Refactor Show plans

go/vt/sqlparser/ast.go

@@ -753,40 +753,53 @@ func (node *AlterDatabase) GetDatabaseName() string {
 // of SelectStatement.
 func (*ParenSelect) iStatement() {}
 
-//ShowInternal will represent all the show statement types.
-type ShowInternal interface {
-	isShowInternal()
-	SQLNode
-}
+type (
 
-//ShowLegacy is of ShowInternal type, holds the legacy show ast struct.
-type ShowLegacy struct {
-	Extended               string
-	Type                   string
-	OnTable                TableName
-	Table                  TableName
-	ShowTablesOpt          *ShowTablesOpt
-	Scope                  Scope
-	ShowCollationFilterOpt Expr
-}
+	// ShowInternal will represent all the show statement types.
+	ShowInternal interface {
+		isShowInternal()
+		SQLNode
+	}
 
-//ShowColumns is of ShowInternal type, holds the show columns statement.
-type ShowColumns struct {
-	Full   string
-	Table  TableName
-	DbName string
-	Filter *ShowFilter
-}
+	// ShowLegacy is of ShowInternal type, holds the legacy show ast struct.
+	ShowLegacy struct {
+		Extended               string
+		Type                   string
+		OnTable                TableName
+		Table                  TableName
+		ShowTablesOpt          *ShowTablesOpt
+		Scope                  Scope
+		ShowCollationFilterOpt Expr
+	}
 
-// ShowTableStatus is of ShowInternal type, holds SHOW TABLE STATUS queries.
-type ShowTableStatus struct {
-	DatabaseName string
-	Filter       *ShowFilter
-}
+	// ShowColumns is of ShowInternal type, holds the show columns statement.
+	ShowColumns struct {
+		Full   string
+		Table  TableName
+		DbName string
+		Filter *ShowFilter
+	}
+
+	// ShowTableStatus is of ShowInternal type, holds SHOW TABLE STATUS queries.
+	ShowTableStatus struct {
+		DatabaseName string
+		Filter       *ShowFilter
+	}
+
+	// ShowCommandType represents the show statement type.
+	ShowCommandType int8
+
+	// ShowBasic is of ShowInternal type, holds Simple SHOW queries with a filter.
+	ShowBasic struct {
+		Command ShowCommandType
+		Filter  *ShowFilter
+	}
+)
 
 func (*ShowLegacy) isShowInternal()      {}
 func (*ShowColumns) isShowInternal()     {}
 func (*ShowTableStatus) isShowInternal() {}
+func (*ShowBasic) isShowInternal()       {}
 
 // InsertRows represents the rows for an INSERT statement.
 type InsertRows interface {
@@ -2551,6 +2564,11 @@ func (node *ShowTableStatus) Format(buf *TrackedBuffer) {
 	buf.astPrintf(node, "%v", node.Filter)
 }
 
+// Format formats the node.
+func (node *ShowBasic) Format(buf *TrackedBuffer) {
+	buf.astPrintf(node, "show%s%v", node.Command.ToString(), node.Filter)
+}
+
 // Format formats the node.
 func (node *SelectInto) Format(buf *TrackedBuffer) {
 	if node == nil {

go/vt/sqlparser/ast_funcs.go

@@ -1198,6 +1198,32 @@ func (ty LockType) ToString() string {
 	}
 }
 
+// ToString returns ShowCommandType as a string
+func (ty ShowCommandType) ToString() string {
+	switch ty {
+	case Charset:
+		return CharsetStr
+	case Collation:
+		return CollationStr
+	case Database:
+		return DatabaseStr
+	case Function:
+		return FunctionStr
+	case Procedure:
+		return ProcedureStr
+	case StatusGlobal:
+		return StatusGlobalStr
+	case StatusSession:
+		return StatusSessionStr
+	case VariableGlobal:
+		return VariableGlobalStr
+	case VariableSession:
+		return VariableSessionStr
+	default:
+		return "Unknown ShowCommandType"
+	}
+}
+
 // AtCount represents the '@' count in ColIdent
 type AtCount int
 

go/vt/sqlparser/constants.go

@@ -147,7 +147,6 @@ const (
 	// ConvertType.Operator
 	CharacterSetStr = " character set"
 	NoOperatorStr   = ""
-	CharsetStr      = "charset"
 
 	// CollateAndCharset.Type
 	CollateStr = " collate"
@@ -194,6 +193,17 @@ const (
 	ReadLocalStr        = "read local"
 	WriteStr            = "write"
 	LowPriorityWriteStr = "low_priority write"
+
+	// ShowCommand Types
+	CharsetStr         = " charset"
+	CollationStr       = " collation"
+	DatabaseStr        = " databases"
+	FunctionStr        = " function status"
+	ProcedureStr       = " procedure status"
+	StatusGlobalStr    = " global status"
+	StatusSessionStr   = " status"
+	VariableGlobalStr  = " global variables"
+	VariableSessionStr = " variables"
 )
 
 // Constants for Enum type - AccessMode
@@ -387,10 +397,25 @@ const (
 	CharacterSetType
 )
 
+// LockType constants
 const (
-	UnknownType LockType = iota
+	UnknownLockType LockType = iota
 	Read
 	ReadLocal
 	Write
 	LowPriorityWrite
 )
+
+// ShowCommandType constants
+const (
+	UnknownCommandType ShowCommandType = iota
+	Charset
+	Collation
+	Database
+	Function
+	Procedure
+	StatusGlobal
+	StatusSession
+	VariableGlobal
+	VariableSession
+)

go/vt/sqlparser/parse_test.go

@@ -1297,10 +1297,10 @@ var (
 		output: "show databases like '%'",
 	}, {
 		input:  "show schemas",
-		output: "show schemas",
+		output: "show databases",
 	}, {
 		input:  "show schemas like '%'",
-		output: "show schemas like '%'",
+		output: "show databases like '%'",
 	}, {
 		input:  "show engine INNODB",
 		output: "show engine",
@@ -1344,11 +1344,9 @@ var (
 		input:  "show privileges",
 		output: "show privileges",
 	}, {
-		input:  "show procedure code p",
-		output: "show procedure",
+		input: "show procedure code p",
 	}, {
-		input:  "show procedure status",
-		output: "show procedure",
+		input: "show procedure status",
 	}, {
 		input:  "show processlist",
 		output: "show processlist",
@@ -1378,7 +1376,7 @@ var (
 		output: "show global status",
 	}, {
 		input:  "show session status",
-		output: "show session status",
+		output: "show status",
 	}, {
 		input: "show table status",
 	}, {
@@ -1441,11 +1439,13 @@ var (
 		output: "show global variables",
 	}, {
 		input:  "show session variables",
-		output: "show session variables",
+		output: "show variables",
 	}, {
-		input: "show vitess_keyspaces",
+		input:  "show vitess_keyspaces",
+		output: "show databases",
 	}, {
-		input: "show vitess_keyspaces like '%'",
+		input:  "show vitess_keyspaces like '%'",
+		output: "show databases like '%'",
 	}, {
 		input: "show vitess_shards",
 	}, {