ToanPV90

1. I see that most of your connections and queries are running on the master(writer) database instance itself without much load on the reader instance. You can consider dividing your workload such that read-only queries/workloads are directed to the reader instance, and only write queries are handled by your writer instance. This will help alleviate the large undo logs(RollbackSegmentHistoryListLength) due to long running queries and in itself this should mitigate a lot of the performance issues. 

	One way to achieve splitting of Reads and Writes is by making use of a third party software Proxy solution which can split reads and writes to the appropriate endpoints. Below are a few example software solutions which you can consider:
	[+] ProxySQL - https://proxysql.com/ 
	[+] Heimdall Data - https://www.heimdalldata.com/ 
    
    
2. If and where possible, try to split large transactions into multiple smaller transactions. This will again reduce the growth of the undo log which seems to be the main cause of t

ToanPV90

import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;

ToanPV90

This recipe is a work in progress and has never been run as-is.

• timeouts are in ms
• lock timeout: in postgres, when a statement that wants a restrictive lock waits on another lock, other statements that want locks can't jump the queue. so even though the statement that is waiting might only take a very short amount of time, when it starts running, while it is waiting no other statements can begin. So we set the lock timeout pretty low and retry if we don't get it.
• statement timeout: we set a short statement timeout before statements which do lock and which we expect to take a short amount of time, just in case something about our assumptions/understanding is wrong and the statement ends up taking a long time. if this happens the statement will bail early without causing harm, and we can investigate what is wrong with

ToanPV90

Multiple SSH Keys settings for different github account

create different public key

create different ssh key according the article Mac Set-Up Git

$ ssh-keygen -t rsa -C "[email protected]"

ToanPV90

font Menlo for Powerline Terminal VS code

git clone https://github.com/abertsch/Menlo-for-Powerline.git

sudo mv Menlo*.tff /usr/share/fonts

ToanPV90

It's Varargs :)

The varargs short for variable-length arguments is a feature that allows the method to accept variable number of arguments (zero or more). With varargs it has become simple to create methods that need to take a variable number of arguments. The feature of variable argument has been added in Java 5.

Syntax of varargs

A vararg is secified by three ellipsis (three dots) after the data type, its general form is

return_type method_name(data_type ... variableName){
}  

ToanPV90

List images
  $ docker images -a
  
Run container with mapping port
  $ docker run -d -p {localhost-port}:{container-port} image_name

Removing images according to a pattern
  $ docker images -a | grep "pattern" | awk '{print $3}' | xargs docker rmi -f
  
Removing all images

ToanPV90

#!/bin/bash
sudo add-apt-repository -y ppa:git-core/ppa
sudo apt-get update
sudo apt-get install git -y

ToanPV90

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

ToanPV90

package cm.flashbusiness.core.util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.joda.time.DateTime;

/**
 * @author dassi