Background I have an ETS table where several processes can write concurrently. This table is very very requested, so having a GenServer as a gatekeeper serializing writes is not an option (it can’t hold the load). Problem The solution to this, given the GenServer limitations, would be to have each …

Then is really going to be a :bag tab = :ets.new(name, [:bag]) :ets.insert(tab, {:failed, url1}) :ets.insert(tab, {:failed, url2}) failed = :ets.take(tab, :failed) |> Keyword.values() # [url1, url2]

Few questions: What’s the reasoning for just using a single key? Usually it’s preferable to split the data over many keys in ets, which makes them easier to query. Is this simply an append and be fine storage? If so simply try to insert and let it fail if an url is already existing (would need ref…

[image] LostKobrakai: What’s the reasoning for just using a single key? Usually it’s preferable to split the data over many keys in ets, which makes them easier to query. I am not interested in querying anything. All I want this table to do is to save URLs whose requests failed. Then, when th…

[image] Fl4m3Ph03n1x: query the table for all URLs Try insert_new(tab, {url,url}) for each url - later foldl over the entire table.

I was actually thinking about using http://erlang.org/doc/man/ets.html#take-2 to get everything with the same key and remove it in one go :smiley:

delete_all_objects doesn’t actually return them, which is something I want in addition to deleting them :stuck_out_tongue:

[image] Taming :ets for High-Performance Software - DockYard A look at the nuances of :ets, and a new library to help with using :ets features. :bag comes with the implementation overhead of checking for duplicates on insert; so unless you explicitly need t…

[image] peerreynders: i.e. may be worth dealing with duplicates after take/2 Could you elaborate ?

It might be better for performance to us :duplicate_bag, which is mentioned to be faster on inserts, and deduplicate the urls after using take/2.

Ahh, so we would be trading a faster insertion for a slower retrieval of information. I get the idea !

Elixir Programming Language Forum

Make atomic updates on ETS key

Questions & Help Questions

Fl4m3Ph03n1x May 7, 2019, 7:47am 10

Could you elaborate ?