[#Blogged]Transient Keyword in Salesforce

Declaring variables as transient reduces view state size. A common use case for the transient keyword is a field on a Visualforce page that is needed only for the duration of a page request, but should not be part of the page's view state and would use too many system resources to be recomputed many times during a request.
The transient variables are not passed to view state and therefore not stored in View State.

difference between transient instance variable and a static variable?

Static methods, variables, or initialization code are associated with a class and are only allowed in outer classes.
When you declare a method or variable as static, it's initialized only once when a class is loaded. All static member variables in a class are initialized before any object of the class is created.  Indeed they aren't transmitted as part of the view state for a Visualforce page.
Using static variables will cause only one instance of the variable to be loaded when the application loads and that variable will not go out of memory until the app is closed.  It holds information that is common to all instances on a class and It is shared between them instead of being created a new with each instance.
while
Transient keyword to declare instance variable that can not be saved and should not be transmitted as part of view state for visual force page.
Basically, View State is an encrypted, hidden field on a Visualforce page that keeps track of Apex controller state & Visualforce page state between server requests. This field is only generated when there is a tag present on a page.

ViewState is only used on a single page that handles postbacks. Once you redirect to the new page, the ViewState is lost.

The Whole Process of Calling is like this :

A. URL Requested
B. Apex Controller Instantiated on Server
C. Controller State Serialized & Encrypted to View State
D. Page Markup Sent to Browser & Rendered
E. View State Decrypted & Deserialized (for Postbacks)

View State Automatically keeps track of field values for you and Allows for easy AJAX functionality. In order to remove View State Error, we use 4 methods.

A. Reduce Number of Components
B. Use the transient Keyword
C. Use JavaScript Remoting
D. Use the Streaming API

References: https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_classes_keywords_transient.htm

[#Blogged]Granular Locking in Salesforce

Granular Locking in Salesforce

The system employs additional logic to allow multiple updates to proceed simultaneously if there is no hierarchical or other relationship between the roles or groups involved.

For example: if you trying to edit the user details but on the other hand automated process is already doing that then you are not allowed to edit.

for this we use granular locking, this will not lock the entire table but only specific data.

What are the key advantages of granular locking?

1) Groups that are in separate hierarchies can be manipulated concurrently

2) Public groups and roles that do not include territories can be manipulated concurrently

3) Users can be added concurrently to territories and public groups

4) User provisioning can occur in parallel

5) A single-long running process, such as a role delete, only blocks a small subset of operations

Benefits to customers:

Customers who frequently experience locking that restricts their ability to manage manual and automated group maintenance operations.
Enable granular locking, which attempts to lock only the modified portions of the table. This can improve the performance of the following items:
1) Adding/deleting/transferring user from a territory
2) Re-parent a territory
3) Create or delete a territory within a hierarchy
4) Adding or removing a forecast manager

Check the below link for more information
https://resources.docs.salesforce.com/sfdc/pdf/draes.pdf

[#Blogged]Like operator in SOQL

Like operator in SOQL

 Like keyword is same as like in SQL. We can find/get the record utilizing this keyword. Expression is true if the value in the designated fieldname matches characters of text string in the designated value.

    

The LIKE operator in SOQL and SOSL is homogeneous to the LIKE operator in SQL; it provides a mechanism for matching partial text strings and includes support for wildcards.

    

* % and _ wildcards are fortified for LIKE operator.

    * % wildcard matches zero or more characters.

    * _ wildcard matches precisely one character.

    * Text string in the designated value must be enclosed in single quotes.

    * LIKE operator is fortified for string fields only.

    * LIKE operator performs a case-callous match, unlike the case-sensitive matching in SQL.

    * LIKE operator in SOQL and SOSL fortifies eluding of special characters % or _.

    * Do not utilize the backslash character in a search except to elude a character.

For example 

List listOfAccounts;
listOfAccounts = [SELECT id, Name
                           FROM Account
                           WHERE Name  LIKE '%test%'];
This query matches both testasish,accounttest, and test.

 SELECT AccountId, FirstName, lastname FROM Contact WHERE lastname LIKE 'AC_%'

Select id, email from contact where email like '%a' or email like '%x';