Parse Time

Here’s a little query I wrote some time ago to see where my time went while running a query. It’s nothing sophisticated, just one of those simple things you can do with v$active_session_history (or dba_hist_active_sess_history, if you don’t get to the crime scene in time).


set null CPU

select
        sql_exec_id, in_parse, in_hard_parse, event, count(*)
from
        v$active_session_history
where
        sql_id = '{your choice here}'
group by
        sql_exec_id, in_parse, in_hard_parse, event
order by
        sql_exec_id, in_parse, in_hard_parse, count(*)
 (more...)

ORA-00600 [kdiRelocateCommitted:DBAupd]

This error recently showed up in a 11.2.0.3.0 Enterprise Edition RDBMS on Oracle Enterprise Linux: ORA-00600: internal error code, arguments: [kdiRelocateCommitted:DBAupd], [2126573183], [], [], [], [], [], [], [], [],
[], []
Incident details in: /u01/app/oracle/diag/rdbms/ ....._ora_5642_i10412.trc

After the trace file I was able to identify which operation produced the error and identify the specific partition that had problems.  The error was triggered during a partitioned index maintenance operation:

alter (more...)

Making sense out of optimizer trace files

Sometimes the optimizer makes really odd decisions. We can use optimizer (“event 10053″) tracing to obtain clues as to why such decisions were taken, but it’s not simple. First, such trace files tend to be big. Second, they don’t always contain the necessary information. There is a simple trick that can be useful in such cases.

First, I use “optimizer_features_enable” hint to try and find Oracle version where the logic changes. Of course, I don’t (more...)

10128 trace to see partition pruning

I am working on an SR with Oracle support and they asked me to do a 10128 trace to look at how the optimizer is doing partition pruning.  I did some quick research on this trace and wanted to pass it along.

Here are the names of the two Oracle support documents that I found most helpful:

How to see Partition Pruning Occurred? (Doc ID 166118.1)

Partition Pruning Min/Max Optimization Fails when Parallel (more...)

Riga Dev Day 2015

Over the weekend I booked my flights and hotel for the Riga Dev Day on January 22nd.

It’s my first time in Latvia, so I look forward to seeing everyone out there!

Cheers

Tim..


Riga Dev Day 2015 was first posted on December 9, 2014 at 2:09 pm.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If you are not reading this article in your feed reader, (more...)

Oracle ACE Program : Thanks Folks!

As you will know from my previous post, I picked up the “UK Speaker Award” at UKOUG Tech 14. I’ve already  done a bunch of thank you messages, but I’d just like to take a minute and thank the Oracle ACE Program for they part they have played in this.

Many of you will know, I was invited to the ACE program because of my online contributions to the Oracle community. Prior to joining (more...)

UKOUG Tech 14 : Monday

The day started with a taxi ride into New Street station to get the 06:01 train to Liverpool Lime Street. I was a little dissapointed that the train was a sprint train, so there were no tables and no power sockets. When the ticket guy came through I asked about an upgrade to first class and it was only £25 for the return journey, so I paid the extra to get a table and a (more...)

UKOUG Tech14 slides – Exadata Security Best Practices

I think 2 years is long enough to wait between posts!

Today I delivered a session about Oracle Exadata Database Machine Best Practices and promised to post the slides for it (though no one asked about them :). I’ve also posted them to the Tech14 agenda as well.

Direct download: UKOUG Tech14 Exadata Security slides

Day 1 of UKOUG Tech 14

Monday was the first day of the main part of the UKOUG Tech 14 conference, after SuperSunday’s additional content. I had a great night’s sleep and woke at 7 am, much to the disgust of Richard Foote who had been up for four hours already and didn’t seem to appreciate my #NoJetLagHere hashtag replying to his lack of sleep tweet. :) I managed to get to the conference relatively dry, but realized yet again that you (more...)

Changing The Number Of Oracle Database 12c Log Writers

Changing The Number Of Oracle Database 12c Log Writers


In an Oracle Database 12c instance you will likely see multiple log writer (LGWR) background processes. When you first start the Oracle instance you will likely see a parent and two redo workers. This is a very big deal and something many of us have been waiting for - for many years!

