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.

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.

Richard Foote knocks holes in another myth: “One of the great myths in Oracle is that bitmap indexes are only suitable and should only be used with columns that have so-called low cardinality (few distinct) values.”

Alexander Kornbrust shares a link to a really good whitepaper about “Hacking Oracle from the Web” by Sumit Siddarth.

Eddie Awad shares a link to a SQL injection prevention cheat sheet.

Charles Hooper answers the question, What is the meaning of the %CPU column in an explain plan?.

Meanwhile, Harald van Breederode does the same for this one: Why does the size of my ORACLE_HOME increase?

SQL Server

Thomas LaRock gives an recap of MS’s 2010 MVP Summit. Quotable take-away: “If I had to compare SQL 2008 R2 to SQL Server 4.0, I would say the difference is the same as comparing an F1 race car to a Chevy Vega.”

Half a world away, there is the SQLSocial Event – London March 16th, as advertised by Simon Sabin.

Simon also shares a script to get indexes and their included columns, beginning, “I get increasingly frustrated with the lack of visibility of included columns in management studio and from the system stored procedures sp_… This is a query that returns all indexes and there key and include columns[.]”

Andy Leonard throws us another nourishing SSIS snack: conditional split outputs.

Here’s Rob Farley with a book review of an oldie but a goodie: Inside SQL 2005 Query Tuning and Optimization, by Kalen Delaney et al. “If you spend any time tuning SQL Server databases, then this book will feel much thicker than it really is, and you’ll be finding useful information on just about every page.”

Thomas LaRock, meanwhile, writes that SQL Server 2008 Query Performance Tuning Distilled is
a good way to start your day. “Each morning, while I wait for my desktop to boot, I pick up their book, turn to any page, and just start reading.”

MySQL

Sticking with the theme a little longer, here is Baron Schwartz with a review of Understanding MySQL Internals by Sasha Pachev. “I should have read this book a long time ago, and it’s my loss that I didn’t.  . . .  Overall, this book is easily a high 4 stars on a scale of 5, and again, anyone seriously using MySQL should have it.”

Baron also shares a link to Oracle guy Cary Millsap’s Thinking Clearly about Performance paper.

Brian “Krow” Aker starts an extensive conversation with his post, Protocols, The GPL, Influences from MySQL. His thesis, “MySQL was the company that had the most influence on how companies and investors viewed the GPL.”

Paul Vallée of Pythian responds with his ideas on product management, effective developers, and the future of MySQL. “ . . . the future of MySQL, Drizzle, Monty Program, the Percona fork, etc.” to be more precise.

Colin Charles provides news of what’s been happening recently in MariaDB #1.

Mohammad Lahlouh wonders, can I use latin1 to store utf8 data? and gets several answers from his readers.

He might have asked Ronald Bradford, who knows this stuff. Here is his post on migrating MySQL latin1 to utf8 – character set options.

Pursuing a similar matter (collations), Roland Bouman opines, the best stored routine is the one you don’t write.

PostgreSQL

Baron Schwartz again! He announces, mk-query-digest now supports Postgres logs.

David Fetter says, part(ition)ing is such sweet sorrow. “There are excellent references on partitioning tables that depend on one table, but what happens when you need to partition the referenced table? Let’s find out!”

Bruce Momjian is here with news on the Python driver confusion.

Jon Jensen of End Point’s Blog posts a HOWTO on PostgreSQL EC2/EBS/RAID 0 snapshot backup.

NoSQL, Etc.

Chen Shapira has been at the compass and protractor, mapping the NoSQL space and returns from terra incognita unscathed.

Ronald Bradford has been getting started with Cassandra, one of the outposts on Chen’s map, and shares his steps.

Arnie Rowland says, “Mark your calendar! Portland SQLSaturday/CodeCamp/Barcamp 2010 is scheduled for May 22, 2010, at the University of Portland campus.  . . .  Portland SQLSaturday is encouraging presentations related to interoperability of any of the SQL platforms, including T-SQL (SQL Server), PostgreSQL, MySQL, and PL-SQL. Abstracts for Platform specific sessions are also encouraged.”

