I’m not very keen on bending the rules on production systems, I’d prefer to do things that look as if they could have happened in a completely legal fashion, but sometimes it’s necessary to abuse the system and here’s an example to demonstrate the point. I’ve got a simple SQL statement consisting of nothing more than an eight table join where the optimizer (on the various versions I’ve tested, including 12c) examines 5,040 join orders (even though _optimizer_max_permutations (more...)
This is a growing high quality regional conference in Cleveland where we are hoping to pass 350 ( 400? ) in attendance this year. We have Kerry Osborne and Steven Feuerstein doing keynotes and on Monday 1/2 day workshops before the conference kicks into high (more...)
While I was away on the OTN APAC tour, I wasn’t really able to sink my teeth into anything, so inspired by Connor McDonald‘s session in Perth, I decided to write up a few bits and pieces in my free moments in the hotels and planes (when I had enough elbow room to type).
Here is what I’ve neatened up so far.
As you will have seen from my last post, I’m back in Birmingham after completing the OTN APAC 2014 tour. Here is a list of all the posts I wrote over the course of the tour.
Everything went smoothly at Auckland airport. Boarding an A380 takes quite a bit of time and I was near the front of the plane, so I was in the last group to board. Fortunately there was loads of room for hand luggage and the seat was pretty good. The people too my right were a couple, so they were leaning together, which gave me more elbow room. The extra room and a plug socket meant (more...)
I will start this post off stating that I know there are better and more efficient methods of doing this but this is the best method I could come up with.
I had a csv file with a number of columns, one of which was data in a timestamp with timezone format.
A few rows looked like this – note I have stripped the other columns out for ease of display.
7941 11/9/2014 (more...)
Just got home to find VirtualBox 4.3.20 has been released. I’ve just installed it on MaC (Yosemite), Fedora 20 and Windows 7 with no dramas so far.
VirtualBox 4.3.20 was first posted on November 22, 2014 at 4:11 pm.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If you are not reading (more...)
In the Oracle RAC previous version we have worked with the option “misscount” of crsctl, which applies for all the servers because there was only one kind of servers, but in the new version of Oracle (12c) we have a new kind of RAC configuration, the “Flex Cluster”. With Flex Cluster we have two kinds of servers “Hub nodes” and “Leaf Nodes”, the Hub Nodes have the same concept of the normal nodes in the previous versions, however (more...)
Just wanted to share some pieces of information from the recent DOAG annual conference that you may find interesting.
From Mike Dietrich’s presentation about Database Upgrade:
Database Replay is extremely useful to predict after-upgrade performance on a test system,
especially we can record the production load on 10g even.
From Carsten Czarski’s talk about XML DB:
With 12c, XML DB is mandatory and it provides an easy way to upload BLOBs via ftp into the (more...)
While creating a POC of a SQL rewrite recently I received a little surprise as I switched my query from serial execution to parallel execution and saw the optimizer’s estimated cost increase dramatically. I’ll explain why in a moment, but it made me think it might be worth setting up a very simple demonstration of the anomaly. I created a table t1 by copying view all_source – which happened to give me a table with about 100,000 rows and 1117 (more...)
I know some people share my opinion on this and others totally disagree – but I fail to appreciate why people I have never met, spoken with or care about want to Social Media with me. If we have not met but there is a high probability we share unusual interests then OK, perhaps – but the fact that we both can spell Oracle or know what a gene is does not count as unusual (more...)
APPEND hint in oracle is very useful, there are many benefits
Fragmented data loading – data will clustered above the HWM so that similar data will be together. Otherwise Oracle will place the records in blocks using PCT_FREE rule
- No undo will be generated – in large direct path insert will free up large amount of data blocks
- Less CBC latches (because of no UNDO blocks), less CPU usage
- Readers need not undo the records, (more...)
My day 2 at the conference started with my analytic functions session. I’m always a bit worried I oversimplify things, but people seem to appreciate it, so perhaps I’m just being paranoid. I’m sure the feedback will let me know.
Next I went to Chris Muir‘s session of Developing Web and Mobile Dashboards with Oracle ADF. I had already seen this at the AUSOUG WA event in Perth, but I liked it, so I (more...)
I got a bunch of emails this morning telling me by blogs had upgraded to WordPress 4.0.1. It’s a critical security release, so if you’ve not done an auto-update, you really need to get this sorted.
WordPress 4.0.1 Released was first posted on November 20, 2014 at 11:32 pm.
©2012 "The ORACLE-BASE Blog". Use of this feed is (more...)
Just a quick blog post on things you might see after upgrading to 126.96.36.199. We recently upgraded database from 188.8.131.52 to 184.108.40.206 and query on some data dictionary views ran too slow.
1. Performace of query on dba_free_space degraded
2. Performance of query involving dba_segments is slow
DEV01> select ceil(sum(b.bytes)/1024/1024) b from sys.dba_free_space b; Elapsed: 01:31:45.78
Searching MOS pointed to these Doc Ids (more...)
An interesting experience I have had this year is being more involved in helping organise the annual UKOUG Oracle Technical Conference – Tech14 this year. I fully intended to blog about things as we progressed, but it never happened. But I thought it would be interesting to do a couple of blogs about it, for anyone interested,
If you have never helped organise a conference or user group meeting then you probably think there is (more...)