What is RequireJS and why is it important?
Still tweaking my Python based Oracle database performance tuning graphs.
I kind of like this new version of my “sigscpuio” graph:
The earlier version plotted IO, CPU, and Elapsed time summed over a group of force matching signatures. It showed the components of the time spent by the SQL statements represented by those signatures. But the IO and CPU lines overlapped and you really could not tell how the elapsed time related to IO and (more...)
When a query contains a regular or inline view, there are 3 basic strategies for the optimizer to choose from:
1) merge the view (no “VIEW” operation in the plan)
2) instantiate the view as the whole and join it to the rest of the query (the plan shows a VIEW “operation”)
3) push join predicates inside the view (the plan shows “VIEW PUSHED PREDICATE”).
The last strategy in that list is similar to a (more...)
In my previous post I showed an example of how a query’s performance can be improved using the waste minimization technique. My focus was primarily on identifying and enforcing the correct plan, but I received some questions regarding the root cause of the problem: why the optimizer came up with a wrong join order? It’s a very interesting question, and it deserves a separate post so that it could be explored in detail.
Let’s take (more...)
I made a new graph in my PythonDBAGraphs program. Here is an example with real data but the database name blanked out:
My graphs are all sized for 1920 x 1080 monitors so I can see all the detail in the lines using my entire screen. The idea for this graph is to show how the performance of the queries that matter to the users changes as we add more load and data to this (more...)
I was attempting to install an OEM management server on a new host in the lab using runInstaller. Of course the installer is an X-windows app so I need to configure port forwarding to get the display back to MacBook.
I added the new host and its bastion to my ~/.ssh/config file to set up port forwarding:
Host newlaboms. (more...)
In Part 1 we saw that the SQL function COLLECT with the DISTINCT option is not natively supported in PL/SQL, and saw two workarounds – using dynamic SQL and using the SET function.
In Part 2 we saw that the SET function can operate on Nested Table but not on Varray.
In this post we’ll see two more workarounds.
We can first remove the duplicates in an inline view, and then use the (more...)
A few weeks ago, I received a request to review an AWR report for a database suffering from instance-level performance issues. Here are the the key parts of that report (with some masking):
WORKLOAD REPOSITORY report for
DB Name DB Id Instance Inst Num Release RAC Host
------------ ----------- ------------ -------- ----------- --- ------------
XXXX XXXXX XXXXX 1 10.2.0.5.0 NO XXXX
Snap Id Snap Time Sessions Curs/Sess
--------- ------------------- -------- ---------
More news coming, but for now, we (family and I) are moving to Seattle! We will be giving up our gorgeous rental house in San Francisco thus it will be available to the next lucky family.
Elegant mediterranean style family home on a quiet tree lined street in a sweet residential neighborhood just minutes from downtown and the Peninsula.
Perfect location for commuting to Peninsula on 280 or downtown SF (more...)
You can specify a connection string for database targets in two ways: fill in the blanks and let OEM create the connection string (my preference) or paste a Preferred Connect String on the bottom of the page.
Our default setting in our shop is to use multi-threaded servers. On the rare occasion when we need to change if, we paste the connect string from tnsnames.ora in place and add the SERVER=DEDICATED parameter.
Some things to (more...)
In a recent release that I’ve been working on, we had to drop and recreate some of the unique/primary key constraints (due to columns being added into the constraint) on some of our tables.
Prior to working in this team, I had only ever come across explicitly creating the indexes for a table, similar to:
create table test_explicit_index (col1 number,
create unique index col1_exp_pk on test_explicit_index (col1);
We can see the (more...)
Those of you who know me will know that I’m working at Cedar and we’re moving from PeopleSoft to the Oracle Cloud. I won’t talk about the company’s journey, but more how I’ve found the transition personally.
In brief, there’s a lot to learn.
Data Model knowledge
In the PeopleSoft world, once you know the table structures you could work significantly faster. Whether you were writing an SQR, an App Engine, an XMLP report, a (more...)
Just realized that I wrote a follow-up to Part 2 2 years ago and never posted it! So here’s the stripped-out key facts to round off auditing control a bit more:
Deleting O/S audit files is, like, totally necessary. In Oracle 12C (12.1), they are created by default as AUDIT_SYS_OPERATIONS defaults to TRUE now, so you are going to be filling up your AUDIT_FILE_DEST whether you realized it or not.
[NOTE: In theory, this (more...)
Oracle cost-based optimizer (CBO) is great, but sometimes it’s making wrong choices even when correct inputs are fed to it. In such cases, you need a tool to override CBOs choices, and one of the most popular tools is optimizer hints. The main reason they’re so popular is that they allow “quick-and-dirty” kind of fixes for performance issues (provided that query text can be altered). Other ways may be more reliable, but generally require more (more...)
We are moving a production database from 10.2 Oracle on HP-UX 64 bit Itanium to 11.2 Oracle on Linux on 64 bit Intel x86. So, we are upgrading the database software from 10.2 to 11.2. We are also changing endianness from Itanium’s byte order to that of Intel’s x86-64 processors. Also, my tests have shown that the new processors are about twice as fast as the older Itanium CPUs.
Two SQL (more...)
In today’s world, where everything is at the tip of your fingers, why are your enterprise systems glued to your office desk? Imagine if you could access and operate your Oracle Forms/EBS systems from any location. What if your Oracle Forms system was so agile, so easy to adapt, that any business function you do in Oracle Forms could be included in a mobile application? What would you include in your mobile (more...)
The developers complained that their test database was so much slower than production that they could not use it to really test whether their batch processes would run fast enough when migrated to production. They did not give me any particular queries to check. Instead they said that the system was generally too slow. So, I went through a process to find SQL statements that they had run in test and that normally run in production (more...)
Masking with Delphix (where duplicate blocks are shared making a new copy almost free storage wise and almost instantaneous) has 4 big advantages
- Instant data, no copying
- Ease of Use
- Consistent across data centers and databases vendors
Virtual Data Masking
Delphix masking and virtualization is the most advanced solution in the market place, because Delphix doesn’t provision data. Instead of provisioning data, Delphix sets up pointers back to existing data for a new clone. When that (more...)
It’s been forever since I last shared any of my performance troubleshooting experiences at work. This week, I got a case that I think is worth publishing, and I decided to write about it in my blog. So, here we go…
A few days ago, I received a complaint about unstable performance of one of frequently running SQL reports on a 11gR2 database. Most of the time it completed within a couple of minutes, however, on (more...)
This post comes from Fishbowl’s president, Tim Gruidl. One of Tim’s biggest passions is technology innovation, and not only does he encourage others to innovate, he participates and helps drive this where he can. Tim likes to say “we innovate to help customers dominate”. Tim summarizes Fishbowl’s Hackathon event, held last Friday and Saturday at Fishbowl Solutions, in the post below.
What an event! I want to start by thanking Andy Weaver and John Sim (Oracle (more...)