Okay, that is all for this edition. You guys are running me ragged! Fortunately, Gary Myers picks it up next week on his Sydney Oracle Lab. Till then!

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. He says, “Putting functions in the where clause of a SQL Statement can cause performance problems. If you aren’t careful, these problems can add up and bring a powerful production system to its knees.  . . .  [If] we move the function from the table to the variable . . . [this] is going to be orders of magnitude faster . . . ”

John Paul Cook introduces his favorite free tool, SQL Heartbeat. “There are many great scripts available,” writes John, “for monitoring SQL Server. But admit it, don’t you miss animation and color? I’ve been using SQL Heartbeat for about two weeks and I really appreciate the animation and color. These features make the output highly effective and easy to grasp.”

MySQL

Mark Callaghan gets our MySQL stuff started. “What is the future for MyISAM?” He asks. “MySQL has invested a lot in storage engines over the past few years (Falcon, Maria) and it isn’t clear that anything will come from those efforts. A lot of effort has been put into InnoDB and much will come from that. There has not been a significant effort to improve MyISAM (other than hot backup). What could be done with it?” The post is Save MyISAM.

The ThetaJoin Blog features a review of the MySQL Administrator’s Bible. The author writes, “On the front cover of MySQL Administrator’s Bible is a sentence that reads: ‘The book you need to succeed!’ I must say, I do agree.”

Over on the MySQL Performance Blog, Vadim compares READ-COMMITED vs REPETABLE-READ in tpcc-like load. “[The] question, what is better isolation level is poping up again and again. Recently it was discussed in InnoDB : Any real performance improvement when using READ COMMITED isolation level ? and in Repeatable read versus read committed for InnoDB . Serge in his post explains why READ COMMITED is better for TPCC load, so why don’t we take tpcc-mysql bencmark and check on results.”

Giuseppe Maxia, the Data Charmer, reports on the Linux MySQL distros meeting in Brussels. He says, “When I saw Shlomi’s post on why not to use apt-get or yum for MySQL, I thought immediately that his conclusions are quite reasonable. What you get from the Linux distributions is not the same thing that you find in the official MySQL downloads page.  . . .  We at the MySQL team have organized a meeting with the Linux distributions with the intent of finding out which differences and problems we may have with each other, and to solve them by improving communication.”

Speaking of distros, here is Falko’s How To Set Up MySQL Database Replication With SSL Encryption On CentOS 5.4 on HowtoForge.

PostgreSQL

Meanwhile, in the PG ’sphere, Jeremiah Peschka walks through installing PostgreSQL on Mac OS X, “ . . . a pretty simple process, but one that I thought I would document because I ran into a few gotchas along the way.”

Leo Hsu and Regina Obe introduce the subject of regular expressions in PostgreSQL, on the Postgres OnLine Journal. “Every programmer,” they say, “should embrace and use regular expressions (INCLUDING Database programmers). There are many places where regular expressions can be used to reduce a 20 line piece of code into a 1 liner. Why write 20 lines of code when you can write 1.”

Marc Balmer’s PostgreSQL blog looks into using PostgreSQL to decouple applications, or, OO meets SQL (Part I): “What works at the object level in an object oriented programming language can be applied to distributed PostgreSQL applications as well, allowing for proper decoupling of applications or application parts. The tools needed for this are PostgreSQL’s trigger procedures and the asynchronous notification mechanism. In this first installment of a small series of blog entries, I will talk about the basics needed to implement a distributed decoupled software solution.”

Oracle

The Oracle world is full of sturm und drang this week. Accusations, recriminations, and enigmas–of the technical kind–abound.

Kerry Osborne asserts that autotrace lies too, following up an older post of his on explain plan’s untruths: “Autotrace is another commonly used tool that suffers from the same basic character flaw (i.e. it lies too). The reason is simple. It uses the Explain Plan command under the covers.”

Richard Foote, for his part, looks for answers to this puzzler: how does an execution plan suddenly change when the statistics (and everything else) remains the same?

Charles Hooper, meanwhile, wonders aloud, V$FILESTAT is Wrong?

