Queryset Preload Methods Repeat Keys

[DazedNConfused-]

When writing a Query that involves preloading a foreign-key object (for example: DBModel.NewObjectQuerySet(DBConn).PrimaryKeyEq(pk).PreloadNestedObject()), the Nested Objects are fetched in a query that has a WHERE clause with all the foreign-key IDs.

The problem arises when said Nested Objects are the same for multiple instances of Object (a many-to-one relationship); the underlying query repeats the key. For example:

Object PK	Nested Object FK
1	1
2	2
3	1
4	1
5	1

Results in the following query when using PreloadNestedObject():

SELECT * FROM NestedObject WHERE pk IN (1, 1, 1, 1, 2);

This massively slows down the underlying queries when fetching fairly average resultsets (tens of seconds every 30000 simple records).

[jirfag]

@DazedNConfused- thank you for issue and nice formatting, but I can't control this behaviour in go-queryset. It's a gorm issue. As I understood it was fixed in this commit, please try updating gorm

[DazedNConfused-]

Thank you for the heads-up! I have updated gorm but the behaviour persists. Perhaps it wasn't pushed to upstream yet.