MDEV-13134 Introduce ALTER TABLE attributes ALGORITHM=NOCOPY and ALGORITHM=INSTANT

Introduced new alter algorithm type called NOCOPY & INSTANT for
inplace alter operation.

NOCOPY - Algorithm refuses any alter operation that would
rebuild the clustered index. It is a subset of INPLACE algorithm.

INSTANT - Algorithm allow any alter operation that would
modify only meta data. It is a subset of NOCOPY algorithm.

Introduce new variable called alter_algorithm. The values are
DEFAULT(0), COPY(1), INPLACE(2), NOCOPY(3), INSTANT(4)

Message to deprecate old_alter_table variable and make it alias
for alter_algorithm variable.

alter_algorithm variable for slave is always set to default.

1 files changed, 53 insertions, 4 deletions

diff --git a/sql/sql_alter.h b/sql/sql_alter.h
index 85a7b993e12..268dbc43abd 100644
--- a/sql/sql_alter.h
+++ b/sql/sql_alter.h
@@ -47,14 +47,24 @@ public:
   */
   enum enum_alter_table_algorithm
   {
-    // In-place if supported, copy otherwise.
+/*
+  Use thd->variables.alter_algorithm for alter method. If this is also
+  default then use the fastest possible ALTER TABLE method
+  (INSTANT, NOCOPY, INPLACE, COPY)
+*/
     ALTER_TABLE_ALGORITHM_DEFAULT,
 
+    // Copy if supported, error otherwise.
+    ALTER_TABLE_ALGORITHM_COPY,
+
     // In-place if supported, error otherwise.
     ALTER_TABLE_ALGORITHM_INPLACE,
 
-    // Copy if supported, error otherwise.
-    ALTER_TABLE_ALGORITHM_COPY
+    // No Copy will refuse any operation which does rebuild.
+    ALTER_TABLE_ALGORITHM_NOCOPY,
+
+    // Instant should allow any operation that changes metadata only.
+    ALTER_TABLE_ALGORITHM_INSTANT
   };
 
 
@@ -67,7 +77,7 @@ public:
     // Maximum supported level of concurency for the given operation.
     ALTER_TABLE_LOCK_DEFAULT,
 
-    // Allow concurrent reads & writes. If not supported, give erorr.
+    // Allow concurrent reads & writes. If not supported, give error.
     ALTER_TABLE_LOCK_NONE,
 
     // Allow concurrent reads only. If not supported, give error.
@@ -174,6 +184,45 @@ public:
 
   bool set_requested_lock(const LEX_CSTRING *str);
 
+  /**
+     Returns the algorithm value in the format "algorithm=value"
+  */
+  const char* algorithm() const;
+
+  /**
+     Returns the lock value in the format "lock=value"
+  */
+  const char* lock() const;
+
+  /**
+     Check whether the given result can be supported
+     with the specified user alter algorithm.
+
+     @param  thd            Thread handle
+     @param  result         Operation supported for inplace alter
+     @param  ha_alter_info  Structure describing changes to be done
+                            by ALTER TABLE and holding data during
+                            in-place alter
+     @retval false  Supported operation
+     @retval true   Not supported value
+  */
+  bool supports_algorithm(THD *thd, enum_alter_inplace_result result,
+                          const Alter_inplace_info *ha_alter_info);
+
+  /**
+     Check whether the given result can be supported
+     with the specified user lock type.
+
+     @param  result         Operation supported for inplace alter
+     @param  ha_alter_info  Structure describing changes to be done
+                            by ALTER TABLE and holding data during
+                            in-place alter
+     @retval false  Supported lock type
+     @retval true   Not supported value
+  */
+  bool supports_lock(THD *thd, enum_alter_inplace_result result,
+                     const Alter_inplace_info *ha_alter_info);
+
 private:
   Alter_info &operator=(const Alter_info &rhs); // not implemented
   Alter_info(const Alter_info &rhs);            // not implemented