MDEV-16288 ALTER TABLE…ALGORITHM=DEFAULT does not override alter_algo…

…rithm

- ALTER_ALGORITHM should be substituted when there is no mention of
algorithm in alter statement.
- Introduced algorithm(thd) in Alter_info. It returns the
user requested algorithm. If user doesn't specify algorithm explicitly then
it returns alter_algorithm variable.
- changed algorithm() to get_algorithm(thd) to return algorithm name for
displaying the error.
- set_requested_algorithm(algo_value) to avoid direct assignment on
requested_algorithm variable.
- Avoid direct access of requested_algorithm to encapsulate
requested_algorithm variable

mysql-test/suite/innodb/r/alter_algorithm,INPLACE.rdiff

@@ -1,6 +1,6 @@
---- alter_algorithm.result
-+++ alter_algorithm.reject
-@@ -7,40 +7,40 @@
+--- alter_algorithm.result	2020-04-30 21:39:48.923115511 +0530
++++ alter_algorithm.reject	2020-04-30 21:45:04.131642093 +0530
+@@ -7,43 +7,43 @@
  INSERT INTO t1(f1, f2, f3) VALUES(1, 1, 1);
  SELECT @@alter_algorithm;
  @@alter_algorithm
@@ -54,11 +54,16 @@
 -affected rows: 1
 -info: Records: 1  Duplicates: 0  Warnings: 0
 +affected rows: 0
++info: Records: 0  Duplicates: 0  Warnings: 0
+ ALTER TABLE t1 FORCE, ALGORITHM=DEFAULT;
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
 +info: Records: 0  Duplicates: 0  Warnings: 0
  DROP TABLE t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT PRIMARY KEY, f2 INT NOT NULL,
-@@ -53,22 +53,22 @@
+@@ -56,22 +56,22 @@
  FOREIGN KEY fidx(f1) REFERENCES t1(f1))ENGINE=INNODB;
  INSERT INTO t1(f1, f2, f4, f5) VALUES(1, 2, 3, 4);
  ALTER TABLE t1 ADD INDEX idx1(f4), page_compressed=1;
@@ -91,7 +96,7 @@
  DROP TABLE t2, t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT NOT NULL,
-@@ -81,27 +81,27 @@
+@@ -84,28 +84,27 @@
  INSERT INTO t1(f1, f2) VALUES(1, 1);
  # Add column at the end of the table
  ALTER TABLE t1 ADD COLUMN f4 char(100) default 'BIG WALL';
@@ -119,7 +124,9 @@
 +info: Records: 0  Duplicates: 0  Warnings: 0
  # Rename table
  ALTER TABLE t1 RENAME t3;
- affected rows: 0
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
  # Drop Virtual Column
  ALTER TABLE t3 DROP COLUMN vcol;
 -affected rows: 1
@@ -129,7 +136,7 @@
  # Column length varies
  ALTER TABLE t2 CHANGE f3 f3 VARCHAR(20);
  affected rows: 0
-@@ -109,12 +109,12 @@
+@@ -113,12 +112,12 @@
  SET foreign_key_checks = 0;
  affected rows: 0
  ALTER TABLE t3 ADD FOREIGN KEY fidx(f2) REFERENCES t2(f1);

