Race Data

1. Introduction

1.1 What is RaceData

    + Firstly, I would like to say for you RaceData difference RaceCondition. This course will tall about RaceData. RaceCondition will disscuss at another

    + What is RaceData: When multiple process are called to process and they use same CriticalRegion so can process1, process2 or ... processN get CriticalRegion but that's not last value.

        Exp: Your account has balace $100.000

            + Step1: You open Chrome browser and login on it, and you open Transfer form to accountA with $100.000.

            + Step2: You open Firefox browser and login on it, and you open Transfer form to accountA with $100.000 same.

            + Step3: You will make money transfers at the same time from both browers above.

            + Step4: Go to accountA and check balance, wowww, supprise if lucky you will get $200.000

            => That's RaceData

1.2 Preventing RaceData

2. Directory Struct

Root

|__data

|   |__employee.json -- example data

|

|__src

|   |__MatualExclusion -- this class prevent RaceData

|       |__MatualExclusion.php

|       |__SumMatualExclusion.php

|

|__composer.json - package dependency

|__index.php - Run to test update: adding 50.000 into employee.json/amount after each run

|

|__index1.php

|__index2.php - Run index1.php & index2.php at the same time to see RaceData issue

|

|__index3.php

|__index4.php - Run index3.php & index4.php at the same time to see you won't been RaceData issue

3. Step by step do it

3.1 Clone/download RaceData folder to your computer

    3.1.1 Download from browser

        3.1.1.1 Goto RaceData folder > D:\YourFolder\RaceData

        3.1.1.2 Run composer: composer install

        3.1.1.3 Open D:\YourFolder\RaceData\data\employee.json

            {"id":10,"name":"TrueMe","amount":1000.000}

        3.1.1.4 Run for test D:\YourFolder\RaceData\index.php

            + First: you will see

                D:\Projects\test\RaceData\index.php:6:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1000000

                D:\Projects\test\RaceData\index.php:13:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1050000

            + Second: you will see

                D:\Projects\test\RaceData\index.php:6:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1050000

                D:\Projects\test\RaceData\index.php:13:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1100000

            + Last amount: 1.100.000

        3.1.1.5 Run for test D:\YourFolder\RaceData\index1.php && index2.php at the same time

            + index1.php

                D:\Projects\test\RaceData\index1.php:8:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1100000

                D:\Projects\test\RaceData\index1.php:16:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1150000

            + index2.php

                D:\Projects\test\RaceData\index2.php:8:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1100000

                D:\Projects\test\RaceData\index2.php:16:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1150000

            + Last amount: 1.150.000 => wrong value. Because of 1.200.000 is expected value

        3.1.1.6 Run for test D:\YourFolder\RaceData\index3.php && index4.php at the same time

            + index3.php

                D:\Projects\test\RaceData\index3.php:11:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1150000

                D:\Projects\test\RaceData\index3.php:21:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1200000

            + index4.php

                D:\Projects\test\RaceData\index4.php:11:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1150000

                D:\Projects\test\RaceData\index4.php:20:

                array (size=3)

                  'id' => int 10

                  'name' => string 'TrueMe' (length=6)

                  'amount' => int 1250000

            + Last amount: 1.250.000 => this is expected value, when you use index3.php && index4.php so that prevent RaceData