How to free Oracle FRA space properly

Oracle Flash Recovery Area is full will made your database stop working for normal user and produce ORA-19815 warnings, ORA-00257: archiver error. Connect internal only, until freed.

So, you need to free up more space for Oracle FRA.

First of all, NEVER try to delete … Read the rest “How to free Oracle FRA space properly”

Understanding Oracle Idle time parameter in Profile

Quick & clear answer:

The idle_time parameter limits the maximum time a session can stay connected without doing anything. By reducing the period of time an inactive session stays connected, the performance of the whole system significant increased.

Why Idle time parameter helps increase

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How to show all configuration in Oracle database

Showing all configuration in Oracle databases can be done in several ways.

Using v$parameter system table

Logging in as SYS or any account with sufficient privileges and run this command.

SELECT * FROM v$parameter;

To search specific parameter

SELECT * FROM v$parameter WHERE NAME LIKE 
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How to limit number of sessions per user in Oracle database

Limiting sessions per user (connection per user) is an important task of DBA so we can make sure that one arbitrary application with a specific credential can not overkill whole database.

Step 1: Enable database resource limit

By default, Oracle disable resource limit. You need … Read the rest “How to limit number of sessions per user in Oracle database”

Understanding Oracle Session vs Connection vs Process

The relationship between Oracle Session vs Connection and Process may be the most embarrassing to professional or season dba. But its really an important article, as a DBA, you should understand that clearly.

A connection is a physical circuit between you and the database.

A … Read the rest “Understanding Oracle Session vs Connection vs Process”

Understanding Hibernate database connection pool and fix SQLTransientConnectionException: HikariPool-1 – Connection is not available, request timed out after 30000ms.

It’s quite a long title, isn’t it? I recently has a question from some dev about SQLTransientConnectionException: HikariPool-1 – Connection is not available, request timed out after 30000ms. error that their application sometimes has had. After taking a few time with them to check their … Read the rest “Understanding Hibernate database connection pool and fix SQLTransientConnectionException: HikariPool-1 – Connection is not available, request timed out after 30000ms.”

How to check number of sessions of a user in Oracle

To calculate number of session per username with status and detail source address, original OS user in Oracle database, you can use this command.

SELECT USERNAME, STATUS, OSUSER|| '@' || MACHINE AS SOURCEINFO, COUNT(*) AS NUMOFCONN 
 FROM v$session 
 WHERE TYPE = 'USER'
 GROUP BY USERNAME, 
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How to allow remote root access MariaDB 10.4 on Centos 7




By default, MariaDB not allow you access as root from anywhere but localhost. In order to allow remote root access to MariaDB, follow these steps.

Step 1: Accessing MariaDB on local

Use this command

sudo mysql -u root

Step 2: Grant access for root remotely

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Use distinct in php MongoDB query




Use distinct in php MongoDB query

In my cars_positions database and positions collection I have this kind of data :
db.positions.find()
{ “_id” : ObjectId(“536a5cd9e9df25cd8609d286”), “car” : { “type” : “sport”, “ref” : “nameOfTheCar1” }, “position” : { “dateTime” : “2014-05-06T06:42:10”, “latitude” : “0000.1111”, “hemesphere” … Read the rest “Use distinct in php MongoDB query”

How to implement a cron job (using node-schedule) in a Node JS application




How to implement a cron job (using node-schedule) in a Node JS application

It has been a few days I have started learning Node JS.
My Node JS application has a get api which fetches the books information from the MongoDB database in json format … Read the rest “How to implement a cron job (using node-schedule) in a Node JS application”