dmann's blog

Connection encryption is killing my performance! Help!

I find Encryption is blamed for a lot of performance issues so wanted to find out for myself how much of a performance hit we might be taking for common operations. There ain't no free lunch. Adding any extra processing or manipulation to an operation is going to add time to that operation.

Where can encryption be enabled when working with an Oracle database?

For Oracle there are two places to introduce encryption:

Algorithm preference in SQLNET.ENCRYPTION_TYPES_SERVER

If you have clients connecting to a server and the clients don't specify a specific encryption algorithm in SQLNET.ENCRYPTION_TYPES_CLIENT, be aware that the order of the algorithms listed in SQLNET.ORA on the server side matters... If you don't specify SQLNET.ENCRYPTION_TYPES_CLIENT from a 12.2 client configuration, a SQLNet client side trace shows the following possibilities, the choices are listed from most secure to least secure:
(3775811968) [04-OCT-2018 19:47:44:284] nam_gic: Counting # of items in "SQLNET.ENCRYPTION_TYPES_CLIENT" parameter
(3775811968) [04-O

emcli, python, jython, and module not found (ImportError No Module Named n)

I've been diving into more OEM Automation and collecting information here.

While the Oracle example scripts are a great way to find out how to interact with OEM via the emcli and python/jython interface, there doesn't seem to be much info about how this all gets done. You feed a Python script to emcli and magic happens right?

Adeesh Fulay has a great intro article here.

ASH to the rescue... for now...

After 4 unexplained crashes and a stalled Sev 1 SR I was pulling my hair out. Particularly vexing was the fact that a user was running a distributed query which was crashing a remote database. I isolated the 4 crash times for the remote database and I wanted to see what users and SQLs were running on the local database up until the crash time. So for a crash happening around 11:16 I would use the following query.
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Making ASMCMD do what you want it to do... like copy files recursively...

To troubleshoot a problem I needed to copy a database's worth of files out of an ASM diskgroup and onto the filesystem. I searched around and checked help for ASMCMD assuming there was a recursive option. I found references to one in some places on the interwebs, even official Oracle references to it like Unable To Copy Directory Using ASMCMD Cp -r Command (Doc ID 829040.1) but struck out when trying to do this on 11g and 12c ASM installs.

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ORA-01440 trying to convert FLOATs to NUMBERs

I recently came across a legacy database that was using Oracle FLOAT datatype for Primary and Foreign Keys. As the database needed some attention I was asked to get data types in order and get rid of the FLOATs in favor of NUMBER data types.

Heat map for Redo Size in SQL Developer...

I've gotten a lot of mileage out of my old SQL Developer Archive Log Count Heat Map report that I created in SQL Developer. I was recently asked to estimate the amount of redo that might be sent to a DataGuard standby. Searching The Google for this and I found some methods for calculating Network Bandwidth but I wanted to start with raw redo generated from an instance using information from v$archived_log.

Cloud Control Error EM-04050 when trying to upgrade a plugin...

I was recently asked to update the EBS Plugin from 12.1.0.2.0 to 12.1.0.3.0 in my Cloud Control 12 setup. During the prereq steps I got an error: "EM-04050: The selected plug-ins cannot be deployed on the Management Server because there are some Management Agents on which incompatible versions of these plug-ins have been deployed."

5 in 5 Vizualization 2 - Generating a d3.js visualization from a SQL Developer HTML report...

This second vizualization is more of a workflow proof of concept compared to some novel visualization but I can guarantee you haven't seen the SCOTT.EMP table like this before. I have wanted to combine my two favorite tools for a while. Here is how you can drive a d3.js visualization directly from a SQL Developer custom report.

SQL Developer 4 User Defined Reports

I enjoyed giving my presentation on SQL Developer User Defined Reports to the 2014 East Coast Oracle Users Conference. This is a local conference that is a great value and pulls in lots of fun folks that attend and present. DMann-SQLDeveloper4Reporting.pdf

Check out my GitHub project for examples and source code : https://github.com/dmann99/SQLDevUDRepPack

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