Add support for PARTITION BY HASH in CREATE|ALTER TABLE statements

Author: atavakoliyext

ast.go

@@ -1046,6 +1046,7 @@ func (node *DDL) walkSubtree(visit Visit) error {
 const (
 	ReorganizeStr                 = "reorganize partition"
 	PartitionByRangeStr           = "partition by range"
+	PartitionByHashStr            = "partition by hash"
 	AddPartitionStr               = "add partition"
 	DropPartitionStr              = "drop partition"
 	DiscardPartitionTablespaceStr = "discard partition"
@@ -1073,6 +1074,7 @@ type PartitionSpec struct {
 	Table       TableName
 	Validation  string
 	Expr        Expr
+	IsLinear    bool
 	IsColumns   bool
 	ColumnList  Columns
 	Definitions []*PartitionDefinition
@@ -1127,6 +1129,16 @@ func (node *PartitionSpec) Format(buf *TrackedBuffer) {
 		} else {
 			buf.Myprintf("%s (%v) (", node.Action, node.Expr)
 		}
+	case PartitionByHashStr:
+		if node.IsLinear {
+			buf.Myprintf("partition by linear hash (%v)", node.Expr)
+		} else {
+			buf.Myprintf("%s (%v)", node.Action, node.Expr)
+		}
+		if node.Number != "" {
+			buf.Myprintf(" partitions %s", node.Number)
+		}
+		return
 	default:
 		panic("unimplemented")
 	}

parse_test.go

@@ -871,6 +871,12 @@ var (
 	}, {
 		input:  "alter table a partition by range (id) (partition p0 values less than (10), partition p1 values less than (maxvalue))",
 		output: "alter table a partition by range (id) (partition p0 values less than (10), partition p1 values less than (maxvalue))",
+	}, {
+		input:  "alter table tbl_hash_a partition by hash (col_a) partitions 8",
+		output: "alter table tbl_hash_a partition by hash (col_a) partitions 8",
+	}, {
+		input:  "alter table tbl_hash_b partition by linear hash (col_b) partitions 4",
+		output: "alter table tbl_hash_b partition by linear hash (col_b) partitions 4",
 	}, {
 		input:  "alter table tbl_part add partition (partition p2 values less than (100))",
 		output: "alter table tbl_part add partition (partition p2 values less than (100))",
@@ -2831,6 +2837,12 @@ func TestCreateTable(t *testing.T) {
 		"create table t (id int) partition by range (id) (partition p0 values less than (10) engine =)",
 		// STORAGE ENGINE option requires the ENGINE keyword.
 		"create table t (id int) partition by range (id) (partition p0 values less than (10) storage = InnoDB)",
+		// HASH expression must be parenthesized.
+		"create table t (id int) partition by hash id partitions 8",
+		// PARTITIONS requires an integer value.
+		"create table t (id int) partition by hash (id) partitions",
+		// PARTITIONS keyword must not be misspelled.
+		"create table t (id int) partition by hash (id) partition 8",
 	}
 	for _, sql := range invalidCreateTablePartitionSQL {
 		tree, err := Parse(sql)
@@ -3135,6 +3147,24 @@ func TestCreateTable(t *testing.T) {
 			"\tid bigint unsigned not null auto_increment,\n" +
 			"\tprimary key (id)\n" +
 			") partition by range (id) (partition p0 values less than (100) engine InnoDB, partition p1 values less than (maxvalue) engine InnoDB)",
+	}, {
+		input: "create table tbl_hash_main (\n" +
+			"	col_a bigint unsigned not null,\n" +
+			"	primary key (col_a)\n" +
+			") partition by hash (col_a) partitions 10",
+		output: "create table tbl_hash_main (\n" +
+			"\tcol_a bigint unsigned not null,\n" +
+			"\tprimary key (col_a)\n" +
+			") partition by hash (col_a) partitions 10",
+	}, {
+		input: "create table tbl_hash_linear (\n" +
+			"	col_b bigint unsigned not null,\n" +
+			"	primary key (col_b)\n" +
+			") partition by linear hash (col_b) partitions 6",
+		output: "create table tbl_hash_linear (\n" +
+			"\tcol_b bigint unsigned not null,\n" +
+			"\tprimary key (col_b)\n" +
+			") partition by linear hash (col_b) partitions 6",
 	}, {
 		input: "create table t_part (\n" +
 			"	c_id bigint unsigned not null,\n" +