According to James Morle, The Oracle Wait Interface Is Useless (sometimes), the third in a series. “In this part I will finally get to the point, and talk about some alternative techniques for determining the reasons for poor performance for our example user session.” Pythian’s Mark Brinsmead says this is “hyper-cool.”

On The Blog from the DBA Classroom, Joel Goodman shows how to tell RAC to leave your leaves alone. “One use of sequences about which most DBAs and developers are aware is that of generating primary keys for a table and naturally the key data for the underlying index.  . . .  But the choice of sequence parameters can have an effect on performance when using high volume insert applications in a RAC database environment. The problem is one of Index Leaf Block contention . . . ”

Doug Burns is here with the first part of a series on statistics on partitioned tables, which he introduces thus: “We’ve encountered a few problems at work recently and I decided it would be an idea to put together a series of posts covering the basics of what can become quite an involved topic because it’s not difficult to find yourself going round in circles reading the documentation, Oracle Support Notes, blog posts, forum threads and the rest until you don’t know whether you’re coming or going!”

Martin Widlake has a thoughtful post on the DBA and his or her job, called, Making Things Better Makes Things Worse. He says, “I’m encountering a phenomenon that I have talked about with Dennis Adams a couple of times. It probably has a proper term, but basically it is the odd situation that when you make things better, you get more complaints.”

That’s all for this edition. See you for LB#180!

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.

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?

Oracle

Let’s begin with Chen Shapira, since she is so excited about the NoCOUG Winter Conference, and here gives a quick rundown of what attendees can expect to see.

Contrariwise (or not), Iggy Fernandez offers five reasons not to attend a NoCOUG conference in 2010. “Most Oracle professionals will benefit a lot from attending a NoCOUG conference in 2010. However, the following categories will not benefit much:  . . .  Those Oracle professionals who believe that Oracle’s goal in buying Sun is to replace Oracle Database with MySQL. This is probably a very small group . . . ”

Uwe Hesse, the Oracle Instructor and his readers share a discussion on sharing READ ONLY Tablespaces between databases. Uwe says, “ . . . the question was raised, whether it is possible to use the same READ ONLY Tablespace in multiple Databases. At first glance, I thought that this should of course be possible, though the answers where somewhat discouraging. So I have done a quick test to prove it . . . ”

Krishna Manoharan of Performance Engineering and Capacity Planning steps up with an item on understanding CPU time as an Oracle Wait event. Krishna pursues the question, “[What] if the stats from the system show that CPU Utilization (% Util and Run queue) are well within thresholds and show plenty of available capacity, but Oracle continues to report CPU time as a Top 5 wait event?”

Charles Hooper grapples the question, Which Plan is Better? Charles writes, “A recent post appeared in the OTN forums that indirectly asked the question: which execution plan is better?  . . .  If you are attempting to conclude which plan is faster/better based on the estimates in [a] first plan and an altered plan with a hinted cardinality estimate, you might be setting yourself up for failure.”

“Seems like all I ever write about these days is SQL Profiles,” writes Kerry Osborne. “I do other stuff, honest! It just seems like getting Oracle to do what you want when you can’t touch the code is the closest thing to ‘Magic’ that DBAs get to do.” Here’s Kerry’s post on single-hint SQL profiles, inspired by a discussion with Jonathan Lewis.

And now here is Jonathan with a post on SQL Server.  . . .  Wait a minute–what the?!

SQL Server

Ahem. And now here is Jonathan Lewis with a post on SQL Server. Yes, Jonathan Lewis, famous Oracle guy. “A few days ago,” Jonathan writes, “I did a presentation on SQL Server.  . . .  The title was ‘What the Enterprise needs in an RDBMS’ . . . and the presentation was about whether or not you could find everything you needed in SQL Server 2008, where you’d have to look in the manuals, and supplementary questions you’d have to ask.”

Buck Woody also has been, as it were, treading the boards: “I give series of classes and presentations on Data Design. I say ‘data’ design instead of ‘database’ design because we should consider more than just the database.  . . .  Here are the links I use in that presentation. Although this isn’t a comprehensive list of Data Design topics, I’ll visit this topic from time to time so you may want to bookmark this page in your favorites[.]”

