Prior to Oracle 19c, when using the "Flashback Database" feature on a primary database in a data guard environment would result in a standby database which is no longer in sync with the primary database; in previous releases, in order to ensure both primary and secondary are synced, then a manual procedure to flash back to standby database was required.
Starting with Oracle 19c, a standby database that is in a mounted state can automatically follow the primary database after a RESETLOGS operation on the primary. This simplifies standby management after a RESETLOGS operation on the primary.
This process is handled by the MRP (Managed Recovery Process) process that will automatically do the work for us.
One of the most valuable security related features which have been introduced recently (in Oracle 12c to be specific) is the Privilege Analysis feature. Using this feature, the DBA can easily understand which privileges are actually being used by users. Once the analysis has been completed, the DBA can revoke all of the unnecessary privileges/roles. I actually wrote a dedicated blog post about this topic with some code examples. See: http://oracledbpro.blogspot.com/2015/12/oracle-12c-privilege-analysis.html
Oracle Database 19c Positive Licensing Update! Prior to version 19c, this extremely helpful and useful feature was only available for Enterprise Edition with Oracle Database Vault (extra cost option). Starting from 19c this feature is available with Enterprise Edition; in other words, no need for the data vault option which, is mentioned previously, is an extra cost option.
This is a really nice update from Oracle - let's hope that one day the Diagnostics & Tuning pack features (e.g. AWR, ADDM, ASH, etc.) will be included with the Enterprise Edition without forcing customers to buy the extra cost diagnostics & tuning packs options :)
Introduction For so many years (starting in the early 2000's, when 10g was released) Oracle RAC option (Real Application Clusters) was available with Oracle Standard Editions; even when Oracle introduced Oracle Standard Edition 2 (SE2) back in version 22.214.171.124 (see my blog post about SE2 here), they offered the RAC option.
19c Update With the introduction of the recent 19c release, Oracle did a pretty significant change with SE2 which I believe is worthy of a blog post. Oracle RAC has been de-supported effective with Oracle Database 19c. According to Oracle, "SE2 Socket requirements are hard to meet as hardware evolves." In addition, they claim that "SE Oracle RAC has seen diminishing demand with increased high availability requirements, as SE does not provide the full set of high availability capabilities available in the Oracle Database Enterprise Edition".
My Own View
I personally feel like Oracle licensing is too strict and with this recent change it became even stricter. For example, I always believed that Diagnostics and Tuning packs should have been part of the Enterprise Edition by default. I felt like the move to Standard Edition 2 back in 126.96.36.199 was strict as it was more limited than Standard Edition with the same price. I believe that the recent 19c SE2 change is a (valid) tactic to move people to Oracle cloud. The positive news is that from my experience of working with my customer base, the impact on the market should be very low as it's pretty rare to see customers use SE2 with RAC given the limitations of SE2.
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"
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."
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.
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.
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.
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.
Last week (on October 4th) I presented a webinar for IOUG titled "Winning Performance Challenges in Oracle Standard Editions". For those who missed the webinar a recording is available here: http://www.ioug.org/p/cm/ld/fid=153
Abstract: 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 a very complex task – even for advanced DBAs. In this session we will explore how you could leverage Oracle’s Statspack report and dictionary views to diagnose performance issues even without using any expensive editions and packs. In addition we will see how Quest tools can help DBAs to diagnose and solve even the most complex performance issues without relying on the Diagnostics and Tuning packs and for all the Oracle Database editions.