On Saturday, December 5, 2015 at 9:10:43 AM UTC-8, Mike Pastore wrote:
>
> Hi all,
>
> I'm performing batch updates like so:
>
> World.db.transaction do
> worlds = World
> .where(:id => updates.keys.sort!)
> .for_update
> .all
>
> worlds
> .each { |w| w.randomNumber = updates[w.id] }
>
> World.dataset
> .on_duplicate_key_update(:randomNumber)
> .multi_insert(worlds)
> end
>
> `updates` is a hash where the key is the PK of the record to be updated
> and the value is hopefully self-explanatory. I'm sorting the keys to
> prevent deadlock on the MySQL side and loading the models into memory with
> `#all` because the resultset is quite small and I'd like this to be as
> performant as possible.
>
> My questions are as follows:
>
> - If I submit a PR to expose the `Dataset#on_duplicate_key_update`
> method to Models, would it be accepted? I hate having to write
> `Model.dataset`!
>
> No. You can add the dataset method to all models via:
Sequel::Plugins.def_dataset_methods(Sequel::Model,
[:on_duplicate_key_update])
>
> - Is there a quick and easy way to mark my models as "clean" after the
> batch update is successfully applied?
>
> I'm not sure what you mean. If you mean individual records, adding a
column that stores whether the record is clean should work. If you mean
for the whole table, maybe another table with a single column that stores
the tables that have already been cleaned.
>
> - Are there any other style or performance suggestions you can make?
> This is for some Sinatra/Sequel tests I'm working on for
> FrameworkBenchmarks[1].
>
> Well, for significantly better performance, you'd probably have to drop to
lower levels. As a minor speedup, you could pass the block you are passing
to worlds.each to all, that would eliminate the method call to worlds.each.
I'm not sure the sort! is necessary. I doubt it would make a difference
on PostgreSQL, but maybe on MySQL it does.
Thanks,
Jeremy
--
You received this message because you are subscribed to the Google Groups
"sequel-talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sequel-talk.
For more options, visit https://groups.google.com/d/optout.