Merrill Aldrich admonishes, don’t get burned by replication of SQL Server files: “ . . . if you try to use file system replication (robocopy, xcopy, repli-whatever) to maintain a DR server from your production SQL Server, you might be in for a nasty surprise.”

Buck Woody relays more nastiness in his post, Transparent Data Encryption and the Latest Data Breach: “Well, It’s happened again. Hundreds of thousands of private records were stolen from a database. This one, however, was different. No one stole any passwords, no one did any social engineering, nothing was captured in-line. No, this one was accomplished by stealing the actual hard drives themselves!”

One way to circumvent this–no hard drives! But wait–before you send them all to the kilns, Aaron Bertrand says, your laptop may be ready for SSDs, but are your SQL Servers? “I am not trying to be Debbie Downer here,” he explains,” … SSDs sound great . . .  But right now, if you are looking at expanding or upgrading your I/O under SQL Server, I’d give the vendors some time to shake off these early jitters.”

Here’s Thomas LaRock, DBA Survivor, with a Name That Caption Contest. The deal is: “The person who provides the best caption will win a copy of my book,” DBA Survivor, “and I will figure out a way to incorporate your caption into the main page.”

MySQL

On Serge’s blog appears a useful item on using UNIX_TIMESTAMP as a partitioning function for MySQL 5.1.43

Falko Timme shares How To Back Up MySQL Databases With mylvmbackup On Debian Lenny on HowtoForge.

Simon Mudd has some further thoughts on mysql upgrades.

From atop his MySQL Soapbox, Lachlan Mulcahy address the matter of a replicate-do-db gotcha, discovered lurking in the config file.

Gotcha again. Dathan Vance Pattishall says, “INNODB has some irritating gotchas that makes disk space management hard. In 2002ish INNODB, added innodb_file_per_table to get around allot of these issues, but it does not fix everything.” The post is innodb_file_per_table, shrinking table spaces and the data dictionary.

On EXPLAIN EXTENDED, Quassnoi examines some details of join on overlapping date ranges in answering the question, “Is there any way to optimize the query for overlapping ranges in MySQL if both ranges are dynamic?”

Last, The InfiniDB Team Blog announces that InfiniDB 1.0 is Now Available!

That’s all there’s room and time for. Let’s hear your favourite DB blogs from this week, and we’ll see each other again in the next one. Till then!

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.”

John Hallas lays out the use of functions in a .profile file.

MySQL

In a different part of config file land, Ronald Bradford cautions us, be sure to know your my.cnf [sections]. “The MySQL configuration file,” he writes, “e.g. /etc/my.cnf has a number of different section headings including [mysql], [mysqld], [mysqld_safe]. It is important that you ensure you put the right variables into the right section.”

Sheeri K. Cabral responds with Know your my.cnf groups, part II.

Baron Schwartz inspires a lot of conversation with his post, My wishlist for SQL: the UNTIL clause. Baron says, “I’d like an UNTIL clause, please. I’d use it sort of like LIMIT in MySQL and PostgreSQL, except that it would define when to stop returning looking for rows, instead of defining how many to return.”

Roland Bouman has gone about adding stuff to MySQL on his own, as he demonstrates in Easter Eggs for MySQL and Kettle with a MySQL stored function to calculate easter day.

Speaking of things hidden, here is a note from Andrew Morgan pointing out the location of MySQL documentation and binaries.

Marc Alff is looking forward, and offers a performance schema overview, “ . . . an introduction to the new ‘performance schema’ feature, which will be part of the upcoming MySQL 5.5 release.”

We must have at least one post on the whole Sun/Oracle thing, and I found a good one–Oracle, MySQL, the EU and Wayne Gretzky, by Mike Hogan. The keynote: “‘A good hockey player plays where the puck is. A great hockey player plays where the puck is going to be’ — Wayne Gretzky”

SQL Server

To quote Oracle blogger Kevin Closson, “little things doth crabby make.” Or as Aaron Bertrand would put it, Sometimes it’s the small things: match column names in subqueries. Aaron writes, “The behavior of column matching in subqueries is a little peculiar, to say the least. If you’ve been bitten by this behavior once, you’re unlikely to have been bitten a second time, but for some of us it just takes a while to sink in.”

