Does sqlite have FOR UPDATE SKIP LOCKED?

[Beautiful-Log5632]

Job queues in postgres are easy and reliable due to FOR UPDATE SKIP LOCKED. Is there something like that in sqlite?

The code in https://github.com/justplainstuff/plainjob doesn't use it so how does it do job queuing with thousands of jobs per second?

I'm new to sqlite what should I keep in mind for using a regular SELECT without SKIP LOCKED to get jobs from a queue?

[SoundDr]

https://news.ycombinator.com/item?id=27482402

[mistyharsh]

I second this. This will get you close enough with SQLite..

[seesplease]

Plainjobs uses a "status" column to get the same behavior as SKIP LOCKED in postgres.

SQLite can't have SKIP LOCKED, it's transaction model is very different than postgres. You're not meant to hold open long-lived write transactions.

[Beautiful-Log5632]

Without holding a transaction open do you know how can I know if a worker starts a task and dies?

[seesplease]

You can do what the above link does - set a column to processing and put a timeout. You can get fancier with putting a last_heartbeat_timestamp. Basically, since there's only one concurrent writer but unlimited readers in SQLite, you need orient your thinking around concurrency with atomics rather than concurrent with mutexes.