- Don’t
SELECT *
, Specify explicit column names (columnar store) - Avoid large JOINs (filter each table first)
- In PRESTO tables are joined in the order they are listed!!
- Join small tables earlier in the plan and leave larger fact tables to the end
- Avoid cross joins or 1 to many joins as these can degrade performance
- Order by and group by take time
- only use order by in subqueries if it is really necessary
- When using GROUP BY, order the columns by the highest cardinality (that is, most number of unique values) to the lowest.
function _cdk_completer { | |
STACK_CMDS="list synthesize bootstrap deploy destroy diff metadata init context docs doctor" | |
if [ "$3" == "cdk" ]; then | |
COMPREPLY=($(compgen -W "$STACK_CMDS" $2)) | |
elif [[ -d "cdk.out" ]] && ! [[ "$2" == "-"* ]]; then | |
TEMPLATES=$(ls -1 cdk.out/*.template.json | awk '{split($0,t,/\/|\./); print t[3]}') | |
COMPREPLY=($(compgen -W "$TEMPLATES" $2)) | |
else | |
COMPREPLY=() |
import autoscaling = require("@aws-cdk/aws-autoscaling") | |
import scriptAssets = require("./CfnInitScriptAsset") | |
import iam = require('@aws-cdk/aws-iam') | |
import cdk = require('@aws-cdk/core') | |
/** | |
* Helpful context into what was built. | |
* Use these to get logical ID's when constructing your userdata. | |
*/ |
a4b.amazonaws.com | |
access-analyzer.amazonaws.com | |
account.amazonaws.com | |
acm-pca.amazonaws.com | |
acm.amazonaws.com | |
airflow-env.amazonaws.com | |
airflow.amazonaws.com | |
alexa-appkit.amazon.com | |
alexa-connectedhome.amazon.com | |
amazonmq.amazonaws.com |
Frequently, our EMR applications need to perform cross-account read/write, i.e., the cluster is created under one AWS billing account, but the data lives under another (let's call it "guest account"). Because security concerns, we cannot grant blank S3 access to the guest account. Instead, we should rely on assume-role function of AWS STS to provide ephemeral authentication for read/write transactions. The basic logic for calling STS service is not difficult, but there are some pitfalls when you want to integrate the assume-role authentication with EMRFS.
For hadoop/Spark, the authentication process is handled within the file system itself, so the application code can write to a S3 file without worrying about the underlying nitty-gritty details. EMRFS is an implementation o
FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.
- By Edmond Lau
- Highly Recommended 👍
- http://www.theeffectiveengineer.com/
#!/usr/bin/python | |
# -*- coding: utf-8 -*- | |
import pprint | |
import subprocess | |
def get_processes(): | |
""" | |
Parse the output of `ps aux` into a list of dictionaries representing the parsed |
This page documents the external/internal behavior of Casper.
Casper installed itself into the following directories:
- /Library/Application Support/JAMF
- ManagementFrameworkScripts - a set of scripts that runs on certain events
- StartupScript.sh - Activated when jamf is started
- loginhook.sh - Activated when user login
- ManagementFrameworkScripts - a set of scripts that runs on certain events
- logouthook.sh - Activated when user logout