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Franck Pachot

Franck Pachot

AWS: PostgreSQL on Graviton2

By | AWS, Postgres | No Comments

By Franck Pachot . On the AWS free tier, you can run a t2.micro instance for 750 hours per month during the first 12 month after sign-up date. And currently, until June 2021, you can also run a T4g.micro. But be careful, when the free trial ends, or if your usage exceeds the free trial restrictions, you’ll pay the standard pay-as-you-go rates. This is a good occasion to test the Graviton2 ARM processors, and you…

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Franck Pachot

Delphix: a glossary to get started

By | Oracle | No Comments

By Franck Pachot . dbi-services is partner of Delphix – a data virtualization platform for easy cloning of databases. I’m sharing a little glossary to get started if you are not familiar with the terms you see in doc, console or logs. Setup console The setup console is the first interface you will access when installing Delphix engine (“Dynamic Data Platform”). You import the .ova and start it. If you are on a network with…

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Franck Pachot

Oracle Rolling Invalidate Window Exceeded(3)

By | Oracle | No Comments

By Franck Pachot . This extends a previous post (Rolling Invalidate Window Exceeded) where, in summary, the ideas were: When you gather statistics, you want the new executions to take into account the new statistics, which means that the old execution plans (child cursors) should be invalidated You don’t want all child cursors to be immediately invalidated, to avoid an hard parse storm, and this is why this invalidation is rolling: a 5 hour window…

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Franck Pachot

Oracle DB on Azure with Multitenant Option

By | Cloud | 3 Comments

By Franck Pachot . If you want to run an Oracle Database in the Microsoft Azure cloud, you will install it yourself on a VM. And then, you can expect the same as when you install it in your premises, in a virtual environment. Except that Oracle makes it two times more expensive by accepting to license the processor metric on vCPUs at the condition that the Intel core factor is not applied. And in…

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Franck Pachot

Grafana, SQL and IN() list for multi-value variable

By | Database Administration & Monitoring | No Comments

By Franck Pachot . I’ve recently looked at Grafana. Pros: it is really nice, I mean aesthetically. If you want to build a dashboard for your boss, or put it on a large screen in the open space, that’s beautiful. Cons: not mature. I’m working for years with technology that works. When I have a problem, I find the solution (blog posts, forums, mailing lists, support notes)… But with modern software, the first problems I…

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Franck Pachot

PostgreSQL on Linux: what is cached?

By | Postgres | No Comments

By Franck Pachot . In a recent tweet I wanted to highlight the importance of knowing what you measure with pgbench, because looking at “Transactions per second” without knowing if you are in shared buffer cache hits, or filesystem cache hit, or storage cache hit, or physical read… is just meaningless: https://twitter.com/FranckPachot/status/1358761092307169282?s=20 The “scale” with the default pgbench tables stores about 15MB per scale value, mostly in the pgbench_accounts table and indexes. The default select-only…

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Franck Pachot

Learn ODA on Oracle Cloud

By | Oracle | No Comments

By Franck Pachot . You want to learn and practice your ODA command line and GUI without having an ODA at home? It should be possible to run the ODA image on VirtualBox but that’s probably a hard work as it is tied to the hardware. About the configuration, you can run the Oracle Appliance Manager Configurator on your laptop but I think it is not compatible with the latest odacli. However, for a long…

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Franck Pachot

Google Cloud SQL Insights: ASH, plans and statement tagging

By | Cloud, Postgres | No Comments

By Franck Pachot . Looking at database performance has always been necessary to optimize the response time or throughput, but when it comes to public cloud where you are charged by resource usage, performance tuning is critical for cost optimization. When looking at host metrics, you see only the symptoms and blindly guess at some solutions: add more vCPU if CPU usage is high, more memory if I/O wait is high. And this can be…

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Franck Pachot

19c serverless logon trigger

By | Oracle | No Comments

By Franck Pachot . I thought I already blogged about this but can’t find it. So here it is, with a funny title. I like to rename oracle features by their user point of view (they are usually named from the oracle development point of view). This is about setting session parameters for Oracle connections, directly from the connection string, especially when it cannot be set in the application (code) or in the DB server…

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Franck Pachot

Pressure Stall Information on Autonomous Linux

By | Database Administration & Monitoring | No Comments

By Franck Pachot . The Linux metrics that are usually considered for performance monitoring and troubleshooting have many drawbacks and frequent misinterpretations. The recent kernels provide PSI (Pressure Stall Information) which is not enabled by default in Oracle Linux “unbreakable” kernel. However, the kernel is compiled with it. Here is how to enabled it in a newly create Autonomous Linux instance (the Oracle Cloud Linux ,based on OEL 7.9, with no-downtime patching) Check PSI availability…

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