xuhang57

#!/bin/sh

# mysqldump -u[root] -p[root_password] [database_name] > [dbdump].sql
mysqladmin -u[root] -p[root_password] drop [database_name]
sudo systemctl stop mariadb
sudo rm /var/lib/mysql/ibdata1 
sudo rm /var/lib/mysql/ib_logfile*
sudo systemctl start mariadb
# mysqladmin -u[root] -p[root_password] create [database_name]
# mysqladmin -u[root] -p[root_password] [database_name] < [dbdump].sql

xuhang57

# Create a load balancer
openstack loadbalancer create --name lb1 --vip-subnet-id <SubnetName("public")>

# Create a listener
openstack loadbalancer listener create lb1 --protocol HTTP --protocol-port 80 --name listener1

# Create a pool
openstack loadbalancer pool create --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --name pool1

# Create a health monitor

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# create a flavor which would be used by the instance
openstack flavor create --id 0 --vcpus 1 --ram 2048 --disk 20 m1.small
#openstack flavor create --id 1 --vcpus 4 --ram 8192 --disk 80 m1.large
#openstack flavor create --id 2 --vcpus 8 --ram 16384 --disk 160 m1.xlarge

# create a network
openstack extension list -c Alias -c Name --network # list extensions within the system
openstack network create net1
#openstack network create net2 --provider-network-type vxlan
openstack subnet create subnet1 --network net1 --subnet-range 192.0.2.0/24

xuhang57

/* https://www.baeldung.com/java-stack-heap */
class Person {
    int pid;
    String name;
    // constructor, setter/getters
}

public class Driver {
    /**
      * 1. Upon entering the main() method, a space in stack memory would be created to store primitives

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/*
Using the synchronized keyword to protect blocks of code within a method.
This block is guarded by a key, which can be either a string or an object
This key is called the lock
*/


public synchronized void critial() {
    // some thread critical stuff
}

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# --------
# Hardware
# --------

# Opcode - operational code
# Assebly mnemonic - abbreviation for an operation

# Instruction Code Format (IA-32)
# - Optional instruction prefix
# - Operational code

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# String
string = ""

# Tuple
t = tuple() # (), (1,)

# List (Array)
l = []

# Stack, LIFO

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def quick_sort(arr):
    smaller, equal, greater = [], [], []
    
    if len(arr) > 1:
        pivot = arr[0]
        for x in arr:
            if x < pivot:
                smaller.append(x)
            elif x == pivot:
                equal.append(x)

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def selection_sort(arr):
    for i in range(len(arr)):
        min_idx = i
        for j in range(i+1, len(arr)):
            if arr[min_idx] > arr[j]:
                min_idx = j
                
        arr[i], arr[min_idx] = arr[min_idx], arr[i]
    
    return arr

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def insertion_sort(arr):
    for i in range(1, len(arr)):
        cur_val = arr[i]
        
        # indexes of the previous values
        j = i-1
        
        while j>=0 and cur_val < arr[j]:
            arr[j+1] = arr[j]
            j -= 1