No more stale statistics in 19c

There is an odd contradiction that we all encounter for most databases, especially if they are predominantly used during the business day. Here is how that contradiction comes to be – it is in the way that we obtain and use optimizer  statistics on those databases. The contradiction runs like this:

  • To minimize service disruption, we gather statistics at a quiet time, for example, in the middle of the night
  • We then use those statistics (more...)

2019 Public Appearances (What In The World)

I’ll be presenting at a number of Oracle events over the remainder of the year. Details as follows: Oracle Open World – San Francisco (16-19 September 2019) Advertisements

Find Docker Container IP Address?

This is just simple post for later reference, if I need it …

In setting up some docker containers for testing Oracle GoldenGate, I needed to find the IP address of the container where my database was running (I keep my database in a seperate container in order not to rebuild it every time).

To find the address of my database container, I had to use the docker “inspect” command. This command returns (more...)

Identifying the TNS_ADMIN for an deployment in GoldenGate Microservices

Setting up network routing/access with Oracle GoldenGate Microservices (12.3 and later) can be an interesting experience. As many in the Oracle space knows, you simply have to setup TNS_ADMIN to point to the location where your sqlnet.ora and tnsnames.ora files are located. This would normally look like this:


export TNS_ADMIN=${ORACLE_HOME}/network/admin


or


export TNS_ADMIN=$(ORA_CLIENT_HOME}/network/admin

 

These examples still working for Oracle GoldenGate Classic, however, when we start looking at this through the lens (more...)

gather_system_stats

What happens when you execute dbms_stats.gather_system_stats() with the ‘Exadata’ option ?

Here’s what my system stats look like (12.2.0.1 test results) after doing so. (The code to generate the two different versions is at the end of the note).


System Stats
============
Status: COMPLETED
Timed: 13-Aug-2019 15:00:00 - 13-Aug-2019 15:00:00
--------------------------------------------------
CPUSPEED        :
CPUSPEEDNW      :          918
IOSEEKTIM       :           10
IOTFRSPEED      :      204,800
MAXTHR          :
MBRC            :          128
MREADTIM        :
SLAVETHR        :
SREADTIM         (more...)

Löschung von automatisch erzeugten Indizes in Oracle 19c

Die automatische Generierung von Indizes durch das "Auto Indexing" in Oracle 19c sieht auf den ersten Blick wie ein ausgesprochen interessantes Feature aus. Das ist sie zweifellos auch. Wie gut sie funktioniert, ist ein anderes Thema. Franck Pachot zeigt, dass es zumindest nicht ganz leicht ist, die automatisch generierten Indizes wieder los zu werden: mit einem simplen "drop index" klappt das schon mal nicht - und ob manuelle Anpassungen in sys.ind$ tatsächlich eine gute (more...)

Pandas – ValueError: If using all scalar values, you must pass an index

Reading json file using Pandas read_json can fail with “ValueError: If using all scalar values, you must pass an index”. Let see with an example –

cat a.json
{
  "creator": "CaptainAmerica",
  "last_modifier": "NickFury",
  "title": "Captain America: The First Avenger",
  "view_count": 12000
}
>>> import pandas as pd
>>> import glob
>>> for f in glob.glob('*.json'):
...     print(f)
...
b.json
c.json
a.json
>>> pd.read_json('a.json')
Traceback (most recent call last):
  File  (more...)

Analyzing the 2019 Tour de France in depth using Strava performance data from Race Riders

This year’s Tour de France was quite a spectacle. Great performances, exciting stages, unexpected events: it had it all. Analyzing the race events as they unfolded during the stages of this year’s Tour is something I am keen to attempt. Using Jupyter Notebooks, Python and Pandas and Plotly for visualization, I am sure I can get more detailed stories extracted from raw race data. The starting point for such analysis activities is… the data.

However, (more...)

Menu Popup with Declarative List

In the past when I’ve needed to add half a dozen or more buttons to a page, I’ve sometimes encased them in a Collapsible region so that the user can slide them out of the way instead of clogging up the screen. Recently however I’ve started (sparingly) using a Menu Popup, as per this tutorial. The issue I have with this method, however, is that the menu items are defined in a shared component (more...)

