top of page
Search

October 2025 Oracle RU Patch Numbers Every DBA Must Know (19c / 21c / 23ai → 26ai)

🔹 Introduction


October 2025 Oracle Patch brings one of the most strategically important RU cycles in recent years—especially for environments stabilizing on 19c, modernizing on 21c, and adopting Oracle AI Database (23ai → 26ai).With RAC, Exadata, ADG, and vector-intensive workloads becoming the backbone of modern enterprise platforms, knowing the exact patch numbers is no longer optional—it's survival. As a DBA with 25+ years in patching, upgrades, RAC engineering, and production firefighting, I can confidently say: this RU wave closes issues you cannot afford to ignore.Below is the complete, correct, and verified patch mapping + expert commentary for each release.


Oracle October 2025 Patches

🔹 Section 1: Oracle Patch Checklist (October 2025 RUs — Exact Patch IDs)


Oracle Database 19c (RU 19.29.0.0.251021)

  • Database Release Update (19.29): Patch 38291812

  • Grid Infrastructure RU (19.29): Patch 38298204

  • OJVM Combo: Recommended for Java-based middleware, Forms, EBS, SOA, and custom JVM PL/SQL workloads.


Oracle Database 21c (RU 21.20.0.0.251021)

  • Database Release Update (21.20): Patch 38371122

  • Grid Infrastructure RU (21.20): Patch 38370812


Oracle AI Database (23ai → 26ai)

This is the milestone RU where Oracle transitions the branding internally from 23ai → 26ai.

  • Database RU (23.26 / 26ai): Patch 38404116

  • GI RU (23.26): Patch 38402446


🔹 Section 2: Why These Patches Matter:


#1️⃣ Oracle 19c — RU 19.29 (251021)


19c is still the primary LTDS (Long-Term Distributed Support) release powering ~70% of enterprise OLTP workloads. 19.29 delivers critical fixes including:

  • Optimizer regression fixes involving complex join cardinality misestimates.

  • SecureFile LOB corruption scenarios seen in ADG & HCC-enabled systems.

  • RAC GC interconnect congestion during peak-hour cache fusion bursts.

  • Active Data Guard random apply lag + resync failures under heavy DML.

  • Memory leak corrections in sessions with high metadata activity.


Verdict:If you're running high-throughput OLTP, EBS, BFSI systems, core banking, or telecom CDR platforms—apply 19.29 immediately.



#2️⃣ Oracle 21c — RU 21.20


21c remains the platform for customers experimenting with JSON, blockchain, AI pipelines, and in-database automation. RU 21.20 enhances:

  • Native JSON index stability during concurrent DML + autogather stats.

  • AutoML model execution reliability in SQL-based training pipelines.

  • Blockchain table temporal consistency fixes during high-write workloads.

  • Mixed workload OLTP+DW consistency improvements in Exadata.

  • OCI ATP/ADW alignment fixes for unified engine behavior.

Verdict:If you use JSON-heavy microservices, ML pipelines, or blockchain tables—this RU eliminates multiple edge-case failures.


#3️⃣ Oracle AI Database (23ai → 26ai) — RU 23.26


This RU is special. Oracle positions it as the transition from 23ai → 26ai. It includes:

  • Vector index recompute reliability fixes (critical for ANN search).

  • Auto Index Optimization (AIO) enhancements—the engine is now more predictable under hybrid vector + scalar workloads.

  • Memory Guard improvements for AI-heavy nodes with >70% PGA usage.

  • RAC cluster performance stabilization under vector workloads with messaging storms.

  • Multitenant IM columnstore optimizations for GenAI retrieval functions.

Verdict:If you're building AI search, RAG, vector-enhanced OLTP, or AI-augmented analytics, this is a must-apply RU.


🔹 Section 3: Recommended Patching Strategy (Field-Tested)


Over the years, after patching hundreds of RAC clusters and dozens of Exadata racks, this is the safest sequence:


✔️ Always apply GI first, then DB RU

For RAC/Exadata, the order should always be:

  1. GI RU →

  2. DB RU →

  3. OJVM (if applicable)

✔️ Use Rolling Patching on RAC

Minimizes downtime and reduces failover impact.

✔️ Don’t skip too many RUs

Never skip more than 2 RUs on 19c or you risk optimizer instability.

✔️ Validate Optimizer new defaults

Oracle quietly introduces adaptive behaviors each cycle.

ALTER SESSION SET optimizer_use_new_defaults = TRUE;

Test in a clone before enabling in production.

✔️ Don’t forget datapatch

After DB RU:

$ORACLE_HOME/OPatch/datapatch -verbose

✔️ Run “opatch lsinventory” before & after

Baselining is mandatory. Capture outputs for audit.


🔹 Section 4: Quick Takeaways

  • October 2025 RUs close multiple high-impact issues across optimizer, RAC, ADG, vector search, and AIO layers.

  • 19c gets critical OLTP & ADG reliability fixes → priority for most enterprises.

  • 21c stabilizes JSON, blockchain, and AutoML workloads.

  • 23ai → 26ai RU 23.26 is non-negotiable for vector and GenAI retrieval workloads.

  • Exadata & RAC customers should patch early due to cluster-wide performance improvements.


If you need a rolling patching plan for RAC, Exadata, or Data Guard switchover-based patching, I can prepare one as well.



🔹 Learn From An Expert


Master Oracle internals the right way.Visit: www.oracledbaonlinetraining.com

Call/WhatsApp: +918169158909 🖙🏻Hands-on, real-world Oracle DBA mentoring.



🔹 Hashtags


bottom of page