standby | Read from standby databases for ActiveRecord | Database library

Yes, Doze will ignore your wakelock. However with setExactAndAllowWhile Idle you will be worken up at the correct time, and you'll have that 10s window to do any processing you wish.

I must add that this approach does not look very secure to me.

You cannot use tables (even temporary ones) on a standby server. I think the easiest way to approach this is to write a PL/PerlU or PL/PythonU to do the necessary file modifications. You also have to call the function pg_reload_comf() to activate the modifications.

Following should work.

I assume you're talking about the Readable Standby Instances available in Preview at the time of writing this.

Compared to the traditional read replicas, the main difference is the kind of replication involved. Replication to read replicas happens asynchronously. That means read replicas aren't necessarily up to date with the main database. This is something your workload needs to be able to deal with if you want to use that.

Readable standby instances on the other hand use synchronous replication. When you read from one of those instances your data will be up to date.

There are also a couple of other differences between the capabilities, but some things aren't finalised yet. The main difference is the kind of replication.

Multi-AZ is backup only within same region. It does not protect you from data loss caused by entire region outage or destruction.

For mission critical databases you can either create read replica in a different region for live backups, or a cheaper solution is to copy db snapshots to different region on periodic basis.

Generally speaking, ActiveMQ Artemis is notably faster than ActiveMQ "Classic" due to the significant architectural differences between them. In short, ActiveMQ Artemis was designed to be completely non-blocking and performs very well at scale compared to ActiveMQ "Classic".

However, in this case you are not testing the brokers at scale. You are testing one producer and a "different number" of consumers. This is certainly not the kind of production use-case that would warrant a cluster of 3 brokers. A single broker on modest or even minimal hardware would almost certainly suffice.

Even if you push the client count to around 50 I still think one live node would suffice. You definitely want to use just one live node if you're using message grouping. See the documentation for important details about clustered message grouping.

It's also important to keep in mind that you must compare "apples to apples" in terms of each broker's configuration. This is not necessarily trivial, especially when dealing with clusters. You did not share your broker configurations so I can't comment on whether or not they are functionally equivalent or at least as close to functionally equivalent as possible. There are many different configuration-specific reasons why one broker might perform better than the other in certain use-cases.

Over the last several years SoftwareMill has published benchmarks for popular message brokers for the persistent, replicated queue use-case. The last time both ActiveMQ "Classic" and Artemis were tested was in 2017. Here are the results. Since then SoftwareMill no longer tests ActiveMQ "Classic".

You can preserve or not - it is usually (depending on the mode) up to the programmer. Memory consumes power so very often it is more energy efficient to reinitialize RAM after wake up (I do it sometimes in my projects)

Example: STM32L476:

The ThreadPool.SetMinThreads sets the minimum number of threads that the ThreadPool creates instantly on demand. That's the key phrase, and it is indeed quite unintuitive. The ThreadPool currently¹ (.NET 5) works in two modes:

1. When a new request for work arrives, and all the threads in the pool are busy, create instantly a new thread in order to satisfy the request.

2. When a new request for work arrives, and all the threads in the pool are busy, queue the request, and wait for 1 sec before creating a new thread, hoping that in the meantime one of the worker threads will complete its current work, and will become available for serving the queued request.

The ThreadPool.SetMinThreads sets the threshold between these two modes. It does not give you control over the number of threads that are alive right now. Which is not very satisfying, but it is what it is. If you want to force the ThreadPool to create 1,000 threads instantly, you must also sent an equal number of requests for work, additionally to calling ThreadPool.SetMinThreads(1000, 1000). Something like this should do the trick:

While LoRa SX1278 in sleep mode it will return 0x3, without showing 3MSB. However in the Standby Mode it reads 0x23 as it suppose to be.