The blog has moved

October 26, 2009 Leave a comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de

Categories: Oracle in general

Backing up your system configuration

October 21, 2009 Leave a comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de


When backing up servers with any kind of backup software you will most certainly backup your data.

But how about the system configuration?

When restoring a system from scratch do you know how big the disks were, what partition sizes, what disks used (in case you have more than one disk), if you used an LVM and so on.

Think about it!

In this article i wanted to summarize what system information should be collected to enable a fast and error free restore.

Feel free to add your own comments and suggestions.

Read more…

Categories: Oracle in general

Oracle on linux – yes of course – but what linux?

October 19, 2009 Leave a comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de


There is a discussion from December 2008 what Linux (SLES vs. Red vHat vs. Oracle Enterprise Linux) to use for running oracle on Linux by Yann Neuhaus. You can read his post here.

After nearly one year i wanted to catch up the article and check if the pros and cons are still valid or if there changed anything.

Read more…

Categories: Oracle in general

ORA-01555 (snapshot too old) error although undo_retention set to a high value

October 17, 2009 1 comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de

The past week i had a argumentation with a colleague of mine on the behavior of the parameter undo_retention in 10g.

He stated in 10g undo_retention determines the lower number of seconds oracle keeps the undo records. If there is enough space available an ORA-01555 should not be raised.

I knew there are cases in which undo_retention is set to a ridiculous high value (for instance a week), the undo tablespace has a lot of free space but an ORA-01555 is raised nonetheless. So we took a look at the documentation:

For Oracle 10g Release 1 the documentation states:

UNDO_RETENTION specifies (in seconds) the low threshold value of undo retention. The system retains undo for at least the time specified in this parameter and automatically tunes the undo retention period to satisfy the undo requirements of the queries.

But for Oracle 10g Release 2 the documentation says different:

UNDO_RETENTION specifies (in seconds) the low threshold value of undo retention. For AUTOEXTEND undo tablespaces, the system retains undo for at least the time specified in this parameter, and automatically tunes the undo retention period to satisfy the undo requirements of the queries. For fixed- size undo tablespaces, the system automatically tunes for the maximum possible undo retention period, based on undo tablespace size and usage history, and ignores UNDO_RETENTION unless retention guarantee is enabled.

In Oracle 11g Release 1 and Oracle 11g Release 2 the behavior is the same as for Oracle 10g Release 2.

Categories: Oracle in general

11g Release 2 release rumors

October 16, 2009 Leave a comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de

There are rumors on the release dates of 11.2.0.1.0 for different plattforms. According to my information the release dates are:

  • Windows: second quarter 2010
  • Linux: already released (32-bit and 64-bit intel)
  • HP-UX: 4th quarter 2009
  • Solaris: 4th quarter 2009
  • AIX 5L based: 4th quarter 2009

I personally expect the release of 11g Release 2 for solaris operating system pretty soon.

Categories: Oracle in general

Data Pump falsely reports the number of imported rows as 1 (one)

October 16, 2009 Leave a comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de

Yesterday i did a large import using data pump and the network mode feature. I noticed a table containing a large number of rows were reported by data pump as imported but with only one (1) row.

First i checked my import options, checked for errors in source and target database and even cleaned up everything and restarted the import. Surprise surprise: Same error again.

The environment was:

  • Oracle Enterprise Edition 10.2.0.4.0
  • Solaris (SPARC) 10
  • Data Pump Import with NETWORK_MODE
  • excluding STATISTICS, GRANTS and ROLE_GRANTS

Extract  from the data pump log file:

Processing object type SCHEMA_EXPORT/CLUSTER/CLUSTER
 Processing object type SCHEMA_EXPORT/CLUSTER/INDEX
 Processing object type SCHEMA_EXPORT/TABLE/TABLE
 . . imported "USER"."TABLE_A"                 55082451 rows
 . . imported "USER"."SOME_LARGE_TABLE"       307126916 rows
 . . imported "USER"."ANOTHER_TABLE"          176936257 rows
 . . imported "USER"."JUST_ANOTHER_TABLE"     215682029 rows
 . . imported "USER"."HUGE_TABLE"                     1 rows        <====
 . . imported "USER"."AND_SO_ON"              133356302 rows

So i started to dig a little bit deeper and noticed the source table has approx 62 million rows with a size of 28 GB. To my surprise the target database also reported the table with 28 gb in DBA_SEGMENTS.

So i did a simple:

SQL> select count(1) from user.huge_table;
COUNT(1)
 ----------
 62485290

Guess what? The table was imported correctly with all rows while data pump reported only one imported row.

I check metalink for related errors but found nothing.

I can only guess if this is a bug or there is some time limit when querying the rows of the just imported tables.

Update: I did some reseach and created a really large table with 1 billion rows the data pump showed:

. . imported "USER"."TABLE_WITH_1_BILLION_ROWS"             -1416726547 rows

There might be some kind of counter overflow…. i will investiage this further.

Categories: Oracle in general

New public oracle yum server

October 15, 2009 1 comment

Dear Readers,

my blog has moved to a different server.

The new address is:

http://blog.ronnyegner-consulting.de

I just found a new public yum server hosted by oracle. This server can be used to install missing packages over the internet. It does not contain any security updates or bug fixes.

The public yum server can be found here.

For larger installation you can run your own yum server.

Categories: Oracle in general