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This trigger is used to track the application when it connected and disconnected and record logintime when user login and what program he/she runs and what action performed. Code: CREATE TABLE con_audit ( logintime TIMESTAMP DEFAULT SYSTIMESTAMP, username VARCHAR2(30), program VARCHAR2(64), machine VARCHAR2(64), session_id NUMBER, action VARCHAR2(10) );-- Trigger to track connections CREATE OR…

Error: ORA-12518: TNS:listener could not hand off client connection An error occurs when the Oracle listener fails to send a client connection request due to process limits, full connection pools, or configuration issues. Causes: The main cause of this problem is that process limit exhaustion, which occurs when the number of concurrently running processes exceeds the predefined maximum limit…

Generate CREATE Scripts Using SSMS: SQL Server Tutorial This tutorial is useful for SQL Server DBAs, database developers, SQL Server beginners, and anyone preparing for SQL Server DBA interviews. Learn how to generate DDL scripts in SQL Server using SQL Server Management Studio (SSMS). In this step-by-step tutorial, we use the AdventureWorks database to demonstrate how to generate CREATE…

Understanding PostgreSQL Index Performance Statistics Check table statistics to see index usage SELECT relname, seq_scan, seq_tup_read, idx_scan, idx_tup_fetch, CASE WHEN idx_scan > seq_scan THEN 'INDEX OPTIMIZED' WHEN idx_scan > 0 THEN 'MIXED ACCESS' ELSE 'NEEDS INDEXES' END as performance_statusFROM pg_stat_all_tablesWHERE schemaname = 'schemaname'ORDER…

To reset the PostgreSQL database password using OS authentication, follow these steps if you forget the Postgres user’s password while trying to log in. Error: C:\Program Files\PostgreSQL\18\bin>psql -U postgresPassword for user postgres:psql: error: connection to server at "localhost" (::1), port 5432 failed:FATAL: password authentication failed for user "postgres" Solution: Reset password…

Index fragmentation in PostgreSQL refers to the situation where the physical storage of the index entries is not contiguous, leading to inefficient access patterns and increased I/O operations. This fragmentation can hinder performance by requiring more time to traverse the index. To check for index fragmentation, the pg_stat_all_indexes view can be utilized, which provides statistics about each…

VACUUM in PostgreSQL is a maintenance operation used to reclaim storage by removing dead tuples from tables and indexes. It helps to optimize data retrieval by ensuring that the database runs efficiently, especially after many updates or deletes. By cleaning up the space occupied by obsolete data, VACUUM improves the performance of future queries and prevents excessive disk space usage. It’s…

What is PDB (PodDisruptionBudget)? PDB = Pod Disruption Budget ➡️ It is a Kubernetes object that controls how many pods can be down at the same time during planned (voluntary) disruptions. Don’t allow too many pods to go down together during maintenance or updates. Why we need PDB? In Kubernetes, pods can be stopped during: Node maintenance (kubectl drain) Cluster…

Connect with the postgres server and run the \dn+ command to check schema permission sudo -u postgres psql \dn+ In PostgreSQL 15+, pg_database_owner controls the public schema. The =U indicates that PUBLIC has USAGE permission. In earlier versions, =UC meant PUBLIC also had CREATE permission. For review PUBLIC permission on tables following query is used: SELECT grantee, table_schema,…

Shared Buffers:Shared buffers is a PostgreSQL memory area used as a global cache to store frequently accessed data pages from tables and indexes, helping reduce disk I/O and improve performance.All database sessions share this memory, so data once loaded can be reused by other queries quickly. Identify the more shared buffer area is requreid with help of cache hit ratio: SELECT blks_hit,…

Add grafana helm repository helm repo add grafana https://grafana.github.io/helm-charts 2. Update helm repository helm repo update 3. Install Loki helm install loki grafana/loki --namespace monitoring --values monitoring/loki-values.yaml 4. Install Grafana alloy (log collector) helm install alloy grafana/alloy --namespace monitoring --values monitoring/alloy-values.yaml 5. Verify Loki and…

Check the current version of node kubectl get nodes -o wide 2. Check the Kubernetes API Server Version kubectl version 3. Verify pods are running and distributed across nodes kubectl get pods -o wide 4. Check pod distribution kubectl get pdb 5. SSH to contact the control panel ssh <user>@<control-plane-ip>or ssh -i key.pem <user>@<control-plane-ip> 6. Verify etcd Pod kubectl get pods…

Create a Multi-Container YAML Manifest for a Pod In this blog, we will create a build pipeline for a project using a Kubernetes cluster. We will set up a multi-container pod with two containers: one for an HTTP server and another for testing the application. Create a manifest file for multi-container. I will break the file in smaller section for understanding purpose: `1. Open vi editor to…

How to create a kubernetes service for nginx pods Before creating the service, we need to add label on POD so that service able to find it. Add and check the Label to Your Pod The Service looks for Pods labeled app=nginx for your challenge. -- Add label kubectl label pod nginx app=nginx --overwriteoutput:pod/nginx labeled-- Confirm that label is addedkubectl get pods --show-labelsoutput:NAME…

Deploy a basic NGINX web server as a Kubernetes Pod and check if it’s running correctly. Step 1: Create the YAML Manifest for the Pod -- create a new yaml file using editor nano nginx-pod.yaml -- add following in file: apiVersion: v1 kind: Pod metadata: name: nginx spec: containers: - name: nginx image: nginx:latest imagePullPolicy: Never ports: - containerPort: 80 Explain: apiVersion and…

While executing the EXPDP command for taking logical backup of Oracle database schema. I am getting the following error: Error: C:\Users\Administrator>expdp dumpfile=hr_full.dmp logfile=hr_log.dmp directory=dbbackup Export: Release 19.0.0.0.0 - Production on Tue Jun 16 06:20:58 2026 Version 19.3.0.0.0 Copyright (c) 1982, 2019, Oracle and/or its affiliates. All rights reserved. Username:…

PostgreSQL uses Write-Ahead Logging (WAL) to ensure data consistency and recoverability. WAL files record every change made to the database before the actual data files are updated. By enabling WAL archiving, administrators can retain WAL files outside the database server and use them for Point-in-Time Recovery (PITR) and disaster recovery. What is WAL in PostgreSQL? WAL (Write-Ahead Log) is…