It's webinar time again.
Join me on Wednesday, January 28th at AllThingsOracle.com
for a session based on a real world customer experience.
The session starts at 3pm UK (16:00 Central European) time. The webinar is totally free and the recording will made available afterwards.
Here's the link to the official landing page
where you can register and below is the official abstract:
After a short introduction into what the Oracle Exadata Database Machine (more...)
Many people have asked me this question that how they can learn Exadata ? It starts sounding even more difficult as a lot of people don’t have access to Exadata environments. So thought about writing a small post on the same.
It actually is not as difficult as it sounds. There are a lot of really good resources available from where you can learn about Exadata architecture and the things that work differently from any non-Exadata (more...)
Recently we’ve seen a strange problem with the deadlocks at the client database on Exadata, Oracle version 22.214.171.124 . Wait events analysis showed that sessions were waiting for “enq: TX – allocate ITL entry” event. It was strange because there are at most two sessions making DMLs and at least two ITL slots are available in the affected tables blocks. I made some block dumps and found that affected blocks contain the OLTP-compressed (more...)
Every DBA working with the Oracle database must have seen memory dumps in tracefiles. It is present in ORA-600 (internal error) ORA-7445 (operating system error), system state dumps, process state dumps and a lot of other dumps.
This is how it looks likes:
Dump of memory from 0x00007F06BF9A9E00 to 0x00007F06BF9ADE00
7F06BF9A9E00 0000C215 0000001F 00000CC1 0401FFFF [................]
7F06BF9A9E10 000032F3 00010003 00000002 442B0000 [.2............+D]
7F06BF9A9E20 2F415441 31323156 4F2F3230 4E494C4E [ATA/V12102/ONLIN]
7F06BF9A9E30 474F4C45 6F72672F 315F7075 (more...)
I’ve spent a few days playing with patching 126.96.36.199 with the so called “Database Patch for Engineered Systems and Database In-Memory”. Lets skip over why these not necessarily related feature sets should be bundled together into effectively a Bundle Patch.
First I was testing going from 188.8.131.52.1 to BP2 or 184.108.40.206.2. Then as soon as I’d done that of course BP3 was released.
This is the 4th post in a series of posts on PGA behaviour of Oracle. Earlier posts are: here (PGA limiting for Oracle 12), here (PGA limiting for Oracle 11.2) and the quiz on using PGA with AMM, into which this blogpost dives deeper.
As laid out in the quiz blogpost, I have a database with the following specifics:
-Oracle Linux x86_64 6u6.
-Oracle database 220.127.116.11 PSU 4
This is a series of blogposts on how the Oracle database makes use of PGA. Earlier posts can be found here (PGA limiting for Oracle 12) and here (PGA limiting for Oracle 11.2).
Today a little wednesday fun: a quiz.
What do you think will happen in the following situation:
-Oracle Linux x86_64 6u6.
-Oracle database 18.104.22.168 PSU 4
-Oracle database (single instance) with the following parameter set: memory_target=1G. No other (more...)
This is the second part of a series of blogpost on Oracle database PGA usage. See the first part here. The first part described SGA and PGA usage, their distinction (SGA being static, PGA being variable), the problem (no limitation for PGA allocations outside of sort, hash and bitmap memory), a resolution for Oracle 12 (PGA_AGGREGATE_LIMIT), and some specifics about that (it doesn’t look like a very hard limit).
But this leaves out Oracle version (more...)
This post is about memory management on the operating system level of an Oracle database. The first question that might pop in your head is: isn’t this a solved problem? The answer is: yes, if you use Oracle’s AMM (Automatic Memory Management) feature, which let’s you set a limit for the Oracle datababase’s two main memory area’s: SGA and PGA. But in my opinion any serious, real life, usage of an Oracle database on Linux (more...)
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
With the INMEMORY clause you can specify 4 sub-clauses:
- The MEMCOMPRESS clause specifies whether and how compression is used
- The PRIORITY clause specifies the priority (“order”) in which the segments are loaded when the IMCS is populated
- The DISTRIBUTE clause specifies how data is distributed across RAC instances
- The DUPLICATE clause specifies whether and how data is duplicated across RAC instances
The aim of this post is not to describe these attribues in detail. Instead, (more...)
In Part I, I discussed how Zone Maps are new index like structures, similar to Exadata Storage Indexes, that enables the “pruning” of disk blocks during accesses of the table by storing the min and max values of selected columns for each “zone” of a table. A Zone being a range of contiguous (8M) blocks. I […]
Andy Colvin has the lowdown on the Oracle response and fixes for the bash shellshock vulnerability.
However, when I last looked it seemed Oracle had not discussed anything regarding the IB switches being vulnerable.
The IB switches have bash running on them and Oracle have verified the IB switches are indeed vulnerable.
[root@dm01dbadm01 ~]# ssh 10.200.131.22
Last login: Tue Sep 30 22:46:41 2014 from dm01dbadm01.e-dba.com
There has recently been a lot of news about the exploit revealed in the bash shell. While the fix is very quick to implement, there are a couple of tricks that are required to install this update on an Exadata environment. According to Oracle support note #1405320.1, Exadata storage server versions 11.2.3.x.x and 12.1.1.x.x are susceptible to the exploit. On a typical Oracle Enterprise Linux, a simple (more...)
This is based on the presentation Juan Loaiza gave regarding What’s new with Exadata. While a large part of the presentation focussed on what was already available, there are quite a few interesting new features that are coming down the road.
First of was a brief mention of the hardware. I’m less excited about this. The X4 has plenty of the hardware that you could want: CPU, memory and flash. You’d expect some or all (more...)
Enkitec’s Sizing and Provisioning (eSP) is a new internal tool designed and developed with Oracle Engineered Systems in mind. Thanks to the experience and insights from Randy Johnson, Karl Arao and Frits Hoogland, what began as a pet project for some of us, over time became an actual robust APEX/PLSQL application, developed by Christoph Ruepprich and myself, and ready to debut at Oracle Open World 2014.
This posting is about eSP, what it does, and (more...)
Today while working on ASM diskgroup i noticed Negative value for USABLE_FILE_MB. I was little surprised as it has been pretty long that i worked on ASM. So i started looking around for blogs and mos docs and found few really nice one around. A negative value for USABLE_FILE_MB means that you do not have [&hellip
Despite the title, this is actually a technical post about Oracle, disk I/O and Exadata & Oracle In-Memory Database Option performance. Read on :)
If a car dealer tells you that this fancy new car on display goes 10 times (or 100 or 1000) faster than any of your previous ones, then either the salesman is lying or this new car is doing something radically different from all the old ones. You don’t just get orders of magnitude (more...)
In Oracle Database 12c we can find many new and shiny things… So many that we can miss the little good things really easy. I think that this one, is one of them. Previously I made a post “All About HCC“, describing how HCC is working and some of the issues that we can hit […]
(the details are investigated and specific to Oracle’s database implementation on Linux x86_64)
Exadata IO: This event is not used with Exadata storage, ‘cell single block physical read’ is used instead.
Despite p3 listing the number of blocks, I haven’t seen a db file sequential read event that read more than one block ever. Of course this could change in a newer release.
One of the important things (more...)