My MySQL database impressions

I have been in the data and database world for over a decade now, working with mainly Oracle and data integration projects with Salesforce.

I have also spent time working with MySQL a relational database with open source roots, now part of Oracle. In this post I want to talk about my impressions of MySQL and some tips and tricks I learned working with it.

First and for all, you will have to be ready (more...)

The OLAP Extension is now available in SQL Developer 4.0



Oracle Database 11gR2 (11.2.0.4) installation on Oracle Linux 6.4

In this post, I’m installing the Oracle Database 11g Release 2 (11.2.0.4) software on Oracle Linux 6.4, along with optional instructions on how to apply the latest Patch Set Update (PSU) to your new Oracle home. First and foremost, before you start, make sure your Linux server meets the minimum hardware requirements: 1GB of RAM (plus

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OSD-04400: unable to acquire internal semaphore for process and OS 183 (Windows)

I hit the following problem with a 9.2.0.8 database running on Windows 2003 this morning (info pulled from the alert log).  The database had failed to restart after a client’s cold backup process ALTER DATABASE MOUNT Wed Jan 15 22:32:08 2014 ORA-09341: scumnt: unable to mount database OSD-04400: unable to acquire internal semaphore for process

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Exadata Storage Server Version 12.1.1.1.0 Released

Oracle has released the much-anticipated version of cellsrv compatible with Oracle Database 12.1.0.1 (patch #16980054). Before thinking about upgrading, read MOS note #1571789.1 carefully.  Unless you are planning to run database 12c on your Exadata, it would be advisable to continue down the 11.2 branch (more...)

Oracle Announces Exadata X4-2

Today, Oracle announced the Exadata X4-2 model.  The X4 has some considerable improvements, namely:

  • 12-core Intel Xeon e5-2697 CPUs, up from the 8-core models found in the X3-2 (hello, database licenses!)
  • 256GB RAM per database server, upgradeable to 512GB
  • 96GB RAM per storage server
  • 800GB Sun Flash F80 cards (more...)

OSP #2c: Build a Standard Platform from the Bottom-Up

This is the fourth of twelve articles in a series called Operationally Scalable Practices. The first article gives an introduction and the second article contains a general overview. In short, this series suggests a comprehensive and cogent blueprint to best position organizations and DBAs for growth.

This article – building (more...)

Stuck Timezone Upgrades and Smart Scans

I heard a strange report from a client late last week - they weren't getting any smart scans on their Exadata - a data warehouse, no less (and we checked to see if cell_offload_processing was set to true).  Queries would run normally, but for some reason, the "cell physical IO (more...)

Tightening Security with SELECT ANY DICTIONARY in Oracle 12c

Developers and users sometimes request the SELECT ANY DICTIONARY system privilege to enable them to view various data dictionary tables.  This may be fine for querying DBA_TABLES, etc, but the Oracle data dictionary contains a LOT of information.  Some of the views/tables are compromising from a security standpoint. (more...)

Data Pump 12c – Pumping Data with the LOGTIME Parameter

Since its release, Oracle Data Pump has been a worthy successor to the traditional exp/imp tools.  However, one area lacking with Data Pump has been something as simple as the ability to identify how long each step of a Data Pump job actually takes.  The log will show (more...)

Oracle 12c – Out With the Grid, In With the Cloud

So Oracle database 12c is out now.  The cloud (and hence the “c”) is hanging over us.  At least we don’t have to hear about “the grid” anymore.  New versions of Oracle are funny things – as DBAs, we’re kinda excited about the possibilities, but then reality (more...)

12c: Sqlplus Displays Last Login Time For Non – Sys Users

Original Post can be viewed at 12c: Sqlplus Displays Last Login Time For Non – Sys Users

12c database has introduces a pretty nifty Security feature which allows you to check last login time for non-sys user. e.g If I connect to scott user as below, it displays that (more...)

Oracle 12c has arrived

I really didn't think we would be seeing 12c until OpenWorld. I got a nice surprise a couple of weeks ago when people started tweeting that the docs were out. That followed quickly with the actual software being available for download.

 

I realize that people won't really be producing (more...)

12c:Limiting PGA with pga_aggregate_limit

Original Post can be viewed at 12c:Limiting PGA with pga_aggregate_limit

This is a interesting feature for Oracle DBA’s. Till now there has been no way of limiting total PGA being used by oracle instance. _pga_max_size (hidden parameter) could be used to limit per process memory. SGA_TARGET used to be hard (more...)

Oracle database 12c

So there is a new toy in the market for database geeks : Oracle has released database 12c. Every social platform is abuzz with the 12c activity. So thought that I should also complete the ritual Winking smile

In this post Aman has already summed up many important links.

Maria Colgan has (more...)

Required Reading

It's not often that I run across articles that really resonate with me. Last night was one of those rare occasions. What follows is a sampling of what I consider to be required reading for any IT professional with a slant towards database development.

Bad CaRMa

Oracle Database Gateways 11g R2 (11.2) Installation and Configuration for heterogeneous connection from Oracle to Microsoft SQL database

Installation

Install the Oracle Database Gateways 11g R2 (11.2). See the screen snapshots of the installation here.

Configuration

  • During the installation, the following+ default initialization parameter file is created:
[ORACLE_DG_HOME]dg4msqladmininitdg4msql.ora
dg4msql = Database gateway for Microsoft SQL Server. 
If you choose a different database option, use the appropriate path name.
  • Copy initdg4msql.ora to a new file init[MSSQL].ora.
[MSSQL] can be any meaningful name easier to refer to,  (more...)

When to consider sharding a MySQL database

Uncategorized
| Mar 13, 2013

When to consider sharding a MySQL database

 

Why should you not just design your applications from the start to account for data sharding? Sharding a database, that is horizontally partitioning tables among multiple databases, creates an added level of complexity that is not desirable in an application. However, there are times when sharding is required to maintain acceptable performance. So when is the right time to shard your database?

 

When to consider sharding a MySQL database   Why should you not just design your applications from the start to account for data sharding? Sharding a database, that is horizontally partitioning tables among multiple databases, creates an added level of complexity that is not desirable in an application. However, there are times when sharding is […]

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Schema and User 101

Uncategorized
| Jan 22, 2013

Schemas and users are frequently used interchangeably as if they were the same thing. For the most part, that's ok. In Oracle the concepts are so tightly coupled that thinking of them as the same thing is not really that far wrong. 


In reality, a user is a database account that is given a password and permissions. A schema is a container, or namespace, for containing schema objects. Schema objects are things like tables, views and indexes.


In Oracle, when a us

How long did Oracle materialized view refresh run?

The LAST_REFRESH_DATE column of the DBA_MVIEWS or the LAST_REFRESH column of the DBA_MVIEW_REFRESH_TIMES indicates the start refresh time. But what if we’d like to find out how long the refresh of the materialized view really takes. Well, we can query the DBA_MVIEW_ANALYSIS.

For Complete Refresh, the refresh duration will be in the FULLREFRESHTIM column of the DBA_MVIEW_ANALYSIS. For Fast Refresh duration, it will be in the INCREFRESHTIM column.

Both values are in seconds.

SELECT mview_name,  (more...)