support search_path in SET too (#2261)

Author: vitstn

ydb/library/yql/sql/pg/pg_sql.cpp

@@ -2129,21 +2129,26 @@ class TConverter : public IPGParseEvents {
         }
 
         auto name = to_lower(TString(value->name));
-        if (isSetConfig) {
+        if (name == "search_path") {
             if (ListLength(value->args) != 1) {
                 AddError(TStringBuilder() << "VariableSetStmt, expected 1 arg, but got: " << ListLength(value->args));
                 return nullptr;
             }
             auto val = ListNodeNth(value->args, 0);
+            if (!isSetConfig) {
+                if (NodeTag(val) == T_A_Const) {
+                    val = (const Node*)&CAST_NODE(A_Const, val)->val;
+                } else {
+                    AddError(TStringBuilder() << "VariableSetStmt, expected const for " << value->name << " option");
+                    return nullptr;
+                }
+            }
+
             if (NodeTag(val) != T_String) {
                 AddError(TStringBuilder() << "VariableSetStmt, expected string literal for " << value->name << " option");
                 return nullptr;
             }
             TString rawStr = to_lower(TString(StrVal(val)));
-            if (name != "search_path") {
-                AddError(TStringBuilder() << "VariableSetStmt, set_config doesn't support that option:" << name);
-                return nullptr;
-            }
             if (rawStr != "pg_catalog" && rawStr != "public" && rawStr != "" && rawStr != "information_schema") {
                 AddError(TStringBuilder() << "VariableSetStmt, search path supports only 'information_schema', 'public', 'pg_catalog', '' but got: '" << rawStr << "'");
                 return nullptr;
@@ -2154,6 +2159,13 @@ class TConverter : public IPGParseEvents {
             return State.Statements.back();
         }
 
+        if (isSetConfig) {
+            if (name != "search_path") {
+                AddError(TStringBuilder() << "VariableSetStmt, set_config doesn't support that option:" << name);
+                return nullptr;
+            }
+        }
+
         if (name == "useblocks" || name == "emitaggapply") {
             if (ListLength(value->args) != 1) {
                 AddError(TStringBuilder() << "VariableSetStmt, expected 1 arg, but got: " << ListLength(value->args));