mysql-test/suite/innodb/r/alter_algorithm,INSTANT.rdiff

@@ -1,6 +1,6 @@
---- alter_algorithm.result
-+++ alter_algorithm.reject
-@@ -7,40 +7,32 @@
+--- alter_algorithm.result	2020-04-30 21:39:48.923115511 +0530
++++ alter_algorithm.reject	2020-04-30 21:47:08.245465018 +0530
+@@ -7,43 +7,35 @@
  INSERT INTO t1(f1, f2, f3) VALUES(1, 1, 1);
  SELECT @@alter_algorithm;
  @@alter_algorithm
@@ -47,10 +47,15 @@
 -affected rows: 1
 -info: Records: 1  Duplicates: 0  Warnings: 0
 +Got one of the listed errors
+ ALTER TABLE t1 FORCE, ALGORITHM=DEFAULT;
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
++info: Records: 0  Duplicates: 0  Warnings: 0
  DROP TABLE t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT PRIMARY KEY, f2 INT NOT NULL,
-@@ -53,22 +45,17 @@
+@@ -56,22 +48,17 @@
  FOREIGN KEY fidx(f1) REFERENCES t1(f1))ENGINE=INNODB;
  INSERT INTO t1(f1, f2, f4, f5) VALUES(1, 2, 3, 4);
  ALTER TABLE t1 ADD INDEX idx1(f4), page_compressed=1;
@@ -78,7 +83,7 @@
  DROP TABLE t2, t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT NOT NULL,
-@@ -81,27 +68,27 @@
+@@ -84,28 +71,27 @@
  INSERT INTO t1(f1, f2) VALUES(1, 1);
  # Add column at the end of the table
  ALTER TABLE t1 ADD COLUMN f4 char(100) default 'BIG WALL';
@@ -106,7 +111,9 @@
 +info: Records: 0  Duplicates: 0  Warnings: 0
  # Rename table
  ALTER TABLE t1 RENAME t3;
- affected rows: 0
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
  # Drop Virtual Column
  ALTER TABLE t3 DROP COLUMN vcol;
 -affected rows: 1
@@ -116,7 +123,7 @@
  # Column length varies
  ALTER TABLE t2 CHANGE f3 f3 VARCHAR(20);
  affected rows: 0
-@@ -109,12 +96,12 @@
+@@ -113,12 +99,12 @@
  SET foreign_key_checks = 0;
  affected rows: 0
  ALTER TABLE t3 ADD FOREIGN KEY fidx(f2) REFERENCES t2(f1);

mysql-test/suite/innodb/r/alter_algorithm,NOCOPY.rdiff

@@ -1,6 +1,6 @@
---- alter_algorithm.result
-+++ alter_algorithm.reject
-@@ -7,40 +7,32 @@
+--- alter_algorithm.result	2020-04-30 21:39:48.923115511 +0530
++++ alter_algorithm.reject	2020-04-30 21:52:10.785967739 +0530
+@@ -7,43 +7,35 @@
  INSERT INTO t1(f1, f2, f3) VALUES(1, 1, 1);
  SELECT @@alter_algorithm;
  @@alter_algorithm
@@ -47,10 +47,15 @@
 -affected rows: 1
 -info: Records: 1  Duplicates: 0  Warnings: 0
 +Got one of the listed errors
+ ALTER TABLE t1 FORCE, ALGORITHM=DEFAULT;
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
++info: Records: 0  Duplicates: 0  Warnings: 0
  DROP TABLE t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT PRIMARY KEY, f2 INT NOT NULL,
-@@ -53,22 +45,22 @@
+@@ -56,22 +48,22 @@
  FOREIGN KEY fidx(f1) REFERENCES t1(f1))ENGINE=INNODB;
  INSERT INTO t1(f1, f2, f4, f5) VALUES(1, 2, 3, 4);
  ALTER TABLE t1 ADD INDEX idx1(f4), page_compressed=1;
@@ -83,7 +88,7 @@
  DROP TABLE t2, t1;
  affected rows: 0
  CREATE TABLE t1(f1 INT NOT NULL,
-@@ -81,27 +73,27 @@
+@@ -84,28 +76,27 @@
  INSERT INTO t1(f1, f2) VALUES(1, 1);
  # Add column at the end of the table
  ALTER TABLE t1 ADD COLUMN f4 char(100) default 'BIG WALL';
@@ -111,7 +116,9 @@
 +info: Records: 0  Duplicates: 0  Warnings: 0
  # Rename table
  ALTER TABLE t1 RENAME t3;
- affected rows: 0
+-affected rows: 1
+-info: Records: 1  Duplicates: 0  Warnings: 0
++affected rows: 0
  # Drop Virtual Column
  ALTER TABLE t3 DROP COLUMN vcol;
 -affected rows: 1
@@ -121,7 +128,7 @@
  # Column length varies
  ALTER TABLE t2 CHANGE f3 f3 VARCHAR(20);
  affected rows: 0
-@@ -109,12 +101,12 @@
+@@ -113,12 +104,12 @@
  SET foreign_key_checks = 0;
  affected rows: 0
  ALTER TABLE t3 ADD FOREIGN KEY fidx(f2) REFERENCES t2(f1);

