Annonce : Workshop DBaaS

Un workshop sur le sujet DBaaS, à destination des partenaires Oracle, aura lieu le 4 et 5 mars à Colombes (France)
Plus de détails : http://eventreg.oracle.com/profile/web/index.cfm?PKWebId=0x1713052088

MySQL Locking

Have you ever wondered if MySQL does Row Level Locking? Or wondered why are you getting the error:

ERROR 1205 (HY000) : Lock wait timeout exceeded; try restarting transaction

You get the error because your allocated time to hold a DML lock in a transaction exceeds the set limit. Usually the default limit to hold a DML row lock, set by innodb_lock_wait_timeout db parameter, is 50 seconds. If your transaction doesn't commit/rollback within 50 seconds (more...)

DBMS_SCHEDULER jobs running an hour late – DST/BST issues!

This week one of our developers highlighted the fact that the DBMS_SCHEDULER on one of our 11.2.0.3 databases was running jobs an hour later than scheduled until just recently, when the clocks went back (26/10/2014) for British Summer Time (BST) …and now they’re running on-time again! I’d not seen this before, and at first I thought we

Read More...

Patching Time

Just a quick note to point out that the October PSU was just released. The database has a few more vulnerabilities than usual (31), but they are mostly related to Java and the high CVSS score of 9 only applies to people running Oracle on windows. (On other operating systems, the highest score is 6.5.)

I did happen to glance at the announcement on the security blog, and I thought this short (more...)

Move That Datafile!

Moving datafiles has always been a pain.  There are several steps, it’s fairly easy to make a mistake and it requires the datafile to be offline.  There are also different steps depending on whether the database is in ARCHIVELOG mode or not.  In ARCHIVELOG mode, the steps are…

1)      Take the tablespace containing the datafile offline
2)      Copy/rename the datafile at the OS layer
3)      Use ALTER TABLESPACE…RENAME DATAFILE (more...)

Oracle 12c – New SYS-level Administration Privileges

For a while now, Oracle has been moving its security model toward a more differentiated set of privileges than just SYSDBA and SYSOPER.  We saw this in 11g with the SYSASM privilege.  This is in response to the growing number of DBA shops that delineate permissions at a more granular level, even among DBAs.  Rather than saying, “Here’s my DBA team, everyone has SYSDBA,” more and more IT shops are defining DBA (more...)

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

Read More...

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

Read 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 […]

-->