Strange Active::Record behavior, StatementInvalid exception thrown twice?

Rails
1

Hi,

I’m a bit puzzled with an ActiveRecord::StatementInvalid exception
that’s apparently being thrown twice.

I’m using Rails 2.3.3 and Postgres, and inside the Feed Model I have
something like:

has_many :entries, :dependent => :delete_all

def process_feed
…
process_feed_entries

log saving feed

save! # will fail if an exception is thrown below
end

def process_feed_entries
…
begin
# log saving entry
entry.save! # can fail because of duplicate key values
rescue ActiveRecord::StatementInvalid => e
# log exception caught
# log the error in the db (Log Model)
end
end

DB log:

  • Saving entry
    BEGIN
    PGError: ERROR: duplicate key value … : INSERT INTO “entries” …
    ROLLBACK
  • Exception caught
    BEGIN
    INSERT INTO “logs” …
    COMMIT
  • Saving feed
    BEGIN
    UPDATE “feeds” …
    PGError: ERROR: duplicate key value … : INSERT INTO “entries”
    ROLLBACK
    ActiveRecord::StatementInvalid: PGError: ERROR: duplicate key …
    Stack trace

The last exception that terminates execution was (or should have been)
caught inside the begin/rescue block. Why is it thrown again when the
feed is saved, if the transaction was rolled back?

Any hints much appreciated!

Thanks,

–
Adriano

2

On Aug 26, 11:56 am, Adriano N. [email protected] wrote:

has_many :entries, :dependent => :delete_all
save! # will fail if an exception is thrown below

Nothing like explaining your problem to others :slight_smile:

I figure feed.save tries to save the associated entry and that throws
the exception again.

I have to delete the offending entry inside the rescue clause.

Thanks,

–
Adriano

3

On Aug 26, 3:56 pm, Adriano N. [email protected] wrote:

def process_feed
entry.save! # can fail because of duplicate key values
Is entry a member of the entries collection ? If so then the docs on
associations state

“All unsaved (new_record? == true) members of the collection are
automatically saved when the parent is saved.”
ie when you call feed.save! unsaved association members are saved.

Fred

4

On Aug 26, 7:39 pm, Frederick C. [email protected]
wrote:

On Aug 26, 3:56 pm, Adriano N. [email protected] wrote:

Is entry a member of the entries collection ? If so then the docs on
associations state

Oops, you beat me to it !

Fred