jarek-przygodzki

# Installation

$ dnf -y install sysstat
$ systemctl enable --now sysstat

# create a new config to override the default 10 minutes
$ systemctl edit sysstat-collect.timer


[Unit]

jarek-przygodzki

I've recently looked into how core.longpaths Git options works and how it's related to Enable Win32 long paths Windows option. Turns out they are not related, and longpaths is both clever and hacky.

Many Windows wide char APIs support longer than MAX_PATH paths through the file namespace prefix (\\?\ or \\?\UNC\) followed by an absolute path. When long paths support is enabled via 'core.longpaths' option, handle_long_path function expands long paths using the '\?' file namespace prefix. See this commit message for detailed explantion.

jarek-przygodzki

jinfo

jinfo -flag MaxMetaspaceSize <pid>

 jinfo -flag MaxMetaspaceSize 25244
-XX:MaxMetaspaceSize=1073741824 # 1073741824 = 1GiB

jcmd

jarek-przygodzki

Fibers

Fibers are an abstraction over sequential computation, similar to threads but at a higher level. There are two ways to think about this model: by example, and abstractly from first principles. We'll start with the example.

(credit here is very much due to Fabio Labella, who's incredible Scala World talk describes these ideas far better than I can)

Callback Sequentialization

Consider the following three functions

jarek-przygodzki

                   <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-antrun-plugin</artifactId>
                        <configuration>
                            <tasks>
                                <sleep seconds="10" />
                            </tasks>
                        </configuration>
                        <executions>
                            <execution>

jarek-przygodzki

# Explicit proxy server
Get-ItemProperty -Path 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings' | Select-Object ProxyServer
# In case of proxy auto-config you can get the PAC file URL in registry
Get-ItemProperty -Path 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings\AutoConfigURL'

jarek-przygodzki

In elevated command prompt (Win+X)

Check status (look for HibernateEnabled: 0 means off, 1 means on)
> Get-ItemProperty HKLM:\SYSTEM\CurrentControlSet\Control\Power -name HibernateEnabled
or
> reg query "HKLM\SYSTEM\CurrentControlSet\Control\Power" /v "HibernateEnabled"

Enable
> powercfg -h 
or 

jarek-przygodzki

jarekprzygodzki@Jareks-MacBook-Pro ~ % /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

==> This script will install:
/usr/local/bin/brew
/usr/local/share/doc/homebrew
/usr/local/share/man/man1/brew.1
/usr/local/share/zsh/site-functions/_brew
/usr/local/etc/bash_completion.d/brew
/usr/local/Homebrew
==> The following existing directories will be made group writable:

jarek-przygodzki

import lombok.val;
import org.junit.Assert;
import org.junit.Test;

import java.lang.invoke.*;

/*
Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.

Please don't actually do this... :P

jarek-przygodzki

Download ZIP file from https://www.enterprisedb.com/download-postgresql-binaries
Unpack to any directory of your choosing (C:\bin\pgsql)

PS C:\bin\pgsql> $env:PGDATA = "C:\bin\pgsql\data"
PS C:\bin\pgsql> .\bin\initdb "--username=postgres"
# postgres.exe vs pg_ctl.exe: see https://www.postgresql.org/docs/current/server-start.html 
PS C:\bin\pgsql> .\bin\postgres.exe