mysql-test/suite/innodb/r/alter_algorithm.result

@@ -41,6 +41,9 @@ info: Records: 1  Duplicates: 0  Warnings: 0
 ALTER TABLE t1 ENGINE=INNODB;
 affected rows: 1
 info: Records: 1  Duplicates: 0  Warnings: 0
+ALTER TABLE t1 FORCE, ALGORITHM=DEFAULT;
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
 DROP TABLE t1;
 affected rows: 0
 CREATE TABLE t1(f1 INT PRIMARY KEY, f2 INT NOT NULL,
@@ -97,7 +100,8 @@ affected rows: 1
 info: Records: 1  Duplicates: 0  Warnings: 0
 # Rename table
 ALTER TABLE t1 RENAME t3;
-affected rows: 0
+affected rows: 1
+info: Records: 1  Duplicates: 0  Warnings: 0
 # Drop Virtual Column
 ALTER TABLE t3 DROP COLUMN vcol;
 affected rows: 1

mysql-test/suite/innodb/r/alter_algorithm2.result

@@ -54,3 +54,23 @@ DROP PROCEDURE p1;
 affected rows: 0
 DROP PROCEDURE p2;
 affected rows: 0
+CREATE TABLE t1(id INT PRIMARY KEY,
+col1 INT UNSIGNED NOT NULL UNIQUE)ENGINE=InnoDB;
+affected rows: 0
+INSERT INTO t1 VALUES(1,1),(2,2),(3,3);
+affected rows: 3
+info: Records: 3  Duplicates: 0  Warnings: 0
+SET ALTER_ALGORITHM=INSTANT;
+affected rows: 0
+ALTER TABLE t1 DROP COLUMN col1;
+ERROR 0A000: ALGORITHM=INSTANT is not supported for this operation. Try ALGORITHM=INPLACE
+ALTER TABLE t1 DROP COLUMN col1, ALGORITHM=NOCOPY;
+ERROR 0A000: ALGORITHM=NOCOPY is not supported for this operation. Try ALGORITHM=INPLACE
+ALTER TABLE t1 DROP COLUMN col1, ALGORITHM=DEFAULT;
+affected rows: 0
+info: Records: 0  Duplicates: 0  Warnings: 0
+ALTER TABLE t1 DROP PRIMARY KEY, ALGORITHM=DEFAULT;
+affected rows: 3
+info: Records: 3  Duplicates: 0  Warnings: 0
+DROP TABLE t1;
+affected rows: 0

mysql-test/suite/innodb/t/alter_algorithm.test

@@ -55,6 +55,10 @@ ALTER TABLE t1 ROW_FORMAT=COMPRESSED;
 --error $error_code
 ALTER TABLE t1 ENGINE=INNODB;
 
+# Irrespective of alter_algorithm value, the following command
+# should succeed because of explicitly mentioning ALGORTHM=DEFAULT
+ALTER TABLE t1 FORCE, ALGORITHM=DEFAULT;
+
 DROP TABLE t1;
 --disable_info
 

mysql-test/suite/innodb/t/alter_algorithm2.test

@@ -44,4 +44,16 @@ call p1();
 DROP TABLE t1;
 DROP PROCEDURE p1;
 DROP PROCEDURE p2;
+
+CREATE TABLE t1(id INT PRIMARY KEY,
+	        col1 INT UNSIGNED NOT NULL UNIQUE)ENGINE=InnoDB;
+INSERT INTO t1 VALUES(1,1),(2,2),(3,3);
+SET ALTER_ALGORITHM=INSTANT;
+--error ER_ALTER_OPERATION_NOT_SUPPORTED
+ALTER TABLE t1 DROP COLUMN col1;
+--error ER_ALTER_OPERATION_NOT_SUPPORTED
+ALTER TABLE t1 DROP COLUMN col1, ALGORITHM=NOCOPY;
+ALTER TABLE t1 DROP COLUMN col1, ALGORITHM=DEFAULT;
+ALTER TABLE t1 DROP PRIMARY KEY, ALGORITHM=DEFAULT;
+DROP TABLE t1;
 --disable_info

sql/sql_alter.cc

@@ -69,6 +69,10 @@ bool Alter_info::set_requested_algorithm(const LEX_CSTRING *str)
   return false;
 }
 
+void Alter_info::set_requested_algorithm(enum_alter_table_algorithm algo_val)
+{
+  requested_algorithm= algo_val;
+}
 
 bool Alter_info::set_requested_lock(const LEX_CSTRING *str)
 {
@@ -86,13 +90,16 @@ bool Alter_info::set_requested_lock(const LEX_CSTRING *str)
   return false;
 }
 
