Pythian Group

Hello folks, it’s great to be back from hiatus. This is the 183rd edition of Log Buffer (arguably the best edition of Log Buffer yet!), the weekly review of database blogs.

The last time I wrote this was just under 2 years ago!!! WoW. Things have changed. Sun bought MySQL, Oracle bought Sun. Those were bombshell deals. At least you can rest assured that some things can be constant. I still eat my daily serving of broccoli (among other healthful “things”). I urge you all to go the fridge and grab some veggies prior to sitting down for this week’s… ahem… digest.

Starting with Oracle, Pythian’s own Alex Fatkulin illustrates a bug (?…likely) that could lead to logically corrupted data. Doug Burns provides an update on his Hotsos 2010 trip with some serious thumbs-up action pointing in Tanel Poder’s direction and his affinity toward SQL*Plus.

Over at Mark Rittman’s Oracle Weblog, Venkatakrishnan J talks about Oracle Warehouse Builder 11gR2 – Importing Essbase Cubes using ODI Knowledge Modules – Part 1. This should drive the MySQL folks bonkers (in a good way) since he points to an example by David Allen to import MySQL Metadata over and vice versa.

Oracle Virtualization Blog’s Adam Hawley let everyone know about a Best Practices around Oracle VM with RAC RAC SIG webcast. It was on March 18th, but it was recorded and should be available online. I’m interested in this stuff so I included it here. I hope you can enjoy it too.

I had the honour to recently provide a training session at a customer site on tuning methods and tools. A key topic of the discussion was related to Oracle statistics and the CBO. It was timely that the Oracle Scratchpad’s Jonathan Lewis posted a series created by Doug Burns all about stats. Nice.

Has anyone ever told you (or maybe you deduced it on your own) that leaving out where clauses is a bad thing. Well, leave it to Charles Hooper on his Oracle Notes to prove to us that sometimes, they are actually more efficient for solving certain types of problems. In another excellent post titled Physical Reads are Very Fast, Why is this SQL Statement Slow Charles also dives into why a slow query is “actually” slow. There’s an interesting discussion taking place. More performance tuning goodness was posted by Joel Goodman discussing some interesting behaviour with Oracle Index Leaf Blocks contention. Tell RAC to Leave Your Leaves Alone! Kerry Osborne illustrates the use of an interesting hidden parameter (_high_priority_processes) to resolve “log file sync” issues.

Over on the other side of the fence in the MySQL world, Jay Pipes @ Join-Fu gives us some background on the MySQL Transaction Log. Vadim Tkachenko with the MySQL Performance Blog has a number of posts on Percona 9.1 as well as a list of related sessions at the 2010 MySQL conference. Check it out.

On a more somber note (and by somber I mean legal, we all hate legalese don’t we?), Giuseppe Maxia over at The Data Charmer discusses Protocol, the GPL, and how Bazaar can help. He also has some good takeaways from the Linux MySQL distros meeting in Brussels. Baron Schwartz at xaprb has a new tool he’d like the MySQL folks to take for a spin. Try mk-query-advisor, a new Maatkit tool. It uses heuristics to find problems in SQL. Please use it and give feedback!

Are you interested in MySQL Clustering? I am. Andew Morgan has a new post introducing a tutorial to Build MySQL Cluster 7.1 from source – including MySQL Cluster Connector for Java. With Alex Fatkulin maybe running into an as yet possibly, sort of , kinda non-discovered bug, it’s only fair we also get some vision into the dark side on the MySQL front. Shlomi Noach states But I DO want MySQL to say “ERROR”!.

Brian Aker invites readers to participate at this year’s O’Reilly MySQL User’s Conference where they will be doing their first ever Ignite talk series.

Lastly, Stewart Smith has a very good set of posts illustrating Stored Procedures/Functions for Drizzle. Check this out (from Stewart’s post).

drizzle> select libtcc("#include <string.h>\n#include <stdlib.h>\nint foo(char* s) { char *a= 0x199c610; strcpy(s, a); return strlen(s); }") as result;

+--------------+
| result       |
+--------------+
| Hello World! |
+--------------+
1 row in set (0.01 sec)

I dare you.