Jonathan Kehayias has another puzzler: is NT AUTHORITY\SYSTEM a sysadmin in your SQL Server and why? “I was prompted to ask this question while configuring a server early today and after installing SQL Server 2008 on Windows Server 2008 R2, I noticed that despite being installed from default using a Domain Account for the Services, the Local System account was still a sysadmin in SQL Server.”

Another little thing, courtesy Roman Rehak: “One of the things that I found dissapointing in Management Studio 2008 is that in the event of a crash (and in addition to crashing in the first place), is that on a restart it doesn’t show me a dialog with a list of auto-saved files, like my SSMS 2005 did.” But, he says, your work may not be lost.

Michelle Ufford has updates on her index defrag script – beta testers are needed.

Simon Sabin shares SQLBits videos for SQLBits V.

PostgreSQL

Bruce Momjian relays an appeal for a new project slogan for Postgres, and shares the leading candidates thus far. “PostgreSQL: The ‘Open’ Open Source Database” Who can they be comparing themselves to? “PostgreSQL: Unpronounceably awesome!” That’s the one!

Bruce also enumerates what he sees as threats to Postgres.

Hubert Lubacziewski notes that he is now waiting for … 9.0: “I’ve written 29 posts about new features in 8.5. And now core team decided to name it 9.0. Great.”

And so the Database Explorer appears with a brief update on 9.0 Replication Features.

Last, Kendal Van Dyke exhorts you to use your tech skills to help Haiti. He writes, “So what do you do if you want to help?  . . .  I came across an article on cnn.com which highlighted “Crisis Camp Haiti”, a group of volunteers working to build digital maps, mobile apps, and searching through data to help relief groups in Haiti coordinates their efforts. They’ve got a website up at http://crisiscommons.org/ and you can follow them on Twitter (@crisiscamp).”

That’s all for now. See you for LB #177!

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. Kellyn says, “I’ve come to realize that most folks don’t really understand the limitations in the allocation of PGA memory to hashing and sorting. They truly believe that if they set their PGA high enough, the database will just allocate as much memory as they have in the setting towards any hash or sort process, when in truth, there is a ‘threshold’ . . . ”

Marko Sutic writes, “Before database migration to new version it is always wise to test how will applications work on this new version.  . . .  But what if you have in production very big database and your test storage is limited – then partial restore of a database comes as handy solution.”

PostgreSQL

The End Point Blog looks at the flip-side of the restore, the backup: Postgres SQL Backup Gzip Shrinkage, aka DON’T PANIC!!!, exposing a little wrinkle in pg_dump.

Leo Hsu and Regina Obe of the Postgres OnLine Journal show just why they are looking forward to PostgreSQL 8.5.

Hubert Lubacziewski is likewise waiting for 8.5 – PL/pgSQL by default being one of the reasons. “ . . . Basically from 8.5 on PL/pgSQL will be enabled by default in all databases.”

Peter Eisentraut also is excited— . . . the next PostgreSQL release will be a great one for procedural languages.”

When the time comes to do that upgrade, The End Point Blog’s post, Postgres Upgrades – Ten Problems and Solutions will prove a useful resource.

Here is David Wheeler with an SQL hack: the something-est from each entity.

Andrew Dunstan has been looking at the MySQL/Monty/Oracle controversy, and feels what he calls, MySchadenfreude. He writes, “I don’t really take great joy in the turmoil in the MySQL world, but it’s very tempting every time that Richard Stallman or Monty Widenius open their mouths on the subject not to cheer on the opposition.  . . .  And I don’t appreciate misrepresentations and FUD concerning Postgres in Monty’s latest rant.  . . .  I don’t think Oracle will do MySQL much good, and I wouldn’t trust them as far as I could kick them. But that doesn’t mean we should just embrace any bad argument against the acquisition that comes along.”

MySQL

The good news, according to Mark Hinkle of the Socialized Software blog, is that MySQL and PostgresSQL jobs are on the Rise, Oracle job postings decline, according to statistics from indeed.com.

