Duplicate 'SHOW FIELDS' statements when inserting data for p

Rails
1

I am using a HABTM relationship for my app. When inserting data for a
number of collection objects,
I am seeing a ‘SHOW FIELD’ query as each row is inserted:

0m
[4;36;1melements_tags Columns (0.020000) [0m [0;1mSHOW FIELDS
FROM elements_tags [0m
[4;35;1mSQL (0.010000) [0m [0mINSERT INTO elements_tags
(element_id, tag_id, add_flag) VALUES (3140, 2, NULL) [0m
[4;36;1melements_items Columns (0.010000) [0m [0;1mSHOW FIELDS
FROM elements_items [0m
[4;35;1mSQL (0.010000) [0m [0mINSERT INTO elements_items
(item_id, element_id, add_flag) VALUES (94, 3140, 0) [0m
[4;36;1mitems_releases Columns (0.020000) [0m [0;1mSHOW FIELDS
FROM items_releases [0m
[4;35;1mSQL (0.020000) [0m [0mINSERT INTO items_releases
(item_id, release_id) VALUES (94, 97) [0m
[4;36;1mitems_releases Columns (0.010000) [0m [0;1mSHOW FIELDS
FROM items_releases [0m
[4;35;1mSQL (0.020000) [0m [0mINSERT INTO items_releases
(item_id, release_id) VALUES (91, 97) [0m
[4;36;1mitems_releases Columns (0.020000) [0m [0;1mSHOW FIELDS
FROM items_releases [0m
[4;35;1mSQL (0.010000) [0m [0mINSERT INTO items_releases
(item_id, release_id) VALUES (92, 97) [0m
[4;

What would cause this? From what I understand, the column meta data
should be loaded only once as
each model is loaded for the first time. This happens under both
Oracle and MySQL. I am
running with my environment set to production.

Thanks in advance,
Don Mc

2

Any ideas,anyone?

3

Don.Mc wrote:

[4;35;1mSQL (0.020000) [0m [0mINSERT INTO items_releases
Oracle and MySQL. I am
running with my environment set to production.

Rails currently doesn’t cache columns of HABTM join tables.
The fix would probably only involve changing line

http://dev.rubyonrails.org/browser/trunk/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb#L84

to read @columns ||= …

Give it a try, or open a ticket.

–
We develop, watch us RoR, in numbers too big to ignore.

4

Thanks! I will give it a try.

Regards,
Don

5

Don.Mc wrote:

Thanks! I will give it a try.

Thinking about it, the change I suggested will only get
rid of the last two SHOW FIELDS in your post; the join table
fields will still be fetched separately for each parent object.

A proper fix would have to cache the columns inside the
association reflection.

–
We develop, watch us RoR, in numbers too big to ignore.

6

OK, will look at that. Thanks again.