While I'm excited about the change, if I can't control the number of LGWRs (more...)

Cardinality Change

Here’s an entertaining little change across versions of Oracle, brought to my attention by Tony Hasler during UKOUG Tech 14. It’s a join cardinality estimate, so here are a couple of tables to demonstrate the issue – the only columns needed are the alpha_06 columns, but I reused some code from other demonstrations to create my test case, so there are lots of irrelevant columns in the create table script:


create table t1 nologging as
with generator as (
         (more...)

Repost: Oracle Trivia Quiz

All the answers to the quiz are in the November 2014 issue of the NoCOUG Journal . I am the editor of the NoCOUG Journal. What’s NoCOUG, you ask? Only the oldest and most active Oracle users group in the world. If you have not attended a NoCOUG conference in the last 28 years—yes that’s how long NoCOUG has been around—you can attend the winter conference on January 27 for free subject to availability of free (more...)

You Can Get There Making All Right-Hand Turns But …

It would appear that some DBAs are still using the optimizer_index_cost_adj parameter to make index access paths more ‘desirable’ to the optimizer. In decades past this might have been a good strategy however with the improvement in statistics gathering in recent relesaes of Oracle this might not be the case. Let’s look at an example to see why this might do more ‘harm’ than good.

The optimizer_index_cost_adj parameter was first provided in Oracle 9i as (more...)

Agile Morning

You may have noticed some tweets from me on Friday morning on the subject of Agile methodologies. Work arranged for a couple of speakers to come in to speak to us on the subject.

Our company is made up of three types of people.

  • Those that are full invested in agile and use it on a day-to-dat basis.
  • Those that think they know agile and perform some bastardised version of it.
  • Those that need a (more...)

Days -1 and 0 of UKOUG Tech 14

The UKOUG user group conference is one conference I have wanted to get to for a long time, but never managed to before. This year, with the change in job roles to being a database architect in the DBaaS team within the Enterprise Manager product management group, I finally got the go ahead to submit some papers. I was notified some time back that one of them had been accepted (Snap Clone) and one shortlisted (more...)

ASM DiskGroup Performance Statistics

The V$ASM_DISKGROUP_STAT view provides 12c ASM DiskGroup Performance Statistics for current DiskGroups. The data is extracted from the X$KFGRP_STAT source table. This view like all other ASM views are available in both the ASM and the Database instance. The data for this view accessed from the ASM includes information for all databases connected to the […]

The post ASM DiskGroup Performance Statistics appeared first on VitalSoftTech.

Turkish Hadoop User Group(TRHUG) 2014 meeting

Turkish Hadoop User Group(TRHUG) 2014 annual meeting will be at Monday December 22, Levent İstanbul. Microsoft TR is the sponsor of the meeting this year. Turkcell has two slots on the agenda this year; one on an interesting project called Curio based on Kafka, Storm and Cassandra the real-time side of the ecosystem. The other […]

Segment Creation Deferred and ORA-02266

If you try to truncate a table with a primary key which is referenced by an enabled foreign key, you usually get an ORA-02266 error. This happens straight away if the table is set up with segment creation immediate. However, if the table is set up with segment creation deferred, the error is not reported until the segment has been created. You can see what I mean in the example below, which I tested (more...)

Join Us For a Networking Event at UKOUG

UKOUG event photo

Join us for an informal networking event alongside Rittman Mead on Monday December 8th during UKOUG. We will be discussing how to leverage data to drive your organization’s success. Come meet with peers and industry experts, Mark Rittman and Jon Mead of Rittman Mead, and Marc Fielding and Christo Kutrovsky of Pythian. The networking event will take place at PanAm Bar and Restaurant in Liverpool from 6-8 PM, and will include drinks and light (more...)

UKOUG Tech 14

On Sunday I will be heading North from London to Liverpool for 4 days, to attend another UK Oracle User Group conference – #UKOUG_Tech14

I’m sure it will be as wonderful and informative a 4 days as you can get in the Oracle technical area. The hard part of attending is working out what and who to see.

I will be presenting there again – this time a talk on Goldengate late on the final (more...)