Charity Linden of the Second Life Blog, shares a Diary of a Paranoid MySQL Upgrade, which begins, “At 6 am on January 6th, our central database was upgraded from mysql 4.1 to 5.0.  . . .  This was not our first shot at an upgrade. We first tried to upgrade way back in November of 2007, but it turned out that 5.0 was just not fast enough . . .  After two or three long, wretched days of cascading downtimes, degraded services, and intermittent data loss, we gave up and rolled back to 4.1, all thoroughly traumatized by the experience.  . . .  This is the story of our successful second attempt, and all the things we learned and checked and verified in order to make it successful.”

Masterzen’s Blog announces the launch of mysql-snmp 1.0, an SNMP monitoring for MySQL. “mysql-snmp is a mix between the excellent MySQL Cacti Templates and a Net-SNMP agent. The idea is that combining the power of the MySQL Cacti Templates and any SNMP based monitoring would unleash a powerful mysql monitoring system.”

Morgan Tocker reveals his MySQL Conference submission: workarounds. He writes, “Domas likes to do tricks with GDB. Sheeri likes symlinking log files to /dev/null when not in use. Peter likes to do what he calls a delayed join, and I like to use IN() lists.  . . .  What’s your favorite workaround? Are there any that you’ve seen people use in production that no longer work (or could be considered harmful)?”

Morgan’s colleague on the MySQL Performance Blog, Peter Zaitsev, writes, “One of the problems I have with Memcache is this cache is passive . . .  This means application using Memcache has to has to special logic to handle misses from the cache, being careful updating the cache – you may have multiple data modifications happening at the same time. Finally you have to pay with increased latency constructing the items expired from the cache, while they could have been refreshed in the background. I think all of these problems could be solved with concept of active cache.”

SQL Server

The Rambling DBA, Jonathan Kehayias tells the story of his downgrading from SQL 2008 to 2005. He says, “Every couple of weeks on one of the forums someone will ask a question about how to restore a backup from SQL 2008 to SQL 2005. The answer to the question is always, you can’t restore a backup to a lower version of SQL Server. If you need to migrate backwards it is an entirely manual process.”

Paul S. Randall challenges some misconceptions around database snapshots and transaction rollbacks with, “ . . . a quick post to clarify an article I saw . . . this morning that seemed to state that transaction rollbacks push data into database snapshots. This is absolutely not true.”

Henk Van Der Valk examines an approach to optimizing SQL in-memory table scan processing speed. He says, “How fast can you can actually read data from a table that is already loaded in memory?  . . .  People often assume that, once it’s in memory, it’s as fast as it can get and won’t get any faster? But how fast is it really?”

Here’s another question: Would you optimize SQL for less performance? So asks Linchi Shea.

Jamie Thompson, the SSIS Junkie, bemoans what he deems the SQL developer gap: “I look around at our cousins in .Net land and I see their fancy WPF code editors, extensible languages . . . fluent this-that-and-the-other etc… and I can’t help but feeling a little hard done by. (Anyone that has used Resharper for .Net will know exactly what I mean.) Am I the only SQL guy that feels like a second class citizen in the Microsoft developer ecosystem?”

Buck Woody needs your help on a like matter, the database design process. He says, ” I know how I create databases, and I’ve watched a lot of other data professionals follow their own processes for that, but I want to know how YOU do it.  . . .  I currently use DBDesignerFork  . . .  which is not a perfect tool. But Microsoft doesn’t have a good one . . . ”

That’s all for this edition of Log Buffer. As always, you’re welcome to note your own favourite DB blogs from this week in the comments.

Till next time!

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.”

All that aside, things keep rolling, and DBAs keep DBAing. Simon Mudd shared his thoughts and some suggestions on managing MySQL grants.

On someGreatTechName, Piotr Jasiulewicz shows how to get data without reading it – the power of covering indexes in MySQL.

Geert Vanderkelen, Some Abstract Type, has the coolest-looking rows ever in his post, A chessboard in MySQL: make your moves.

Peter Zaitsev of the MySQL Performance Blog lays out the principles of upgrading MySQL, “ . . . a very interesting task as you can approach it with so much different ‘depth’. For some this is 15 minutes job for others it is many month projects. Why is that?”

