Hacker News: isignal

New comment by isignal in "Shopify replaced Redis with MySQL for inventory reservations–and it scaled"

isignal — Sun, 09 Aug 2026 03:18:56 +0000

Two concurrent deductions of inventory do contend but only during the actual DB update. That is just normal DB locking for SQL isolation levels. The blog refers to explicit locking by the app, which is where skip locked comes in.

New comment by isignal in "Shopify replaced Redis with MySQL for inventory reservations–and it scaled"

isignal — Sun, 09 Aug 2026 03:16:21 +0000

Yes, at a high level. It doesn't rely on skip locked, which is not cheap at DB level. DB has to still typically run query and keep going until it finds an unlocked item. Deducting and checking inventory counts are simpler ops inside the DB.

New comment by isignal in "Shopify replaced Redis with MySQL for inventory reservations–and it scaled"

isignal — Sun, 09 Aug 2026 02:16:30 +0000

It seems there could be a simpler solution.

1. Deduct the reservation from the inventory when the user starts to order, but in the same txn also maintain a separate row for the in progress order flow. 2. If the order flow is aborted or times out have a background process that returns these to the inventory.

That seems simpler than this approach and involves no locking. Though their presented approach is also reasonable, there must be some reason not to choose a simpler flow. It is not that difficult to have a gc service that scales, but may be they didn't want to separate that.

New comment by isignal in "Trumpcard (Official US Government Website)"

isignal — Sat, 20 Sep 2025 17:32:22 +0000

The EB5 visa, by comparison, has much more clear requirements. It is not sure if this intended as a backdoor to EB5 or a replacement.

New comment by isignal in "Trumpcard (Official US Government Website)"

isignal — Sat, 20 Sep 2025 17:31:32 +0000

There already was such a system with more concrete requirements. It is called the EB5 visa and has a path to green card. What does this new method bring to the table?

New comment by isignal in "The first year of free-threaded Python"

isignal — Fri, 16 May 2025 15:30:45 +0000

Processes can die independently so the state of a concurrent shared memory data structure when a process dies while modifying this under a lock can be difficult to manage. Postgres which uses shared memory data structures can sometimes need to kill all its backend processes because it cannot fully recover from such a state.

In contrast, no one thinks about what happens if a thread dies independently because the failure mode is joint.

New comment by isignal in "Databricks acquires Neon"

isignal — Thu, 15 May 2025 03:25:13 +0000

Thanks for the pointers!

New comment by isignal in "Databricks acquires Neon"

isignal — Wed, 14 May 2025 15:38:01 +0000

Aren't the alternatives you mentioned - icerberg and duckdb - both storage solutions while spark is a way to express distributed compute? I'm a bit out of touch with this space, is there a newer way to express distributed compute?

New comment by isignal in "Wyze pays $255k of tariffs on $167k of floodlights"

isignal — Thu, 01 May 2025 15:25:04 +0000

https://www.patentlyapple.com/2024/04/apple-now-makes-14-of-...

You are incorrect.

> Apple Inc has assembled $14 billion worth of iPhones in India in fiscal 2024, Bloomberg News reported on Wednesday.

New comment by isignal in "Microsoft open sources PostgreSQL extensions to muscle in on NoSQL"

isignal — Tue, 11 Feb 2025 16:28:52 +0000

Postgres supports indexing an arbitrary json document. https://www.postgresql.org/docs/current/datatype-json.html

Not sure if the query capabilities and syntax match azure docdb but the basic functionality should be workable.

New comment by isignal in "Every System is a Log: Avoiding coordination in distributed applications"

isignal — Fri, 24 Jan 2025 22:03:14 +0000

The transaction log maintained from time 0 would be equivalent but too expensive to store compared to the tables.

New comment by isignal in "The Toyota Prius transformed the auto industry"

isignal — Sat, 18 Jan 2025 15:23:38 +0000

Resale values are lower in US because they factor in the 7.5k USD tax credit and the state tax credit mostly, there is plenty of demand for used teslas for example.

New comment by isignal in "Canvas is a new way to write and code with ChatGPT"

isignal — Thu, 03 Oct 2024 18:28:31 +0000

Consumer side can allow you to run ads and get Google like revenue in the future.

New comment by isignal in "Intel's Humbling"

isignal — Wed, 31 Jan 2024 04:26:50 +0000

Intel also had a later chance when Apple tried to get off the Qualcomm percent per handset model. This was far after the original iPhone. Apple also got sued for allegedly sharing proprietary Qualcomm trade secrets with Intel. And Intel still couldn’t pull it off despite all these tailwinds.

New comment by isignal in "Updates on Grounding of Boeing 737 MAX 9 Aircraft"

isignal — Sat, 13 Jan 2024 16:30:11 +0000

Are they cheekily quoting the CEO who made a similar statement last week?

New comment by isignal in "Systemd through the eyes of a musl distribution maintainer"

isignal — Sat, 06 Jan 2024 18:07:18 +0000

Just a note that this requires the admin to enable linger if the units need to be started before the user logs in and run after they logout.

New comment by isignal in "Amazon's Silent Sacking"

isignal — Sun, 31 Dec 2023 05:36:34 +0000

Microsoft, Facebook, google, Apple, Amazon etc are all hugely profitable companies. If anyone can afford to ride out wall streets short term thinking, it is them.

New comment by isignal in "S3 Express One Zone, not quite what I hoped for"

isignal — Sun, 17 Dec 2023 06:30:58 +0000

For a key value store you expect server side latencies less than 5 ms for point gets and writes.

New comment by isignal in "'Greedflation' study finds many companies were lying to you about inflation"

isignal — Sat, 09 Dec 2023 16:55:21 +0000

Even if wages did catch up, retired folks are permanently disadvantaged. There’s a reason why the Fed targets a low inflation rate by default than letting it float freely.

New comment by isignal in "One sleepless night can rapidly reverse depression for several days in mice"

isignal — Fri, 03 Nov 2023 05:37:29 +0000

Body scan meditation is one particular form of meditation that I’ve found effective for sleep.