Elastic Search basic

 1. Node contains data as document

2. one cluster contains multiple nodes.

3. the document contains data as json format.

3. multiple documents group together to make indices.

• Replication is about maintaining real-time copies (primary and replica shards) of data within a cluster to ensure high availability, fault tolerance, and improved read performance.

• Snapshot is about creating backups of your data and settings at a specific point in time. Snapshots are useful for disaster recovery, migration, and long-term data retention.

Invertes index- > for text search

keyword: sorting or aggregation

 "name" : {

                  "type" : "text",

                  "fields" : {

                    "keyword" : {

                      "type" : "keyword",

                      "ignore_above" : 256

                    }

                  }

                }

so this name field will store in inverted index as well in doc_value also up to 256 char

  "type" : "text", -> store in innverted index

using below store in doc value as well that will use for sort and aggregation.

"keyword" : {

                      "type" : "keyword",

                      "ignore_above" : 256

                    }

Logstash

 Logstash is a Data pipeline it consist of three stages inputs, filters and outputs.

input-> can get data from Kafka,relation database , file or any other input source or can get data from multiple input source also.

filters -> filter what kind of data we need to process. 

outlet -> where we need to write data after filter like elastic

Take an example we want to read logs of access.log from file using logstash

like log stash receive one line of log -> then process line using grok pattern then push into elastic .

Having too many concurrent indexing connections may result in a high bulk queue, bad responsiveness and timeouts. And for that reason in most cases, the common setup is to have Logstash placed between Beat instances and Elasticsearch to control the indexing.

And for larger scale system, the common setup is having a buffering message queue (Apache Kafka, Rabbit MQ or Redis) between Beats and Logstash for resilency to avoid congestion on Logstash during event spikes.

t

mvn for Sonar

 mvn sonar:sonar -Dsonar.login=developer -Dsonar.password=developer

Trigger in Mysql

create table employee (id INT AUTO_INCREMENT PRIMARY KEY, name varchar(255), employeeNumber varchar(255), createdDate datetime);

create table employee_audit (id INT AUTO_INCREMENT PRIMARY KEY,employee_id int,  name varchar(255), employeeNumber varchar(255), createdDate datetime,audit_created_date datetime);

Trigger:

delimiter //

create TRIGGER employee_update After update on employee  for each row  begin  insert into employee_audit (employee_id,name,employeeNumber,createdDate,audit_created_date) values (OLD.id,OLD.name,OLD.employeeNumber,OLD.createdDate,sysdate());  end;//

delimiter ;

in above statement we can see delimiter // this is used to change the delimiter ; to // we need to change delimiter because we are using multiple ; in trigger so after changing delimiter we can use // to break the statement

insert into employee (name,employeeNumber,createddate) values('sushil','001',sysdate);

update employee set name = 'sushil mittal' where id = 1;

//after update new entry get created in employee_audit table with exist record

we can add condition in trigger also like:

if we want to audit only if empployeeNumber get updated

 IF :OLD.employeeNumber != :NEW.employeeNumber THEN

delimiter //

create TRIGGER employee_update After update on employee  for each row  begin 

 IF :OLD.employeeNumber != :NEW.employeeNumber THEN

 insert into employee_audit (employee_id,name,employeeNumber,createdDate,audit_created_date) values (OLD.id,OLD.name,OLD.employeeNumber,OLD.createdDate,sysdate());  end;//

delimiter ;

LeetCode 75 problems

 

Array

• Two Sum
• Best Time to Buy and Sell Stock
• Contains Duplicate
• Product of Array Except Self
• Maximum Subarray
• Maximum Product Subarray
• Find Minimum in Rotated Sorted Array
• Search in Rotated Sorted Array
• 3 Sum
• Container With Most Water

---

Binary

• Sum of Two Integers
• Number of 1 Bits
• Counting Bits
• Missing Number
• Reverse Bits

---

Dynamic Programming

• Climbing Stairs
• Coin Change
• Longest Increasing Subsequence
• Longest Common Subsequence
• Word Break Problem
• Combination Sum
• House Robber
• House Robber II
• Decode Ways
• Unique Paths
• Jump Game

---

Graph

• Clone Graph
• Course Schedule
• Pacific Atlantic Water Flow
• Number of Islands
• Longest Consecutive Sequence
• Alien Dictionary (Leetcode Premium)
• Graph Valid Tree (Leetcode Premium)
• Number of Connected Components in an Undirected Graph (Leetcode Premium)

---

Interval

• Insert Interval
• Merge Intervals
• Non-overlapping Intervals
• Meeting Rooms (Leetcode Premium)
• Meeting Rooms II (Leetcode Premium)

---

Linked List

• Reverse a Linked List
• Detect Cycle in a Linked List
• Merge Two Sorted Lists
• Merge K Sorted Lists
• Remove Nth Node From End Of List
• Reorder List

---

Matrix

• Set Matrix Zeroes
• Spiral Matrix
• Rotate Image
• Word Search

---

String

• Longest Substring Without Repeating Characters
• Longest Repeating Character Replacement
• Minimum Window Substring
• Valid Anagram
• Group Anagrams
• Valid Parentheses
• Valid Palindrome
• Longest Palindromic Substring
• Palindromic Substrings
• Encode and Decode Strings (Leetcode Premium)

---

Tree

• Maximum Depth of Binary Tree
• Same Tree
• Invert/Flip Binary Tree
• Binary Tree Maximum Path Sum
• Binary Tree Level Order Traversal
• Serialize and Deserialize Binary Tree
• Subtree of Another Tree
• Construct Binary Tree from Preorder and Inorder Traversal
• Validate Binary Search Tree
• Kth Smallest Element in a BST
• Lowest Common Ancestor of BST
• Implement Trie (Prefix Tree)
• Add and Search Word
• Word Search II

---

Heap

• Merge K Sorted Lists
• Top K Frequent Elements
• Find Median from Data Stream