Pythian Group

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.

Roppert Kalmar 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 . . .

Happy New Year to all our readers! Welcome to 2010 and the 174^th edition of Log Buffer, the weekly review of database blogs.

MySQL

The MySQL ’sphere since the holidays has been thick with posts on the matter of Oracle’s purchase of Sun, and thereby of MySQL. And in particular, there’s been a lot of talk about MySQL founder Monty Widenius’s response. I call all of this the . . . 

Monty My-Thon

On the 28^th of December, Monty framed the issue thus: Help keep the Internet free.

Singer Wang of Pythian, in reply, offers his perspective on GPL/ASL/BSD License Misconceptions and MySQL.

On Poo-tee-weet, Lukas Kahwe Smith is heard to say, Come on Monty . . .  “What on earth is Monty . . . thinking? How can you spin around 180 and expect to come of believable? How can suddenly the GPL be the wrong choice? How can suddenly OSS depend on proprietary sales?”

On the WireLust blog, Terrence Curran writes, Monty Widenius is trying to regain control of MySQL and why this is bad for OSS.

Kristian Nielsen shares some Oracle speculations, stating, “I think it is basically a matter of obtaining control over MySQL.”

Antony Curtis throws in his two cents: “The topic of today is [Monty's] ‘Save MySQL’ campaign and how I believe it is unnecessary.  . . .  In fact, I believe that it could be harmful.”

Read the rest of this entry . . .

Nicklas Westerlund has published the 173^rd edition of Log Buffer, the weekly review of database blogs, on SELECT mysqlgenie FROM lamp;.

Log Buffer will be off next week for the holidays, and back early in 2010 to begin another year of presenting the best of database blogs. Please get in touch with the Log Buffer coordinator if you’d like to publish an edition of your own.

Happy Holidays to everyone! Here is Log Buffer #173.

One week and a whole lot of snow later, it is time for the 173^rd edition of Log Buffer, the weekly review of database blogs. MySQL goes first this week.

MySQL

On the MySQL Performance Blog, Peter Zaitsev and his readers discuss the question, how many partitions can you have? In Peter’s opinion, “ . . . be careful with number of partitions you use. Creating unused partitions for future use may cost you.”

Also, Peter’s colleague Aleksandr Kuzminsky announces the release of xtrabackup-1.0, an “open source online (non-blockable) backup solution for InnoDB and XtraDB engines.”

On SELECT mysqlgenie FROM lamp; Nicklas Westerlund published the first part of a series on IO benchmarking for MySQL, showing the results of his tests with sysbench.

Nick will also be tackling next’s week’s Log Buffer.

Harrison Fisk’s MySQL Thoughts this week included this item about an Ext4 with MySQL binary logs oddity. “ . . . we were able to pin it down to ext4 and how it delays data writes for a very long time (30 minutes).”

As long as we’re in /var, here’s Eric Bergen, attempting to unwind the tangled web of pid file creation, which he started doing having discovered a pid file creation race condition in mysqld_safe.

Read the rest of this entry . . .

Hello, and welcome to the 171^st edition of Log Buffer, the weekly review of database blogs. Let’s get it going this week with . . . 

Oracle

Uwe Hesse, the Oracle Instructor look at result cache, another brilliant 11g new feature. He says, “There are many amazing New Features in the 11g version, one of them is the possibility to cache the result sets of statements, that access large tables but return relatively few rows. Think of it like automagically created materialized views inside the SGA.” Commenters contribute some thoughts on problems with result cache and latch contention.

Christian Antognini is, as always, Striving for Optimal Performance. He has a worthwhile post on instance caging, “ . . . nother small but useful feature of Oracle Database 11g Release 2. Thanks to it the database resource manager is able, for the first time, to limit the number of CPUs that can be used by a given instance.”

Meanwhile on The Dutch Prutser’s Blog, Harald van Breederode has a book review: Oracle Data Guard 11g Handbook. “I rate this book with 6 out of 5 stars.”

Martin Widlake examines the business of dealing with bind issues, having been shown at UKOUG the fourth solution to the problem of mixing bind variables and histograms.

And here is his Tuesday report on UKOUG so far (as of Tuesday).

Jason Arneil was also there in Birmingham, England. Here is his review of UKOUG 2009 – Wednesday.

Read the rest of this entry . . .

It is with heavy heart (and snuffy nose and throbbing head) that I regret to inform you: there will be no Log Buffer today. Your LB coordinator has some of that flu that’s so popular these days, and he can’t blow away blog congestion when he’s so busy with his own.

We’ll get through this together, LB readers! Log Buffer will return next Friday. Till then!

This is the 170^th edition of Log Buffer, the weekly review of database blogs. Welcome. Let’s kick off this week with a double-helping of . . . 

SQL Server

There are lots of good technical posts this week. The SSIS Junkie has some observations and a straw poll on sort transform arbitration. He writes, “This post was prompted by a thread on the MSDN SSIS forum today where the poster was asking how he could replicate the behaviour of SSIS’s Sort transform using T-SQL, specifically he wanted to know how the Sort transform chooses what data to pass through when the ‘Remove Duplicates’ option is checked.”

Another poll, courtesy of Tibor Karaszi: do you perform log backup for the model database?

Eric Johnson has a lesson in looping through rows in a table in SSIS 2008, which begins, “When writing code against a SQL Server, as we usually are doing in SSIS Packages, you often need to iterate over all the rows in a table. This can be done using an SSIS Foreach Loop Container, but the how is not obvious.”

Simple-Talk’s Tony Davis wonders, Do Scalar UDFs give SQL Server a Bad Name? “Many developers seem to regard SQL Server as if it were a science-fiction alien planet where unsuspecting crew-members in blue jumpers occasionally die horribly; everything is suddenly unsafe, and potentially malicious: nothing really works properly and so any serious code should be kept well away from it. Is this developer ignorance, or is their fear justified?”

From Merrill Aldrich comes a trick question — part quattro. Spoiler: TPH is an evil trap. As a commenter says: “Very interesting, I’ve never heard this vehement an argument against TPH before.”

Read the rest of this entry . . .

The 169^th edition of Log Buffer, the weekly review of database blogs, has been published on Pakistan’s First Oracle Blog by Fahd Mirza.

This is the first Log Buffer published outside Pythian in quite a while, and we’d love to have more. Log Buffer has a regular readership, and so makes a great way to present yourself and your blog to the DBA community at large. To get started, just send an email to the Log Buffer coordinator.

And now, here is Log Buffer #169.