-const char* Alter_info::algorithm() const
+const char* Alter_info::algorithm_clause(THD *thd) const
 {
-  switch (requested_algorithm) {
+  switch (algorithm(thd)) {
   case ALTER_TABLE_ALGORITHM_INPLACE:
     return "ALGORITHM=INPLACE";
   case ALTER_TABLE_ALGORITHM_COPY:
     return "ALGORITHM=COPY";
+  case ALTER_TABLE_ALGORITHM_NONE:
+    DBUG_ASSERT(0);
+    /* Fall through */
   case ALTER_TABLE_ALGORITHM_DEFAULT:
     return "ALGORITHM=DEFAULT";
   case ALTER_TABLE_ALGORITHM_NOCOPY:
@@ -123,9 +130,6 @@ const char* Alter_info::lock() const
 bool Alter_info::supports_algorithm(THD *thd, enum_alter_inplace_result result,
                                     const Alter_inplace_info *ha_alter_info)
 {
-  if (requested_algorithm == Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT)
-    requested_algorithm = (Alter_info::enum_alter_table_algorithm) thd->variables.alter_algorithm;
-
   switch (result) {
   case HA_ALTER_INPLACE_EXCLUSIVE_LOCK:
   case HA_ALTER_INPLACE_SHARED_LOCK:
@@ -134,26 +138,26 @@ bool Alter_info::supports_algorithm(THD *thd, enum_alter_inplace_result result,
      return false;
   case HA_ALTER_INPLACE_COPY_NO_LOCK:
   case HA_ALTER_INPLACE_COPY_LOCK:
-    if (requested_algorithm >= Alter_info::ALTER_TABLE_ALGORITHM_NOCOPY)
+    if (algorithm(thd) >= Alter_info::ALTER_TABLE_ALGORITHM_NOCOPY)
     {
-      ha_alter_info->report_unsupported_error(algorithm(),
+      ha_alter_info->report_unsupported_error(algorithm_clause(thd),
                                               "ALGORITHM=INPLACE");
       return true;
     }
     return false;
   case HA_ALTER_INPLACE_NOCOPY_NO_LOCK:
   case HA_ALTER_INPLACE_NOCOPY_LOCK:
-    if (requested_algorithm == Alter_info::ALTER_TABLE_ALGORITHM_INSTANT)
+    if (algorithm(thd) == Alter_info::ALTER_TABLE_ALGORITHM_INSTANT)
     {
       ha_alter_info->report_unsupported_error("ALGORITHM=INSTANT",
                                               "ALGORITHM=NOCOPY");
       return true;
     }
     return false;
   case HA_ALTER_INPLACE_NOT_SUPPORTED:
-    if (requested_algorithm >= Alter_info::ALTER_TABLE_ALGORITHM_INPLACE)
+    if (algorithm(thd) >= Alter_info::ALTER_TABLE_ALGORITHM_INPLACE)
     {
-      ha_alter_info->report_unsupported_error(algorithm(),
+      ha_alter_info->report_unsupported_error(algorithm_clause(thd),
 					      "ALGORITHM=COPY");
       return true;
     }
@@ -174,7 +178,7 @@ bool Alter_info::supports_lock(THD *thd, enum_alter_inplace_result result,
   case HA_ALTER_INPLACE_EXCLUSIVE_LOCK:
     // If SHARED lock and no particular algorithm was requested, use COPY.
     if (requested_lock == Alter_info::ALTER_TABLE_LOCK_SHARED &&
-        requested_algorithm == Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT &&
+        algorithm(thd) == Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT &&
         thd->variables.alter_algorithm ==
                 Alter_info::ALTER_TABLE_ALGORITHM_DEFAULT)
          return false;
@@ -237,6 +241,14 @@ bool Alter_info::vers_prohibited(THD *thd) const
   return false;
 }
 
+Alter_info::enum_alter_table_algorithm
+Alter_info::algorithm(const THD *thd) const
+{
+  if (requested_algorithm == ALTER_TABLE_ALGORITHM_NONE)
+   return (Alter_info::enum_alter_table_algorithm) thd->variables.alter_algorithm;
+  return requested_algorithm;
+}
+
 
 Alter_table_ctx::Alter_table_ctx()
   : datetime_field(NULL), error_if_not_empty(false),