Hi I am sending a review of this interesting feature.
I found following issues, questions: 1. unclosed tags <optional> in documentation 2. bad name "changeTargetEntry" - should be makeTargetEntry? 3. Why you removed lot of asserts in prepunion.c? These asserts should be valid still 4. make_coresponding_target has wrong formatting 5. error "%s queries with a CORRESPONDING clause must have at least one column with the same name" has wrong formatting, you can show position 6. previous issue is repeated - look on formatting ereport function, please, you can use DETAIL and HINT fields 7. corresponding clause should to contain column list (I am looking to ANSI/SQL 99) - you are using expr_list, what has not sense and probably it has impact on all implementation. 8. typo orderCorrespondingLsit(List *targetlist) 9. I miss more tests for CORRESPONDING BY 10. if I understand to this feature, this query should to work postgres=# SELECT 1 a, 2 b, 3 c UNION CORRESPONDING BY (c,b) SELECT 4 a, 5 b, 6 c, 8 d; ERROR: each UNION query must have the same number of columns LINE 1: ...1 a, 2 b, 3 c UNION CORRESPONDING BY (c,b) SELECT 4 a, 5 b, ... postgres=# create table t1(a int, b int, c int); CREATE TABLE Time: 63,260 ms postgres=# create table t2(a int, b int); CREATE TABLE Time: 57,120 ms postgres=# select * from t1 union corresponding select * from t2; ERROR: each UNION query must have the same number of columns LINE 1: select * from t1 union corresponding select * from t2; If it is your first patch to Postgres, then it is perfect work! The @7 is probably most significant - I dislike a expression list there. name_list should be better there. Regards Pavel
