disk | network disk | Incremental Backup library

You can get around the problems of subclassing dict by subclassing collections.UserDict instead. As the docs say:

Class that simulates a dictionary. The instance’s contents are kept in a regular dictionary, which is accessible via the data attribute of UserDict instances. If initialdata is provided, data is initialized with its contents; note that a reference to initialdata will not be kept, allowing it be used for other purposes.

Essentially, it's a thin regular-class wrapper around a dict. You should be able to use it with multiple inheritance as an abstract base class, as you do with AbstractRememberingDict.

Normally, I would do something with scipy.ndimage.morphology.distance_transform_edt but this gives the assume that isotropic sizes of the voxel:

It does no such thing! You are looking for the sampling= parameter. From the latest version of the docs:

Spacing of elements along each dimension. If a sequence, must be of length equal to the input rank; if a single number, this is used for all axes. If not specified, a grid spacing of unity is implied.

The wording "sampling" or "spacing" is probably a bit mysterious if you think of pixels as little squares/cubes, and that is probably why you missed it. In most situations, it is better to think of pixels as point samples on a grid, with fixed spacing between samples. I recommend Alvy Ray's a pixel is not a little square for a better understanding of this terminology.

Your problem is that you have set SESSION_CONNECTION=session, but your SESSION_DRIVER=default, so you have to use SESSION_DRIVER=database in your .env. See the config/session.php:

with the hope that due to the Retain policy, the new pods (i.e. their PVCs would bind to the existing PVs (and data wouldn't get lost)

It is explicitly written in the documentation that this is not what happens. the PVs are not available for another PVC after delete of a PVC.

the PersistentVolume still exists and the volume is considered "released". But it is not yet available for another claim because the previous claimant's data remains on the volume.

The problem seems to be in this line

You didn't describe omitting pg_replslot during your rsync, as the docs recommend. If you didn't omit it, then now your replica has a replication slot which is a clone of the one on the master. But if nothing ever connects to that slot on the replica and advances the cutoff, then the WAL never gets released to recycling. To fix you just need to shutdown the replica, remove that directory, restart it, (and wait for the next restart point to finish).

Do they need to go to wal_archive folder on the disk just like they go to wal_archive folder on the master node?

No, that is optional not necessary. It is set by archive_mode = always if you want it to happen.

I answer as I know things on each part, possibly disregarding a few of your assertions:

I have four questions. Suppose in spark I have 3 worker nodes. Each worker node has 3 executors and each executor has 3 cores. Each executor has 5 gb memory. (Total 6 executors, 27 cores and 15gb memory). What will happen if: >>> I would use 1 Executor, 1 Core. That is the generally accepted paradigm afaik.

• I have 30 data partitions. Each partition is of size 6 gb. Optimally, the number of partitions must be equal to number of cores, since each core executes one partition/task (One task per partition). Now in this case, how will each executor-core will process the partition since partition size is greater than the available executor memory? Note: I'm not calling cache() or persist(), it's simply that I'm applying some narrow transformations like map() and filter() on my rdd. >>> The number of partitions being the same of number of cores is not true. You can service 1000 partitions with 10 cores, processing one at a time. What if you have 100K partition and on-prem? Unlikely you will get 100K Executors. >>> Moving on and leaving Driver-side collect issues to one side: You may not have enough memory for a given operation on an Executor; Spark can spill to files to disk at the expense of speed of processing. However, the partition size should not exceed a maximum size, was beefed up some time ago. Using multi-core Executors failure can occur, i.e. OOM's, also a result of GC-issues, a difficult topic.

• Will spark automatically try to store the partitions on disk? (I'm not calling cache() or persist() but merely just transformations are happening after an action is called) >>> Not if it can avoid it, but when memory is tight, eviction / spilling to disk can and will occur, and in some cases re-computation from source or last checkpoint will occur.

• Since I have partitions (30) greater than the number of available cores (27) so at max, my cluster can process 27 partitions, what will happen to the remaining 3 partitions? Will they wait for the occupied cores to get freed? >>> They will be serviced by a free Executor at a point in time.

• If I'm calling persist() whose storage level is set to MEMORY_AND_DISK, then if partition size is greater than memory, it will spill data to the disk? On which disk this data will be stored? The worker node's external HDD? >>> Yes, and it will be spilled to the local file system. I think you can configure for HDFS via a setting, but local disks are faster.

This an insightful blog: https://medium.com/swlh/spark-oom-error-closeup-462c7a01709d

This was a bug of the SDK, now fixed (server-side, so doesn't require a library update).

The block of code in the question is the correct way for increasing ephemeral storage via the Ruby SDK:

Your guess is correct. The createHeapSnapshot() returns a promise, but that promise has NO connection at all to when the stream is done. Therefore, when the caller uses await on that promise, the promise is resolved long before the stream is actually done. async functions have no magic in them to somehow know when a non-promisified asynchronous operation like .pipe() is done. So, your async function returns a promise that has no connection at all to the stream functions.

Since streams don't have very much native support for promises, you can manually promisify the completion and errors of the streams: