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Zero Downtime, Zero Risk Oracle Migrations

As the world of data is constantly, exponentially expanding and uptime requirements are following suit, this presents problems for not only storing that data, but how to migrate it between Oracle versions.

Oracle Database 12c presents some compelling benefits, but if we cannot move our multi-terabyte database to it without significant downtime, we may not be able to realistically leverage them. Similarly, when Management ask us how this new 12c database will perform, the traditional answers of “It will probably be better for most SQL statements but will require a little tweaking for others” tends to be less palatable.

So how do we migrate large amounts of data to newer Oracle releases, meet business uptime requirements and guarantee the performance of the new environment?

One technology that can help us here is Real Application Testing. This allows us to capture actual application transactions from a 10g or 11g database, and play it back against an 11g or 12c target database. Along with the SQL Performance Analyzer tool, this will highlight the performance of individual SQL statements, showing in a graphical format those which are running the same or better than the old release, and those which need to be tuned. Even better, we can increase the number of workload replay slaves to simulate higher volumes of traffic, allowing us to answer questions like “How will this platform perform in 3 years?”

We could potentially use RMAN or Datapump to populate the new database and still leverage Real Application Testing, however this does not address our requirement for migrating to the new platform in a minimal downtime window.

Oracle GoldenGate fills the gap here by allowing us to replicate from our legacy Production database into the new version database, keeping it in sync. We can then pause GoldenGate replication, take a flashback restore point, and then capture and replay workload against the new database using Real Application Testing. This allows us to experiment with tuning methodologies and repeatedly test the new version, while still being able to flash it back and bring it back in sync with GoldenGate.

When testing is complete and performance has been tuned to an acceptable level, cutover to the new database can be accomplished by simply repointing the application servers at it. This could even potentially be performed in a rolling fashion, completely eliminating the need for downtime.

You’ll certainly find that your Management team is happier with the idea of “Zero Downtime, Zero Risk Migrations”!

Cintra is one of only a handful of Oracle partners worldwide specialized in these technologies, so get in touch with us today to learn how your business could make use of them.

Written by Simon Rice, Database Solutions Architect

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