| # Docker image for PostgreSQL with the TimescaleDB extensions installed, running on a Debian Stretch-Slim base | |
| # Begin by building TimescaleDB | |
| FROM postgres:11.2 AS build | |
| ENV TIMESCALEDB_VERSION 1.2.2 | |
| ENV TIMESCALEDB_SHASUM="c8e8071c24707e3fa8a50abb788c85d03a1bd9d9dea2e273b4abf407f39c182a timescaledb-${TIMESCALEDB_VERSION}.tar.gz" | |
| RUN buildDeps="curl build-essential ca-certificates git python gnupg libc++-dev libc++abi-dev pkg-config glib2.0 cmake libssl-dev" \ | |
| && apt-get update \ |
| CREATE SEQUENCE public.global_id_seq; | |
| ALTER SEQUENCE public.global_id_seq OWNER TO postgres; | |
| CREATE OR REPLACE FUNCTION public.id_generator() | |
| RETURNS bigint | |
| LANGUAGE 'plpgsql' | |
| AS $BODY$ | |
| DECLARE | |
| our_epoch bigint := 1314220021721; | |
| seq_id bigint; |
When using the alpine docker image, the command locale -a or locale-gen does not exist. You might need them to install different locales in your docker image to allow your applications to support multilingual. Most common issue is when dealing with database inputs (MySQL), whereby the text will be displayed as garbage characters if you do not have the right locale installed.
FROM alpine:3.6
# ---not shown here---
By default older Mac computer models have driver issues with the Broadcom Wi-Fi chip. Most instructions online (such as this one from the official Ubuntu docs @ https://help.ubuntu.com/community/Macmini5-1/Precise) suggest to use sudo apt-get and install these packages from the PPA.
BUT you don't have Internet so you can't use apt-get! Instead you can use a different computer to download the packages, then transfer them over.
In the instructions below, you will need to replace sid in the download URL's with the proper version of Debian your version of Ubuntu/Linux is using. To find which version you should use, you can view the chart at https://askubuntu.com/questions/445487/what-debian-version-are-the-different-ubuntu-versions-based-on#445496. If you're using jessie for example, then replace all sid with jessie in the links below.
b43-fwcutter @ (*Hugepages are a hardware feature designed to reduce pressure on the translation lookaside buffer (TLB) for applications that operate on large contiguous memory regions.
Take a program that operates on a large 2MB internal structure as an example. If the program accesses that space in such a way that one byte in each regular 4k page is accessed, 2M/4k = 512 TLB entries are needed. Each TLB miss at the hardware level requires and interrupt and kernel intervention to resolve. However, if the allocation is backed by a 2M hugepage by mmap()ing with MAP_HUGETLB, only 1 TLB entry is required.
On x86_64, there are two hugepage sizes: 2MB and 1G. 1G hugepages are also called gigantic pages. 1G must be enabled on kernel boot line with hugepagesz=1G. Hugeages, especially 1G ones, should to be allocated early before memory fragments (i.e. at/near boot time) to increase the likelihood that they can be allocated successfully with minimal memory migration (i.e. defreg) required
| Backup: | |
| docker exec -t -u postgres your-db-container pg_dumpall -c > dump_`date +%d-%m-%Y"_"%H_%M_%S`.sql | |
| Restore: | |
| cat your_dump.sql | docker exec -i your-db-container psql -Upostgres |
by Bjørn Friese
Beautiful is better than ugly. Explicit is better than implicit.
I frequently deal with collections of things in the programs I write. Collections of droids, jedis, planets, lightsabers, starfighters, etc. When programming in Python, these collections of things are usually represented as lists, sets and dictionaries. Oftentimes, what I want to do with collections is to transform them in various ways. Comprehensions is a powerful syntax for doing just that. I use them extensively, and it's one of the things that keep me coming back to Python. Let me show you a few examples of the incredible usefulness of comprehensions.
| # This is just a cheat sheet: | |
| # On production | |
| sudo -u postgres pg_dump database | gzip -9 > database.sql.gz | |
| # On local | |
| scp -C production:~/database.sql.gz | |
| dropdb database && createdb database | |
| gunzip < database.sql.gz | psql database |
| # PostgreSQL can be on a remote server but you'll need root privileges in Linux and superuser in PostgreSQL. | |
| # First install build tools | |
| sudo su | |
| aptitude install build-essential | |
| aptitude install postgresql-server-dev-9.4 | |
| # Clone and build the PL/pgSQL server-side debugger |
##Sass Functions Cheat Sheet