Oracle Error Bash f(x)

My students always struggle initially with basic Linux skills. I wrote little function for their .bashrc file to help them avoid the frustration. It finds and displays all errors by file name, line number and error message for a collection of log files in a single directory (or folder).

errors()
{
  # Determine if any log files exist and check for errors.
  label="File Name:Line Number:Error Code"
  list=`ls ./*.$1 | wc -l`
  if [[ $list}  (more...)

Azure VMs with Oracle- Next Steps

Microsoft has done a great job of documenting how to create a VM with the appropriate VM image and Oracle version, then how to log in, startup the listener and create the database.  I just have some enhancements I’d like to make to it, hoping to help it move up one level.

I Bequeath to You

All instructions provided by the Microsoft documentation show how to connect to the database using a bequeath, (BEQ) (more...)

Create Oracle User

After you create and provision the Oracle Database 11g XE, you create an instance with the following two step process.

  1. Create a student Oracle user account with the following command:

    CREATE USER student IDENTIFIED BY student
    DEFAULT TABLESPACE users QUOTA 200M ON users
    TEMPORARY TABLESPACE temp;
    

  2. Grant necessary privileges to the newly created student user:

    GRANT CREATE cluster, CREATE indextype, CREATE operator
    ,     CREATE PROCEDURE, CREATE SEQUENCE, CREATE SESSION
    ,     CREATE TABLE, CREATE TRIGGER, CREATE  (more...)

Multi-table

Here’s a problem (and I think it should be called a bug) that I first came across about 6 years ago, then forgot for a few years until it reappeared some time last year and then again a few days ago. The problem has been around for years (getting on for decades), and the first mention of it that I’ve found is MoS Bug 2891576, created in 2003, referring back to Oracle 9.2.0. (more...)

Obvious But Not For Oracle Obviously

While dropping RAC database, I found error ORA-01081: cannot start already-running ORACLE – shut it down first from dbca log.

Looking up error: Cause is obvious

$ oerr ora 01081
01081, 00000, "cannot start already-running ORACLE - shut it down first"
// *Cause:  Obvious
// *Action:

Here is the process for 12.1.0:

$ ps -ef|grep pmon
oracle   41777     1  0 Aug09 ?        00:00:30 asm_pmon_+ASM2

$ srvctl config database
DBFS

$ srvctl status database -d  (more...)

Last Week in Stream Data Integration & Stream Analytics – 12.8.2019

This is the 166th edition of my blog series blog series around Stream Data Integration and Stream Analytics!

This time it is actually for two weeks, as I was too busy to release one earlier. From next week I hope to get back to a weekly cycle. As every week I was also updating the following two lists with the presentations/videos of the current week:

As usual, find below (more...)

ADW – Loading data using Object Storage

There are a number of different ways to load data into your Autonomous Data Warehouse (ADW) environment. I’ll have posts about these alternatives.

In this blog post I’ll go through the steps needed to load data using Object Storage. This might appear to have a large-ish number of steps, but once you have gone through it and have some of the parts already setup and configuration from your first time, then the second and subsequent (more...)

Vagrant : Oracle Database Build (19c on OL8)

Today’s video is an example of using Vagrant to perform an Oracle database build.

In this example I was using Oracle 19c on Oracle Linux 8. It also installs APEX 19.1, ORDS 19.2, SQLcl 19.2, with ORDS running on Tomcat 9 and OpenJDK 12.

If you’re new to Vagrant, there is an introduction video here. There’s also an article if you prefer to read that.

If you (more...)

How to install Oracle Linux on a Raspberry Pi – the easy way

In one of my past posts I showed how one can install Oracle Linux on a Raspberry Pi from a Mac via the command line. Luckily my colleague Philippe pointed out to me that things can be even much, much easier thanks to Etcher, an open source tool to flash SD cards and USB drives. … Continue reading "How to install Oracle Linux on a Raspberry Pi – the easy way"

Interval expressions

I just learned a lot about these critters thanks to an ODC forum question: how to calculate the difference between two dates in calendar years and months, days, hours, minutes and seconds.

Fedora 30 Missing Library

Having run into an obsolete library issue installing Oracle Database 18c XE on Fedora, Version 30, I opted to revert my student image to Oracle Database 11g XE. The installation went without issue but when I tried to log into SQL*Plus as the oracle user, I got the following error message:

sqlplus: error while loading shared libraries: libnsl.so.1: cannot open shared object file: No such file or directory

The libnsl.so.1 library (more...)