Oracle Database 19c is Live!

I hope that by now most of you already heard the exciting news that Oracle 19c is GA on Linux x86-64 (since 25-Apr-2019) and on Oracle Solaris SPARC 64-bit (since 26-Apr-2019). Other platforms such as Windows, HP UX, IBM AIX, etc. are targeted to be release in Q2CY19 according to Document ID 742060.1 on MOS (My Oracle Support) titled "Release Schedule of Current Database Releases"

Where should I test some of the cool new features and enhancements?
You can access LiveSQL which is a cloud-based, free platform to rung and share SQL and PL/SQL. For more info, see: https://blogs.oracle.com/oracle-database/oracle-database-19c-now-available-on-livesql

How to mitigate the performance/protection trade-off in Oracle Data Guard - Part 2 (Axxana)

Introduction

In the previous blog post titled "How to mitigate the performance/protection trade-off in Oracle Data Guard"  I reviewed the common performance vs. protection trade-off between the various data protection modes in Data Guard : Maximum performance (default), maximum availability and maximum protection.

In that blog post I mentioned how far syn can be used in order to achieve both performance (due to the smaller network latency between primary and local far sync instance) while allowing for higher data protection as the far sync instance is always synced with the primary database.

The Challenge
As the far sync instance is located in a near location to the primary database (probably the same data center), what happens if the entire data center is down due to an unexpected site disaster?
In that case there is a good chance that some of the transactions are not protected as there is an asynchronous replication between the far sync instance and the standby instance. In other words, even when using Far sync, it's not possible to guarantee RPO-0 (zero data loss).

Optional Solution
One solution that I came across in several Oracle conferences (such as Oracle OpenWorld and IOUG Collaborate) which you may consider is Axxana
Axxana is like an Oracle Database "black box" which provides a protected storage unit with DR capabilities Installed at the production site, the Black Box is designed to withstand a wide variety of extreme conditions that may occur during a disaster.

According to the official Azxxana website: "Axxana’s Phoenix for Oracle Far Sync, supported by Oracle, is a self-contained, physically indestructible solution that houses, protects, and supports the Oracle Far Sync instance from within the primary (production) data center. Because a nearby data center is not needed, the risk of a nearby synchronous site failing (e.g., due to a power outage or downed communication lines) no longer exists. Zero data loss is guaranteed, increasing the probability of successful failover. In addition, because the instance can reside at the primary site, communication lines are a matter of feet instead of miles and network latency is negligible. Given that it easily and cost-effectively resolves the challenges associated with standalone versions of Far Sync, there is simply no good reason to use the Far Sync software on any other platform—or for that matter, to use three data centers. IT leaders owe it to their company and their customers to take advantage of the risk reduction, cost savings, and other opportunities that Phoenix for Oracle Far Sync offers."

How to mitigate the performance/protection trade-off in Oracle Data Guard

Introduction
The most know trade-off in Oracle Data Guard is the performance vs. protection.
Oracle Data Guard brings several protection modes, which brings companies the flexibility in choosing the right configuration in order to meet the application SLA policies.

Data Protection Modes
There are 3 protection modes in Oracle Data Guard, which can be summarized in the following table:

Data Protection Modes - Key Considerations

•  Maximum Performance = compromise on protection 
•  Maximum Protection = compromise on performance (usually)
•  Better to use at least 2 standby databases when running maximum protection
•  NET_TIMEOUT parameter of LOG_ARCHIVE_DEST_n=30 seconds (default)

Mitigating the performance/protection trade-off in Oracle Data Guard
Oracle 12cR1 introduced a feature which can enable both performance and protection for far standby environments. For example, when the standby database is very far from the primary database, setting a "maximum protection" configuration will likely affect the performance due to the network lag and it may take time to acknowledge commit back to the primary database.
In order to address this challenge, Oracle introduced a feature  called "Far Sync". Far Sync enables having a lightweight instance which resides close to the primary database and is synchronized with the primary database. This light-wight instance has only control files, standby redo logs and archived redo logs. It does not have data files and therefore it cannot be opened for access. The redo entries will be transported from the near "far sync" instance to the "regular" standby database asynchronously.
This feature enables achieving both performance (due to the smaller network latency between primary and far sync instance) while allowing for higher data protection as the far sync instance is always synced with the primary database.

