Log file sync from neither I/O nor CPU

Two most popular causes for log file sync waits are redo filesystem I/O and CPU (or CPU scheduling). I’d like to share an example of a third scenario.

A few days ago, I noticed a weird spike in log file sync average duration on a production 11.2 database:

select time,
       snap_id,
       round(time_delta/1e3/nullif(waits_delta,0), 1) avg_wait_ms,
       waits_delta num_of_waits,
       round(time_delta/1e6) total_seconds
from
(       
  select sn.snap_id,
         sn.begin_interval_time time,
         e.total_waits - lag(e.total_waits) over (partition by e.event_name  (more...)

Poor Man’s In-Memory Caching

Introduction

It is common knowledge, or at least it should be, that Oracle has
released version 12.1.0.2 in June 2014. which has a feature called
“Oracle In-Memory”. The name is a tad confusing, since many
features were called “in-memory” before, from “Very Large
Memory” to Times 10 product.

This “In Memory” option is a licensed product featuring
columnar storage, in addition to the normal buffer storage, almost
identical to IBM’s “Blu acceleration” (more...)

Openworld

Well, the annual spectacle of enormous proportions has come to a conclusion again. And thats probably the first reason I’d recommend OpenWorld to anyone who works with Oracle who has never been to it. It’s a jaw dropping moment just to see the scale of the event, and how impressively its organised in terms of facilities, lunches, registration and the like.

But onto the technical elements, here’s my impressions of this years conference:

1) Big (more...)

Slides from OakTableWorld and OpenWorld

Thanks to anyone that came along to my sessions at OpenWorld.

You can review the slides via the links below:

http://www.slideshare.net/hamcdc/oaktable-world-sep14-clonedb

http://www.slideshare.net/hamcdc/openworld-sep14-12c-fordevelopers

 


Larry’s OOW Keynote on the future of Oracle Applications

larry2Although there had been many analyst and Oracle ACE briefings for much of the preceding week, Sunday night was the ‘proper’ opening for Oracle OpenWorld 2014. It kicked off with Larry’s first keynote of the conference. (He traditionally does two, however skipped the second last year to watch the thrilling finale to the 2013 America’s Cup.)

His hour long address was given over exclusively to the cloud. Here’s a summary of the important points (more...)

Talend: Schema compatibility check

Most of the time when talking about Talend jobs, people think of standard ETL (Extract, Transform, Load). But in some cases there’s the need to check the incoming data before loading them into the target rather than just transforming it. We refer to this process as E-DQ-L (Extract, Data Quality, Load).

One of the things that you might want to check before loading is schema compatibility. (more...)

Patch 19183482 resolves ORA-01403 getting plan with baseline

I was testing SQL plan baselines on a base 11.2.0.3 release of Oracle on a 64 bit Linux virtual machine.  I ran DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE to create a SQL plan baseline for a test query after running that query once to get its plan in the cursor cache.  When I ran the test query after creating the SQL plan baseline and called dbms_xplan.display_cursor to see its new plan I got (more...)

Preparing for Oracle OpenWorld

The big annual Oracle event is almost here – starting Sunday 28 Sep with the User Group Sunday followed by four days of presentations in around 50 tracks!

If the agenda seems a bit overwhelming, read the OTech Magazine Special OpenWorld Issue to find some of the highlights and can’t-miss sessions.

My sessions are:

  • Mastering Oracle ADF Bindings: Advanced Techniques (UGF3484). Sunday Sep 28 at 10am in Moscone South room 270
  • Starting Your Oracle Application (more...)

On the Topic of Technology… 7

September 26, 2014 (Back to the Previous Post in the Series) As I was walking from the back of the facility where I work to my office just recently, I started repeatedly saying to myself as I approached the office door, “that huge computer was not here when I started calling my office a second home“.  I […]

Where the real technical talks are at OOW

What are the real technical talks at OOW amid all the marketing fluff? I don’t know all of them but I can vouch for the following

 

time id speaker room title
Sunday 9:00 UGF2563 Jeremiah Wilton, Marc Fielding M South 309 24/7 Availability with Oracle Database Application Continuity
9:00 UGF4378 Gwen Shapira M South 308 Analyzing Twitter Data with Hadoop – Live Demo
10:00 UGF3587 Tim Gorman M South 301 Scaling To Infinity: Partitioning (more...)

