purge-semantics-added (#4)

* expand-grammar-pg-show-isolation-level

Signed-off-by: General Kroll <generalkroll0@gmail.com>

* purge-semantics-added

Summary:

- `purge` added to grammar.
- Supports GC actions by admin.

Signed-off-by: General Kroll <generalkroll0@gmail.com>

* native-query-pass-through

Summary:

- Native query pass through facility.

Signed-off-by: General Kroll <generalkroll0@gmail.com>

Signed-off-by: General Kroll <generalkroll0@gmail.com>

Author: general-kroll-4-life

go/vt/sqlparser/ast.go

@@ -81,6 +81,21 @@ type (
 		OptExecPayload *ExecVarDef
 	}
 
+	// Purge represents a PURGE statement
+	Purge struct {
+		Await    bool
+		Comments Comments
+		IsGlobal bool
+		Target   TableName
+	}
+
+	// Purge represents a PURGE statement
+	NativeQuery struct {
+		Await       bool
+		Comments    Comments
+		QueryString string
+	}
+
 	Sleep struct {
 		Duration *SQLVal
 	}
@@ -333,6 +348,8 @@ func (*Auth) iStatement()              {}
 func (*Registry) iStatement()          {}
 func (*AuthRevoke) iStatement()        {}
 func (*Exec) iStatement()              {}
+func (*Purge) iStatement()             {}
+func (*NativeQuery) iStatement()       {}
 func (*DescribeTable) iStatement()     {}
 func (*OtherAdmin) iStatement()        {}
 func (*Select) iSelectStatement()      {}
@@ -962,6 +979,14 @@ func (node *Exec) Format(buf *TrackedBuffer) {
 	buf.astPrintf(node, "exec %v %v", node.Comments, node.MethodName)
 }
 
+func (node *Purge) Format(buf *TrackedBuffer) {
+	buf.astPrintf(node, "purge %v %v", node.Comments, node.Target)
+}
+
+func (node *NativeQuery) Format(buf *TrackedBuffer) {
+	buf.astPrintf(node, "purge %v '%v'", node.Comments, node.QueryString)
+}
+
 func (node *ExecSubquery) Format(buf *TrackedBuffer) {
 	buf.astPrintf(node, "( exec %v )", node.Exec)
 }

go/vt/sqlparser/ast_funcs.go

@@ -519,6 +519,23 @@ func NewExec(comments Comments, methodName TableName, execVarDefs []ExecVarDef,
 	}
 }
 
+// NewPurge makes a new Purge.
+func NewPurge(comments Comments, target TableName, isGlobal bool) *Purge {
+	return &Purge{
+		Comments: comments,
+		Target:   target,
+		IsGlobal: isGlobal,
+	}
+}
+
+// NewNativeQuery makes a new NativeQuery.
+func NewNativeQuery(comments Comments, queryString string) *NativeQuery {
+	return &NativeQuery{
+		Comments:    comments,
+		QueryString: queryString,
+	}
+}
+
 // NewExecVarDef makes a new ExecVarDef.
 func NewExecVarDef(colIdent ColIdent, val Expr) ExecVarDef {
 	return ExecVarDef{

go/vt/sqlparser/external_visitor.go

@@ -70,6 +70,8 @@ func (node *ParenTableExpr) Accept(vis SQLAstVisitor) error       { return vis.V
 func (node *PartitionDefinition) Accept(vis SQLAstVisitor) error  { return vis.Visit(node) }
 func (node Partitions) Accept(vis SQLAstVisitor) error            { return vis.Visit(node) }
 func (node *PartitionSpec) Accept(vis SQLAstVisitor) error        { return vis.Visit(node) }
+func (node *Purge) Accept(vis SQLAstVisitor) error                { return vis.Visit(node) }
+func (node *NativeQuery) Accept(vis SQLAstVisitor) error          { return vis.Visit(node) }
 func (node *RangeCond) Accept(vis SQLAstVisitor) error            { return vis.Visit(node) }
 func (node ReferenceAction) Accept(vis SQLAstVisitor) error       { return vis.Visit(node) }
 func (node *Registry) Accept(vis SQLAstVisitor) error             { return vis.Visit(node) }