11gR2 new features

11gR2 new features:

• Intelligent data placement is a feature for Automatic Storage Management. It enables placing the most used data in disks' outer rings which have greater speed and higher bandwidth. Additionally, files with similar access patterns are located close together. Both these mechanisms increase the speed of data reads and writes.

• Advanced data partitioning capabilities for easier management of large data sets and a mechanism for compressing data as much as possible (even 4x) helping to reduce storage costs.

• Completely new database option called Oracle RAC One Node which is a one-node version of Real Application Cluster. As we can read in the documentation it makes “database highly available in the presence of computer hardware failures, software failures, or planned software maintenance events.". Importantly, pricing for Oracle RAC One Node has yet to be finalized.

• SCAN:single client access name

  
  

  One really nice new feature of 11gR2 is the SCAN (single client access name). A scan is the single point of access for all applications connecting to an 11gR2 RAC cluster and allows consistent connections without the need to know how many nodes are in a cluster. Vips are still used internally, and can still be used for connections, but the initial connection to the cluster is made via a scan. Connections to any database in a cluster will be made via the scan. No longer will a DBA need to create those large, complicated tnsnames.ora or jdbc (thin) connection strings. All can be accessed by a scan:

  sqlplus joeuser/joespasswd@dodge-scan:1521/proddb
  
  
  or
  
  
  jdbc:oracle:thin:@dodge-scan:1521/proddb

  One scan is needed for each cluster, it is a single DNS entry with three IP addresses attached to the name and set to round-robin (unless using GNS, but that is another post). The IP addresses must be unused (similar to a VIP). A good naming technique would be to name the scan after the cluster it is created for. For example, one of the clusters I use regularly contains three nodes, caravan, stratus and durango, affectionately called the Dodge cluster thus the name of the scan to be used. Once the networking folks have created the DNS entry it is ready to use. The scan is created in the cluster at installation. Note that VIPs are still needed and must still reside in DNS.

Anatomy of a SCAN

How does it all work?

A new set of cluster processes called scan listeners will run on three nodes in a cluster. If you have more than three nodes, that is ok, regardless of the number of nodes you have, there will be at most three scan listeners. If any of these clustered processes fail, they are automatically restarted on a new node. When a new connection request is made, the request hits DNS on the scan name, DNS will round robin and choose one of the three IP addresses assigned to that scan name and route it to the correct scan listener. Each scan listener keeps updated cluster load statistics and will then route the request to the appropriate VIP IP which is returned to the requesting service. The requesting service will then connect directly to the returned VIP as in previous versions and the connection is made through a standard listener. Can connections still be made directly to through the VIPs? Yes, connections via the virtual IP addresses are still supported, though I cannot see a reason to use the old method as yet. Will RAC services work with the scan? Yes, there is no difference in that functionality. SCANs are a layer on top of the old method of connecting to a RAC database and do not interfere with any current methods.

The SCAN provides a simple and effective mean to connect to any and all instances in a cluster without the need to hard code connection information which can change. This has been needed for years and is one of the best new features of 11gR2 to prevent headaches for DBAs in the future.

• In-Memory Parallel Execution

  Traditionally, parallel execution has enabled organizations to manage and access large amounts of data by taking full advantage of the I/O capacity of the system. In-memory parallel execution harnesses the aggregated memory in a system to enhance query performance by minimizing or even completely eliminating the physical I/O needed for a parallel operation. Oracle automatically decides if an object being accessed using parallel execution benefits from being cached in the SGA (buffer cache). The decision to cache an object is based on a well defined set of heuristics including size of the object and the frequency that it is accessed. In an Oracle RAC environment, Oracle maps fragments of the object into each of the buffer caches on the active instances. By creating this mapping, Oracle knows which buffer cache to access to find a specific part or partition of an object to answer a given SQL query.

  In-memory parallel query harnesses the aggregated memory in a system for parallel operations, enabling it to scale out with the available memory for data caching as the number of nodes in a cluster increases. This new functionality optimizes large parallel operations by minimizing or even completely eliminating the physical I/O needed because the parallel operation can now be satisfied in memory.

• Significant Performance Improvement of On-Commit Fast Refresh

  Fast refresh of a materialized view is now significantly faster due to reducing the time spent on log handling.

  This provides significantly reduced maintenance time and more fast refreshes are possible.

• Oracle ACFS :
  
  An exciting new feature of Oracle ASM is the Oracle Automatic Storage Management Cluster File System (ACFS) is a multi-platform file system that supports storage of software, application files, executables, trace and log files, BFILEs, configuration files, audio, video, text and any other type of application data file.  Key highlights:
  • Oracle ASM will still be used for all database files (recommended).
  • Oracle ACFS will manage non-database files.  ACFS will not support files that can be stored in ASM.

       ACFS provides:

• Dynamic file system resizing.
• Disk management through ASM disk groups.
• Mirroring capability and protection.
• Balanced I/O distribution.
• ACFS can be accessed through operating file system tools and APIs.
• Access capability through NAS, NFS and CIFS.
• Support for hundreds of thousands of files.

The ability to have a HA  file system supporting striping and mirroring across multiple platforms is pretty impressive.   With what I've seen so far, this is going to be a hot new feature in Oracle 11gR2.

• File Watcher - The job scheduler has been enhanced to be able to monitor a directory and kick off a job when a file shows up. No more writing the same shell script over and over.

• Database File System (DBFS)

  The Oracle Database File System (DBFS) enables the database to be used as a POSIX-compatible file system on Linux. This feature includes a PL/SQL package on the database server that enables the DBFS server functionality and a Linux client for DBFS (dbfs_client). The dbfs_client client is a utility that enables mounting of a DBFS file system as a mount point on Linux. It provides the mapping from file system operations to database operations. The dbfs_client client runs completely in user space and interacts with the kernel through the FUSE library infrastructure.

  DBFS Hierarchical Store provides an easy and application-transparent way to archive SecureFiles data that is stored in DBFS file systems to secondary storage tiers such as tape and storage clouds, using DBFS Links. It also allows archived data to be dearchived and brought back into the database on demand.

  DBFS makes it easy for files to be accessed by database applications, and for file-based tools to access files stored in the database. With DBFS, all important file data can be seamlessly stored in an Oracle database, providing the benefits of security, backup, performance, and scalability that are standard with the Oracle Database.

  SecureFiles is a high performance solution for storing files or unstructured data in Oracle Database. Customers often need to store these files for long periods of time for business or compliance reasons. Consequently, customers are looking to transfer files to cheaper forms of storage in an application-transparent manner to reduce manageability and administration overhead. DBFS Hierarchical Store provides a seamless, automatic, and transparent way to archive cold file data to inexpensive storage.