I have two tables: feeds and feed_items in a one-to-many relationship.
I selecting feeds from the feeds table and populating “many” items in
the feed_items table for further processing. This happens in a loop.
Before starting to populate feed_items for each feed read in, I execute
the following statement to wipe feed_items table clean:
feed_items.delete_all
I read the ActiveRecords documentation is that is how I understand it.
However, something totally different is happening. I see a one Delete
query each for each row in the feed_item table as below:
^[[4;35;1mFeedItem Destroy (0.000169)^[[0m ^[[0m DELETE FROM
feed_items
WHERE id = 4989515
^[[0m
^[[4;36;1mFeedItem Destroy (0.000178)^[[0m ^[[0;1m DELETE FROM
feed_items
WHERE id = 4989516
^[[0m
^[[4;35;1mFeedItem Destroy (0.000168)^[[0m ^[[0m DELETE FROM
feed_items
WHERE id = 4989517
^[[0m
^[[4;36;1mFeedItem Destroy (0.000166)^[[0m ^[[0;1m DELETE FROM
feed_items
WHERE id = 4989518
^[[0m
^[[4;35;1mFeedItem Destroy (0.000167)^[[0m ^[[0m DELETE FROM
feed_items
WHERE id = 4989519
^[[0m
^[[4;36;1mFeedItem Destroy (0.000179)^[[0m ^[[0;1m DELETE FROM
feed_items
WHERE id = 4989520
This gets pretty expensive for a feed with a large number of feed_items.
I am using Rails 2.1.0 on an Ubuntu 6.06 machine. Any ideas anyone?
Thanks.
Bharat