On to SQL Server….

Scary DBA SQL MVP Grant Fritchey discusses Undocumented Virtual Column: %%lockres% and also recaps the SNESSUG March Meeting.

Jamie Thomson gives keyboard junkies some tips to Kill your temp tables using keyboard shortcuts : SSMS. Anyone interested in distributed queries should read Buck Woody’s Using linked servers, OPENROWSET and OPENQUERY.

Finally, Aaron Bertrand says with conviction “Yes, you can benefit from both data and backup compression”.

Having now exhausted my supply of munchies, it is time for me to retire. I bid you all a fantastic week. Keep your data safe, folks.

Shakir

If you do not know what International Women’s Day is: http://www.internationalwomensday.com/

Start planning your blog posts for Ada Lovelace day now (March 24th, http://findingada.com/ Ada Lovelace Day is an international day of blogging (videologging, podcasting, comic drawing etc.!) to draw attention to the achievements of women in technology and science.)

To that end, I would like to point out all the women currently in science and tech fields that I admire and think are doing great things. I think it would be great if everyone, male or female, made a list like this:
Read the rest of this entry . . .

The 181^st edition of Log Buffer has been published by Gary Myers on his Sydney Oracle Lab.

Having recently moved his blog, Gary approached the Log Buffer coordinator to volunteer for an edition because he knows that, with LB being a popular and established destination in the database blogoshphere, it would help him broadcast his new blog and welcome readers to it. You can do it too–simply send an email to the Log Buffer coordinator.

Here’s Gary’s Log Buffer #181.

Hello and welcome to Log Buffer #180. Time’s a-wastin’, so let’s go!

Oracle

There was so much Oracle stuff this week that I’ve decided to cram a little more of it into Log Buffer by providing a little less context than usual.

Jonathan Lewis shares an explication of aliases: “I was asked the following question recently: ‘Does the use of table aliases affect performance?’ To which the best answer is probably ‘Yes, though in general you probably won’t notice the difference and there are reasons more imporant [sic] than performance for using table aliases.’”

Doug Burns continues his most recent series: Statistics on Partitioned Tables – Part 2, and Statistics on Partitioned Tables – Part 3.

Charles Schultz demonstrates how VPD + bad ANYDATA practices can really bite: “The point of my blog was that using CAST can really screw up your data. Oracle Support is filing a bug on this behavior, as it looks like an overflow problem.”

Pythian’s Gleb Otochkin begins a series on Oracle GoldenGate installation.

Guy Harrison provides a thorough introduction and recommendations on memory management for Oracle databases on VMWare ESX.

Robert Vollman returns to blogging and offers his 10-point plan on improving your SQL queries.

Jared Still sheds some light on a cool but unknown RMAN feature. Read the rest of this entry . . .

You have found the 179^th edition of Log Buffer, the weekly review of database blogs. Welcome. Enjoy your stay. We begin with . . . 

SQL Server

Merrill Alrich gets going with a fresh juxtaposition–his thoughts on motorcycles and Access. “Many DBAs,” he writes, “have been called in to rescue people, or teams, or projects who have mission critical Access applications gone horribly wrong. It’s very unpleasant, especially the typical discussion we have to have with the Access afficionado . . . ”

Brent Ozar is in on this discussion too. Here he gives his top 10 reasons why access still doesn’t rock.

Brent’s blog also has an interview with Joe Sack, “ . . . public face for the SQL MCM program.”

Aaron Bertrand has a couple new items in his Bad Habits to Kick series: inconsistent table aliasing and blind SQL Server installs.

The Rambling DBA Jonathan Kehayias, advises, pay attention to maintenance cleanup job configuration, specifically with regard to backup files.

Jeremiah Peschka shows how a simple refactoring of functions in the WHERE clause can turn a performance disaster into success. Read the rest of this entry . . .

Gerry Narvaja has published the 178^th edition of Log Buffer, the weekly review of database blogs.