Here is an illustration of this new feature:

Licensing

This feature requires having the Active Data Guard license which is an extra option in Oracle Enterprise Edition. For more information about licensing: https://docs.oracle.com/en/database/oracle/oracle-database/18/dblic/Licensing-Information.html#GUID-B6113390-9586-46D7-9008-DCC9EDA45AB4

Useful Links

• Oracle Documentation: https://docs.oracle.com/database/121/SBYDB/create_fs.htm#SBYDB5416
• White Paper: https://www.oracle.com/technetwork/database/availability/farsync-2267608.pdf

RMOUG 2019 - Slide Decks Are Available!

Hi everybody,

I'd like to share with you the slide decks I presented on April 21 in the Rocky Mountain Oracle User Group (RMOUG) conference.
Thanks to everybody who attended my sessions.

Winning Performance Challenges in Oracle Standard Editions

Oracle Diagnostics and Tuning packs offer comprehensive, valuable performance diagnostics and tuning features such as AWR, ADDM, ASH, ASH Analytics, etc. These optional packs can be licensed only on top of the Oracle Enterprise Edition. Without these packs, diagnosing performance issues may become an overly complex task even for advanced DBAs. In this session, we’ll explore how you could use Oracle’s Statspack report and dictionary views to diagnose performance issues even without using any expensive editions and packs. Also, we’ll see how Quest tools can help DBAs diagnose and solve even the most complex performance issues without relying on the Diagnostics and Tuning packs and for all the Oracle Database editions.

https://www.slideshare.net/PiniDibask/winning-performance-challenges-in-oracle-standard-editions-132800192

Oracle Data Guard for Beginners

Oracle Data Guard is one of the most important options in the Oracle Database, as it allows organizations to ensure high availability, data protection and disaster recovery for their Oracle database environments. In this session, we’ll review the Oracle Data Guard solution from A to Z.

https://www.slideshare.net/PiniDibask/oracle-data-guard-for-beginners-134714942

Oracle Multitenant Enhancements in 18c - The Good and The Bad

Introduction
Oracle Multitenant Option is the one of the most exciting enhancements in the Oracle Database probably in the last decade. It's definitely my favorite feature since 12c due to the elegant way it simplifies database consolidation projects. For more information about Oracle Multitenant, check out my blog post: http://oracledbpro.blogspot.com/2016/10/otn-appreciation-day-oracle-multitenant.html


Oracle Multitenant 18c New Features - The Good
There are several nice Oracle Multitenant related enhancements in 18c which I believe worth mentioning in this blog post

• Refreshable PDB Switchover - In Oracle 12c Release 2, Oracle introduced the refreshable PDB feature which allows to refresh a cloned PDB either on-demand or on a scheduled frequency. You can think of it as a poor-man standby because it's not designed for failover but more for having a cloned environment updated without having to completely clone the entire database every time (which may take a while). This could be very helpful for reporting/query offloading. Oracle 18c took this feature one step ahead and now enables to perform a switchover between the 2 PDBs which could be useful for load balancing purposes (planned switchover) as well as high availability when a PDB fails. Please note that this feature is not a replacement for data guard and should not be used as a DR solution for mission critical applications
• Enhanced Data Guard Integration - In Oracle 12c, when Multitenant was configured in a data guard environment there were some challenges. Oracle 12cR2 introduced the hot clone feature which was a huge improvement as it allowed cloning a PDB with no downtime; however, when hot cloning a PDB, it was not performed on standby - in other words, it wasn't replicated also in the standby CDB (similar to specifying standbys=none). In Oracle 18c this challenge has been addressed by additional steps which required to be done. For more details, see: https://www.oracle.com/technetwork/database/multitenant/learn-more/multitenantwp18c-4396158.pdf
• Snapshot Carousel - Stores historical point in time copies of pluggable databases (up to 8 in the current 18c release). This is useful for historical debugging of data related issues as well as for point-in-time recovery of a PDB (similar to flashback database feature, but without enabling flashback database)
• CDB Fleet Management - CDB allows to manage many PDBs as one (up to 4096 PDBs in Oracle Exadata and Oracle cloud, and 252 for every other deployment) - which is the main benefit of database consolidation. Now, in Oracle 18c using this new feature it's possible to manage many CDBs as one. I personally think this could be useful for the very large enterprise companies who manage huge amount of databases)

Oracle Multitenant 18c New Features - The Bad
According to Oracle documentation, all the above features (except the enhanced data guard integration), are only available either on Oracle Exadata or Oracle cloud. Most of the Oracle customers probably don't use neither Oracle Exadata nor Oracle cloud which makes these features unavailable for most Oracle customers. I hope this will be changed in the future.

Useful Links

• Oracle 18c Multitenant White Paper
• Oracle 18c Licensing Information