@@ -7998,6 +7998,7 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
   List<Create_field> new_create_list;
   /* New key definitions are added here */
   List<Key> new_key_list;
+  List<Alter_rename_key> rename_key_list(alter_info->alter_rename_key_list);
   List_iterator<Alter_drop> drop_it(alter_info->drop_list);
   List_iterator<Create_field> def_it(alter_info->create_list);
   List_iterator<Alter_column> alter_it(alter_info->alter_list);
@@ -8446,6 +8447,39 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
       continue;
     }
 
+    /* If this index is to stay in the table check if it has to be renamed. */
+    List_iterator<Alter_rename_key> rename_key_it(rename_key_list);
+    Alter_rename_key *rename_key;
+
+    while ((rename_key= rename_key_it++))
+    {
+      if (!my_strcasecmp(system_charset_info, key_name, rename_key->old_name.str))
+      {
+        if (!my_strcasecmp(system_charset_info, key_name, primary_key_name))
+        {
+          my_error(ER_WRONG_NAME_FOR_INDEX, MYF(0), rename_key->old_name.str);
+          goto err;
+        }
+        else if (!my_strcasecmp(system_charset_info, rename_key->new_name.str,
+                                primary_key_name))
+        {
+          my_error(ER_WRONG_NAME_FOR_INDEX, MYF(0), rename_key->new_name.str);
+          goto err;
+        }
+
+        key_name= rename_key->new_name.str;
+        rename_key_it.remove();
+        /*
+          If the user has explicitly renamed the key, we should no longer
+          treat it as generated. Otherwise this key might be automatically
+          dropped by mysql_prepare_create_table() and this will confuse
+          code in fill_alter_inplace_info().
+        */
+        key_info->flags&= ~HA_GENERATED_KEY;
+        break;
+      }
+    }
+
     if (key_info->algorithm == HA_KEY_ALG_LONG_HASH)
     {
       setup_keyinfo_hash(key_info);
@@ -8772,6 +8806,13 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
     }
   }
 
+  if (rename_key_list.elements)
+  {
+    my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), rename_key_list.head()->old_name.str,
+             table->s->table_name.str);
+    goto err;
+  }
+
   if (!create_info->comment.str)
   {
     create_info->comment.str= table->s->comment.str;

sql/sql_yacc.yy

@@ -7732,6 +7732,16 @@ alter_list_item:
             if (unlikely(Lex->add_alter_list($3, $5)))
               MYSQL_YYABORT;
           }
+        | RENAME key_or_index field_ident TO_SYM field_ident
+          {
+            LEX *lex=Lex;
+            Alter_rename_key *ak= new (thd->mem_root)
+                                    Alter_rename_key($3, $5);
+            if (ak == NULL)
+              MYSQL_YYABORT;
+            lex->alter_info.alter_rename_key_list.push_back(ak);
+            lex->alter_info.flags|= ALTER_RENAME_INDEX;
+          }
         | CONVERT_SYM TO_SYM charset charset_name_or_default opt_collate
           {
             if (!$4)

storage/innobase/handler/handler0alter.cc

@@ -3330,6 +3330,14 @@ innobase_check_index_keys(
 				}
 			}
 
+			for (const Alter_inplace_info::Rename_key_pair& pair :
+			     info->rename_keys) {
+				if (0 == strcmp(key.name.str,
+                                                pair.old_key->name.str)) {
+					goto name_ok;
+				}
+			}
+
 			my_error(ER_WRONG_NAME_FOR_INDEX, MYF(0),
                                  key.name.str);
 			return(ER_WRONG_NAME_FOR_INDEX);