Query to show sql_ids related to SQL Profiles

I have a number 0f SQL Profiles on a database I’m working on and I wanted to know the sql_id of the SQL statements that they relate to.  Here is what I came up with:

select distinct 
p.name sql_profile_name,
s.sql_id
from 
dba_sql_profiles p,
DBA_HIST_SQLSTAT s
where
p.name=s.sql_profile;

Here is the output on my system:

SQL_PROFILE_NAME               SQL_ID
------------------------------ -------------
coe_5up1944u1zb7r_1979920644   5up1944u1zb7r
coe_b9ad7h2rvtxwf_3569562598   b9ad7h2rvtxwf
coe_9f21udzrfcygh_2815756405   9f21udzrfcygh
coe_366brswtxxuct_10194574     366brswtxxuct
coe_2261y37rp45py_2815756405   2261y37rp45py

These are (more...)

Openworld day minus 3

Its day minus 3, or day +1 depending on your point of view at Openworld 2014.

I’m here a few days early for the Ace Director briefings, where a selection of product managers provide an insight into what is coming in the Oracle world, either at Openworld or in the coming year.

I must admit, I arrived to the briefings somewhat sceptical because a couple of years ago, when I was last at the briefings, (more...)

Oaktable World & Delphix Labs on Mon & Tues

Next week during Oracle Open World, be sure and come on Monday and Tuesday to the free Oaktable World and  on Tuesday to Delphix hands on lab and free 90 day trial version at #CloneAttack at the same venue as Oaktable World.   The labs will also be joined by DBvisit for #RepAttack and Solarwinds (Confio) for #MonitorAttack.

 

Screen Shot 2014-09-12 at 12.38.32 PM

Screen Shot 2014-09-25 at 8.30.39 AM

Beer, Meat, Explode

 

Screen Shot 2014-09-15 at 10.57.34 AM

 

Screen Shot 2014-09-15 at 10.57.41 AM

Screen Shot 2014-09-22 at 7.18.15 AM

 

 

My Data Model Checklist book is now available in Spanish – Just in time for #OOW14!

Originally posted on Oracle Data Warrior:

Exciting news!

I just got this email from Amazon:

Congratulations, your book “UNA LISTA DE VERIFICACIÓN PARA REALIZAR REVISIONES A LOS DISEÑOS DE MODELOS DE DATOS” is live in the Kindle Store and is currently enrolled in KDP Select. It is available for readers to purchase here.

If you are in Mexico, you can get the book here.

If you are in Spain, you can get it here.

(more...)

Oracle Open World schedule

Here is my schedule of presentations at Open World this coming week.

I most excite about my talk on Sunday. The Phoenix Project is a awesome book everyone should read, DevOps is the rising star of IT and this talk will empower DBAs to take their careers to the next level with data virtualization – virtualize, govern and deliver data efficiently boosting your companies efficiencies and bottom line much greater than any other change one could make (more...)

Startup upgrade suppresses ORA-00955 on create table WRH$_SQL_PLAN

Today I was trying to see if upgrading from 11.2.0.2 to 11.2.0.4 would change the SYS.WRH$_SQL_PLAN table.  This table is large on our production system so I wanted to find out if some time-consuming update to this table would occur that would slow down our production upgrade but not be detected on our test systems.  We recently performed this upgrade on our development database and I (more...)

Delphix trial version available for first time : #CloneAttack

At Oracle Open World we will be leading hands on labs to install a fully operation Delphix environment on your laptop.

The labs will be hosted at the Creativity Museum, the same location as Oaktable World on Tuesday Sept 30 from 10am to 5pm. Solarwinds Confio and DBvisit will also beholding #MonitorAttack and #RepAttack in the same location.

The labs for Delphix will be led by

Jonathan Lewis explains Delphix internals

Last week we had a great webinar with Jonathan Lewis as he explained his hands on experience of Delphix, how Delphix works internally and some use cases that Delphix solves for Jonathan.

Jonathan will be joining us a the Delphix booth at Oracle Open World and giving shorter version of the presentation at 10am on Monday and Tuesday and 11am on Wednesday.

Also Jonathan will be speaking at Oaktable World on both Monday 1pm and (more...)

Oracle Forms 12c?

Some people wonder whether there will be a 12c version of Oracle Forms or not.

Instead of making guesses, the best way is to ask the people who know best.
So, after getting this question, I asked Michael Ferrante, Oracle Forms Product manager.

Here’s his answer:

Version 12 of Forms and Reports is tentatively planned for releases sometime in CY2015.  At this time, we (Oracle) are not permitted to share exact dates, but (more...)

High log file sync waits? Check log parallelism!

Log parallelism is an optimization introduced in 9.2 that reduces latch contention due to redo copy to the log buffer by enabling multiple public redo buffers (or “strands”). In many cases, however, it can cause a massive degradation of commit performance (“log file sync” wait increase). In this blog post, I will describe the mechanism, illustrate it with test results, and discuss solutions. Tests were performed on several different 11gR2 databases on Solaris servers.

Log parallelism

Log parallelism is controlled by (more...)