utils: IsReadOnly returns wrong result when checking SQLs like `exp…

…lain analyze insert ...` (pingcap#381) * update IsReadOnly * add UT * fixup
tiancaiamao · Jul 10, 2019 · fadeae6 · fadeae6
1 parent bd83023
commit fadeae6
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Showing 2 changed files with 26 additions and 1 deletion.
diff --git a/ast/util.go b/ast/util.go
@@ -27,7 +27,9 @@ func IsReadOnly(node Node) bool {
 
 		node.Accept(&checker)
 		return checker.readOnly
-	case *ExplainStmt, *DoStmt:
+	case *ExplainStmt:
+		return !st.Analyze || IsReadOnly(st.Stmt)
+	case *DoStmt:
 		return true
 	default:
 		return false

diff --git a/ast/util_test.go b/ast/util_test.go
@@ -48,6 +48,29 @@ func (s *testCacheableSuite) TestCacheable(c *C) {
 
 	stmt = &DoStmt{}
 	c.Assert(IsReadOnly(stmt), IsTrue)
+
+	stmt = &ExplainStmt{
+		Stmt: &InsertStmt{},
+	}
+	c.Assert(IsReadOnly(stmt), IsTrue)
+
+	stmt = &ExplainStmt{
+		Analyze: true,
+		Stmt:    &InsertStmt{},
+	}
+	c.Assert(IsReadOnly(stmt), IsFalse)
+
+	stmt = &ExplainStmt{
+		Stmt: &SelectStmt{},
+	}
+	c.Assert(IsReadOnly(stmt), IsTrue)
+
+	stmt = &ExplainStmt{
+		Analyze: true,
+		Stmt:    &SelectStmt{},
+	}
+	c.Assert(IsReadOnly(stmt), IsTrue)
+
 }
 
 // CleanNodeText set the text of node and all child node empty.