An Oracle blog about Exadata

Exadata System Software 19.1 – The Foundation for the Autonomous Database

Exadata System Software Release is now generally available. This release lays the foundation for the Autonomous Database and improves every aspect of Exadata with 20+ features and enhancements. All new features and enhancements are available on all supported Exadata generations, protecting customer investment across all Exadata deployment models: on-premises, Cloud Service, and Cloud @ Customer.

In this post we outline key enhancements for automated performance management, improved operations via Oracle Linux 7, and improved availability and security. We also discuss new improvements for even faster Smart Scan performance. Later posts will discuss individual features, and the impatient can also review the full documentation or tune in to this webcast.

Automated, Cloud-scale Performance Monitoring

The ability to automatically detect and report anomalies to enable software or persons to take corrective actions is crucial to cloud-scale autonomous infrastructure. Release automates monitoring of CPU, memory, Input/Output, file system, and network – customers need only configure the notification mechanism. This automation combines machine learning techniques with the deep lessons learned from thousands of mission critical real-world deployments.

For example, Exadata can detect that hogging of system resources is affecting database performance, identify the culprit runaway process, and issue an alert, without any pre-existing set-up. To benefit from automatic performance monitoring, all you need to do is configure the notifications.

Oracle Linux 7

With Release, both database and storage servers now run on Oracle Linux 7 Update 5, which brings further performance and reliability improvements. Upgrading to Oracle Linux 7 does not require re-imaging the database servers, and can be done in a rolling fashion, without requiring any downtime. Our customers can now easily upgrade to the most modern Operating System for running the Oracle Database with no outage, no re-imaging, period.

Oracle Linux 7 enables Exadata servers to boot faster, and it improves ksplice and kexec, key enablers to nonstop Exadata operation. Also, with Oracle Linux 7, Exadata moves to chrony to further reduce jitter via better and faster time synchronization with NTP servers.

Even Higher Availability

For OLTP workloads, Release makes the addition of new Flash devices to Exadata more transparent, for even higher availability. When a Flash card is replaced, I/O from that card can be delayed as data must be read from disk. 

This delay is now mitigated by prefetching, in the background, the most frequently accessed OLTP data into the Flash cache. The key is using algorithms similar to the ones introduced for In-Memory OLTP Acceleration, which ensure that the blocks that were most important to the database are fetched first.

This feature provides better application performance after the failure of a Flash device or a storage server by partially duplicating hot data in the Flash cache of multiple storage servers. It works for write-back Flash cache (as there is no secondary mirroring for write-through Flash cache), and it is useful for OLTP workloads, as it does not cache scan data.

Even Better Security

Release security improvements include support for Advanced Intrusion Detection Environment (AIDE), enhanced Secure Eraser, and the addition of access control lists to the Exadata RESTful service. See documentation for the full list of security improvements.

AIDE tracks and ensures the integrity of files on the system to detect system intrusions.

Secure Eraser now supports erasing data disks only (i.e., excluding system disks), and erasing individual devices. On supported hardware, Secure-Erase is automatically started during the re-imaging of hardware, which simplifies re-imaging without performance penalty. Also, when users specify the disk erasure method 1pass, 3pass, or 7pass, Exadata System Software uses Secure Erase if the hardware supports it, for a dramatically shorter erasure time, especially on today’s very large disks.

Customers can now specify a list of IP addresses or IP subnet masks to control access to the Exadata RESTful service, or they can disable access altogether.

Another security-related change is that Smart Scan and ExaWatcher processes now run under new, less privileged, operating system users. For details, see documentation.

Even Faster Smart Scans

We call out further improvements to Smart Scan, a flagship innovation in the first Exadata Database Machine, as a good example of Oracle’s commitment to continuing technical innovation. Release increases Smart Scan performance by enabling checksum computation at the column level. Checksum validation is key to Exadata’s comprehensive error detection, and it may happen during data storage or retrieval. For in-memory columnar format data on Exadata Smart Flash Cache, the checksum is now computed and validated at the column level rather than full block, enabling two important optimizations, as follows.

Selective checksum computation: When Smart Scan reads a Flash block checksum, it now performs checksum verification only on the specific (scan) column Compression Units (CUs), ignoring other columns in the cache line, reducing CPU usage. For example:

SQL> SELECT temperature FROM weather WHERE city = 'NASHUA' AND weather = 'SNOW' 
AND weather_date BETWEEN '01-JUN-18' AND '30-DEC-18';

Checksums are computed only on columns temperature, city, weather, and weather_date, even though the table may have many other columns.

Just-in-time checksum computation: checksums are performed only when and if a column is processed. For example:

SQL> SELECT temperature FROM weather WHERE city = 'REDWOOD CITY' AND weather = 'SNOW' 
AND weather_date BETWEEN '01-JUN-18' AND '30-DEC-18';

Since city = ‘REDWOOD CITY’ and weather = ‘SNOW’ returns no results, no checksum is done for columns weather_date and temperature. Less data on which to perform checksum reduces CPU usage.

This feature is automatically enabled when you configure the INMEMORY_SIZE database initialization parameter and upgrade to Oracle Exadata System Software release

For more details see documentation.


This post covered the main innovations and enhancements in the new Exadata software release. You get everything outlined here, and more, just by upgrading your Exadata software, with no additional costs. Heck, you don't even need to do that yourself: Oracle Platinum Services or our Cloud Operations team will take care of it at no charge.

We are always interested in your feedback. You are welcome to engage with us via Twitter @ExadataPM and by comments here.

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Comments ( 1 )
  • Andres Szmulewicz Thursday, October 25, 2018
    Between 12.2, 18, and 19, Exadata has really improved massively in the past year. Thank you for the blog Gurmeet!
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