| require "digest" | |
| require "rack" | |
| # This class encapsulates a unit of work done for a particular tenant, connected to that tenant's database. | |
| # ActiveRecord makes it _very_ hard to do in a simple manner and clever stuff is required, but it is knowable. | |
| # | |
| # What this class provides is a "misuse" of the database "roles" of ActiveRecord to have a role per tenant. | |
| # If all the tenants are predefined, it can be done roughly so: | |
| # | |
| # ActiveRecord::Base.legacy_connection_handling = false if ActiveRecord::Base.respond_to?(:legacy_connection_handling) |
You can take the same source code package that Ubuntu uses to build jq, compile it again, and realize 90% better performance.
I use jq for processing GeoJSON files and other open data offered in JSON format. Today I am working with a 500MB GeoJSON file that contains the Alameda County Assessor's parcel map. I want to run a query that prints the city for every parcel worth more than a threshold amount. The program is
| import { LiveViewHook } from './live_view_hook' | |
| /* | |
| * Tracks height of an element when viewport resizes and sets a variable accordingly. | |
| * | |
| * Used to set the header offset. | |
| */ | |
| class HeightTrackerHook extends LiveViewHook { | |
| private resizeObserver: ResizeObserver | null = null |
This study focuses on the strategies used by the "xz backdoor", an extremely
complex piece of malware that contains its own x64 disassembler inside of it
to find critical locations in your code and hijacks it by swapping out your
code with its own as it runs. Because this a machine-code based attack,
all code written in any program language can be attacked and is vulnerable.
Instead of targeting sshd directly, the xz
backdoor injects itself in the parent systemd process then hijacks the
GNU Dynamic Linker (ld), before sshd is even started or libcrypto.so is
| #!/bin/sh -- | |
| # \ | |
| exec jq -nsRrf --args -- "$0" "$@" | |
| def path2gronpath: | |
| reduce .[] as $k ("json"; . + ($k | | |
| if type == "number" or . == "" or test("^[0-9]|[^0-9a-zA-Z_]") | |
| then @json "[\(.)]" | |
| else ".\(.)" | |
| end)); |
By default Linux distros are unoptimized in terms of I/O latency. So, here are some tips to improve that.
Most apps still don't do multi-threaded I/O access, so it's a thread-per-app which makes per-app speed always bottlenecked by single-core CPU performance (that's not even accounting for stuttering on contention between multiple processes), so even with NVMe capable of 3-6 GB/s of linear read you may get only 1-2 GB/s with ideal settings and 50-150/100-400 MB/s of un/buffered random read (what apps actually use in real life) is the best you can hope for.
All writes are heavily buffered on 3 layers (OS' RAM cache, device's RAM cache, device's SLC-like on-NAND cache), so it's difficult to get real or stable numbers but writes are largelly irrelevant for system's responsiveness, so they may be sacrificed for better random reads.
The performance can be checked by:
| defmodule MyAppyWeb.TaskTestLive.Index do | |
| use MyAppWeb, :live_view | |
| require Logger | |
| @impl true | |
| def mount(_params, _session, socket) do | |
| # Trap exits to catch when a Task is forcibly cancelled. | |
| Process.flag(:trap_exit, true) | |
| socket = |
You also might wanna just use Whisky which does this automatically
This guide works on macOS 13.4+ using Command Line Tools for XCode 15 Beta!
In the recent WWDC, Apple announced and released the "game porting toolkit", which upon further inspection this is just a modified version of CrossOver's fork of wine which is a "compatibility layer" that allows you to run Windows applications on macOS and Linux.
