Merge pull request #7139 from planetscale/lock_tables

Support for lock and unlock tables

go/vt/sqlparser/analyzer.go

@@ -57,6 +57,8 @@ const (
 	StmtSRollback
 	StmtRelease
 	StmtVStream
+	StmtLockTables
+	StmtUnlockTables
 )
 
 //ASTToStatementType returns a StatementType from an AST stmt
@@ -94,6 +96,10 @@ func ASTToStatementType(stmt Statement) StatementType {
 		return StmtSRollback
 	case *Release:
 		return StmtRelease
+	case *LockTables:
+		return StmtLockTables
+	case *UnlockTables:
+		return StmtUnlockTables
 	default:
 		return StmtUnknown
 	}
@@ -151,6 +157,10 @@ func Preview(sql string) StatementType {
 		return StmtDelete
 	case "savepoint":
 		return StmtSavepoint
+	case "lock":
+		return StmtLockTables
+	case "unlock":
+		return StmtUnlockTables
 	}
 	// For the following statements it is not sufficient to rely
 	// on loweredFirstWord. This is because they are not statements
@@ -231,6 +241,10 @@ func (s StatementType) String() string {
 		return "SAVEPOINT_ROLLBACK"
 	case StmtRelease:
 		return "RELEASE"
+	case StmtLockTables:
+		return "LOCK_TABLES"
+	case StmtUnlockTables:
+		return "UNLOCK_TABLES"
 	default:
 		return "UNKNOWN"
 	}

go/vt/sqlparser/ast.go

@@ -371,6 +371,26 @@ type (
 	// It should be used only as an indicator. It does not contain
 	// the full AST for the statement.
 	OtherAdmin struct{}
+
+	// LockType is an enum for Lock Types
+	LockType int8
+
+	// TableAndLockType contains table and lock association
+	TableAndLockType struct {
+		Table TableExpr
+		Lock  LockType
+	}
+
+	// TableAndLockTypes is a slice of TableAndLockType
+	TableAndLockTypes []*TableAndLockType
+
+	// LockTables represents the lock statement
+	LockTables struct {
+		Tables TableAndLockTypes
+	}
+
+	// UnlockTables represents the unlock statement
+	UnlockTables struct{}
 )
 
 func (*Union) iStatement()             {}
@@ -403,6 +423,8 @@ func (*CreateIndex) iStatement()       {}
 func (*CreateDatabase) iStatement()    {}
 func (*AlterDatabase) iStatement()     {}
 func (*CreateTable) iStatement()       {}
+func (*LockTables) iStatement()        {}
+func (*UnlockTables) iStatement()      {}
 
 func (*DDL) iDDLStatement()         {}
 func (*CreateIndex) iDDLStatement() {}
@@ -2529,3 +2551,16 @@ func (node *CreateTable) Format(buf *TrackedBuffer) {
 		buf.astPrintf(node, " %v", node.TableSpec)
 	}
 }
+
+// Format formats the LockTables node.
+func (node *LockTables) Format(buf *TrackedBuffer) {
+	buf.astPrintf(node, "lock tables %v %s", node.Tables[0].Table, node.Tables[0].Lock.ToString())
+	for i := 1; i < len(node.Tables); i++ {
+		buf.astPrintf(node, ", %v %s", node.Tables[i].Table, node.Tables[i].Lock.ToString())
+	}
+}
+
+// Format formats the UnlockTables node.
+func (node *UnlockTables) Format(buf *TrackedBuffer) {
+	buf.WriteString("unlock tables")
+}

go/vt/sqlparser/ast_funcs.go

@@ -1182,6 +1182,22 @@ func (node CollateAndCharsetType) ToString() string {
 	}
 }
 
+// ToString returns the type as a string
+func (ty LockType) ToString() string {
+	switch ty {
+	case Read:
+		return ReadStr
+	case ReadLocal:
+		return ReadLocalStr
+	case Write:
+		return WriteStr
+	case LowPriorityWrite:
+		return LowPriorityWriteStr
+	default:
+		return "Unknown LockType"
+	}
+}
+
 // AtCount represents the '@' count in ColIdent
 type AtCount int
 

go/vt/sqlparser/constants.go

@@ -188,6 +188,12 @@ const (
 	VitessStr      = "vitess"
 	TraditionalStr = "traditional"
 	AnalyzeStr     = "analyze"
+
+	// Lock Types
+	ReadStr             = "read"
+	ReadLocalStr        = "read local"
+	WriteStr            = "write"
+	LowPriorityWriteStr = "low_priority write"
 )
 
 // Constants for Enum type - AccessMode
@@ -380,3 +386,11 @@ const (
 	CollateType CollateAndCharsetType = iota
 	CharacterSetType
 )
+
+const (
+	UnknownType LockType = iota
+	Read
+	ReadLocal
+	Write
+	LowPriorityWrite
+)

go/vt/sqlparser/parse_test.go

@@ -1516,11 +1516,20 @@ var (
 		input:  "optimize foo",
 		output: "otheradmin",
 	}, {
-		input:  "lock tables foo",
-		output: "otheradmin",
+		input:  "lock tables foo read",
+		output: "lock tables foo read",
 	}, {
-		input:  "unlock tables foo",
-		output: "otheradmin",
+		input:  "lock tables foo write",
+		output: "lock tables foo write",
+	}, {
+		input:  "lock tables foo read local",
+		output: "lock tables foo read local",
+	}, {
+		input:  "lock tables foo low_priority write",
+		output: "lock tables foo low_priority write",
+	}, {
+		input:  "unlock tables",
+		output: "unlock tables",
 	}, {
 		input: "select /* EQ true */ 1 from t where a = true",
 	}, {
@@ -2036,7 +2045,7 @@ func TestKeywords(t *testing.T) {
 		input:  "select /* share and mode as cols */ share, mode from t where share = 'foo'",
 		output: "select /* share and mode as cols */ `share`, `mode` from t where `share` = 'foo'",
 	}, {
-		input:  "select /* unused keywords as cols */ write, varying from t where trailing = 'foo'",
+		input:  "select /* unused keywords as cols */ `write`, varying from t where trailing = 'foo'",
 		output: "select /* unused keywords as cols */ `write`, `varying` from t where `trailing` = 'foo'",
 	}, {
 		input:  "select status from t",