LB is always looking for contributors, so if you’d like to publish an edition of your own, drop a line to the Log Buffer coordinator. It’s an excellent way to put your stamp on the database blogosphere.

Here is Gerry Narvaja’s Log Buffer #178.

Welcome, everyone, to the 177^th edition of Log Buffer, the weekly review of database blogs. It was another week heavy with technical posts, so let’s waste no time, and get it all started with . . . 

PostgreSQL

David Fetter shares his recipe for adding only new rows: “Let’s say you have a table and a data set, and would like to add only those rows in your data set that aren’t already in the table. There are hard ways, but here’s an easy one.”

Simon Riggs, the Database Explorer, offers his thoughts on parallel query in Postgres: “I’m disappointed we’ve not made much progress with parallel operations and partitioning in core Postgres in last few releases. Recent Greenplum results show we have much work to do in improving things.”

David Christensen shares a PostgreSQL tip: using pg_dump to extract a single function.

Robert Gravsjö shares a screenshot of the new Sun Oracle PostgreSQL. That doesn’t even sound right, does it?

Read the rest of this entry . . .

This is the 176^th edition of Log Buffer, the weekly review of database blogs.

There were heaps of mostly technical posts this week. I think bloggers are tired of kicking around the ins-and-outs of Sun and Oracle, and wanted to talk about what really matters. So let’s start with . . . 

Oracle

Harald van Breederode shows how to setup a private DNS for your virtual cluster.

Pythian’s Alex Fatkulin discusses Oracle GoldenGate Extract Internals.

From Charles Hooper comes this investigation: Simple Query Generates Complex Execution Plan, the Mysterious 4063.88 Second Single Block Read Wait.

Coskan Gundogar was also in a deductive frame of mind. Here is his Working with statspack-part-1a-Diagnosis, featuring both a challenge and purty pictures (pastels!).

Here is Jonah H. Harris with an introduction to the NEXTGRES Gateway, a MySQL Emulator for Oracle. Jonah writes: “So, a few people have asked me what NEXTGRES Gateway is. My short answer, the ultimate database compatibility server.  . . . I’ve been working on this personal project non-stop for the last 8 months and am really excited about it.”

Read the rest of this entry . . .

Welcome to the 175^th edition of Log Buffer, the weekly review of database blogs.

Oracle

Let’s begin with remoteDBAexperts blog, and Chris Foot’s prediction of the future of database tuning and database administration. It will be, “ . . . administrators interpreting and implementing the recommendations generated by the intelligent advisors and ADDM.  . . .  I also think that Oracle will eventually become self-tuning.”

Here in the present, DBAs (Oracle and otherwise) are still Striving for Optimal Performance as Christian Antognini is. Here’s his item on join elimination, which he introduces thus: “In some specific situations the query optimizer is able to completely avoid executing a join even if a SQL statement explicitly calls for it. Two are the cases currently covered by this optimization technique, which is called join elimination.”

Jeff Hunter of the So What Co-operative was at the optimizer too, and found an interesting optimizer result, and pursued it into Interesting Optimizer Result, Part II. “If the query included the package call in the WHERE clause, the query finished in over an hour. If the package call was not in the WHERE clause, the query finished in 5 minutes (but did not return the correct results).  . . .  Confident in my fondness for inline views, I ran the query fully expecting to get the results back in a few minutes. Except the query went on, and on, and on for a full 15 minutes before I killed it.”

Kellyn Pedersen discusses what to do when PGA size is not enough. Read the rest of this entry . . .

Most people start with free databases and eventually get to know the enterprise products. I started the other way around.

After being trapped for eight years in the Oracle world, I felt like exploring another database platform. For some reason I can’t get myself to fiddle around with MySQL. There’s nothing rational about this–no benchmarks, reviews, or co-worker horror stories. I feel it’s just not my type.

So when looking for free database, I reached out for PostgreSQL, again for no objective reason–only the gut feeling that this could be what I’m looking for.

Read the rest of this entry . . .