In earlier versions of Oracle Database, statistics were collected mainly through scheduled jobs using DBMS_STATS. This often resulted in stale statistics between collection intervals, especially in OLTP environments with frequent DML operations. Oracle 19c introduces Real-Time Statistics, a feature that collects optimizer statistics immediately during DML operations such as INSERT, UPDATE, MERGE, and CREATE TABLE […]
What is Point-in-Time Recovery? Point-in-Time Recovery is a technique to restore a database to a specific moment in the past. Unlike complete recovery (which applies all redo/archived logs until the most recent commit), PITR deliberately stops recovery at a chosen point. Demo Scenario Let’s simulate a common situation: Step 1: Setup and Insert Data At […]
Linux patching (OS security updates, kernel upgrades, etc.) is a routine activity for system administrators. For Oracle RAC environments, DBAs must ensure pre-patching checks, safe shutdowns, and post-patch relinks are properly executed to avoid service disruption. 1. Why Pre-Patching Checks Are Critical Before handing over the server to the Linux team, DBAs must: These pre-checks […]
When working with ROLLUP or CUBE, you’ll notice NULL values appear in subtotals and grand totals.But how do you tell the difference between a real NULL value in the data and a NULL that just means “subtotal here”? That’s where GROUPING_ID comes in. It returns a numeric code indicating which columns are aggregated (rolled up). […]