Hello, we have this situation right now: Every time we make a sale we need to emit a document with a unique and sequential document number. These numbers belong to a sequence based on the product sold (each document is for one product), we have a reserved range of numbers for each product, the ran…

ksuid generate unique, sortable id. [image] ksuid ksuid is a zero dependency Elixir library for generating KSUIDs. You could (post/)prepend with your product id if You want. Now your solution with a Genserver per product could work… it depends how much do Y…

I saw something like ksuid before, the problem is that we need the ids to be inside a particular range, so yeah an increasing counter. For example: For product A we have the range 202043200000000 to 202043210000000, so the generated numbers would be: 202043200000000 202043200000001 20204320000000…

I would probably have a look at erlang counters if I had to do the same task.

ty for the link, i’ll take a look

Do the counters / sequences need to be durable across BEAM restarts, or internally consistent across multiple BEAM nodes? Both of those are challenging with any of the ideas above. Some other questions that come to mind: Do they need to be monotonic across all machines? Are gaps permissible? Are …

In my company we had the exact problem you have and we solved it using Postgres advisory locks: PostgreSQL: Documentation: 9.4: Explicit Locking Point 13.3.5 So you don’t deal with the concurrency on your elixir application, but on the database level. So let’s say you want to have a sequential nu…

The counters should be durable and consistent. Having gaps is permissible but not ideal Collisions are a big problem Overflowing a range should not be an issue (range >>> sale volume) My first thought was using something like Postgres sequences, but then I thought that having it on application c…

@emoragaf I just had similar requirements pop up in my project and I’m wondering if you chose an application-oriented solution? I currently cluster my Elixir project using libcluster+swarm so I think I can pull this off in pure Elixir/Erlang using globally-named processes. But I’m not looking to re…

If you use a database like postgreSQL, you can use an auto-incremented sequence. The problem of using a OTP process is you will still need to serialize it in storage or you will start from 1 again once the cluster reboot. With serialization come with all the ACID problems, so you will be looking pr…

[image] derek-zhou: If you use a database like postgreSQL, you can use an auto-incremented sequence. This will not provide the properties that the OP wants. auto-incrementing sequences do not guarantee sequential ids in records. Sequences are non transactional, so if you open a transaction, i…

Elixir Programming Language Forum

Best way to generate sequential ids

Questions & Help Questions

derek-zhou May 24, 2021, 8:43pm 13

If the OP cannot tolerate occasional gaps then it is a hard problem indeed.