SQL Server

On the SQL Server side, Aaron Bertrand likewise shares his experiences upgrading 2005 => 2008, describing the steps he took in his careful crossover.

Aaron also has a quick poll: what is your favorite Management Studio tip or trick?

Dan Jones has a question too: “ . . . there are two types of DBAs: those who are myopic and those who are leaders.”what kind of DBA are you?

Simon Sabin wonders aloud, Should PASS hold the conference on the East coast?

Simon also has his latest TSQL challenge – remove duplicates from a string.

If that’s not enough T-SQL for you, Adam Machanic has issued his invitation for T-SQL Tuesday #002.

Oracle

Let’s begin with nothing. Tanel Poder wishes to remind us that NULL is not zero!, with, “an example [of] how misunderstanding NULLs may cause your application to return different results than what was intended.”

Martin Widlake has been busy decoding high_value and low_value for us. He writes, “The table DBA_TAB_COLUMNS holds the LOW_VALUE and HIGH_VALUE for columns. This information is potentially very useful to us . . .  What is not so helpful is that Oracle stores, and displays, the information in an internal raw format. Which is utterly unhelpful to us of course.”

Jonathan Lewis clarifies copy stats. “ . . . someone was having trouble,” he writes, “copying stats from one index to another using the import_index_stats and export_index_stats procedures from package dbms_stats modifying the contents of their ’stat table’ between the export and import.  . . .  Part of the problem with this approach is that you’re not really supposed to do what they were trying to do . . . ”

Guy Harrison, meanwhile, elucidates 11gR2’s IGNORE_ROW_ON_DUPKEY_INDEX hint, “ . . . [one] of the strangest new features in 11GR2 . . .  Why is this so strange? Mainly because unlike almost all other hints, this hint has a semantic effect: it changes the actual behavior – not just the optimization – of the SQL.”

Walking in the footsteps on Vasco da Gama, Luis Moreno Campos proclaims himself the first Portuguese Oracle nerd to unpack an Oracle-Sun Exadata v2. Congratulations, Luis! I think.

And we close this edition of Log Buffer with Jonathan Lewis, who on first principles, “ . . . just had to start the new year with a little humour,” courtesy of Og, Sumerian DBA.

That’s all for now. If I’ve missed you favourite DB blog from the last week, please leave a comment. See you again for LB #175.

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.

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.

Here on the Pythian Blog, Sheeri K. Cabral reports that active support for MySQL 5.0 ends soon.

Lenz Grimmer announces the call for papers for the “MySQL and Friends” developer room at FOSDEM 2010.

PostgreSQL

Dave Page, PostgreSQL hacker and core team member, brings word that PostgreSQL at FOSDEM 2010 – the call for talks has been issued. Dave also has a post clarifying the PostgreSQL release support policy.

Dan Langille, coordinator of the PGCon conference, shares bsdtalk’s interview with himself on BSDCan/PGCon 2010.

SQL Server

Linchi Shea exposes the performance impact of UNION ALL views, ANSI_PADDING, and bad query plans. Writes Linchi, “Whether or not you specify it explicitly, ANSI_PADDING setting is there when you create a table, and can have an impact on the performance of some queries. If you are not careful, it can even hurt performance big time!” Examples and script follow.

In a post is called, For want of a nail, Michael Zilberstein writes, “I’ll describe here how small bug can ‘kill’ [a] strong server. The story begins when for some unknown reason [the] ‘rows’ column in [the] sys.partitions DMV begins to show 4.6 billion rows . . . ”

How many rows? asks Kalen Delaney, inquiring into how best to answer that question.

Here’s Adam Machanic with the release of Who is Active? v9.57, a “fast, comprehensive DMV collection” to answer this question: What’s Really Happening on Your Server?

Adam also provides a roundup of T-SQL Tuesday #001 (Date/Time Tricks).

In a similar vein, Dave Ballantyne gives a lesson in age calculation with SQL Server, sharing what he says is, “ . . . by far the simplest and accurate method that I know.”

Oracle

Let’s start the Oracle news with some reviews of the UKOUG Conference, which closed last weekend. Here are adhd ocd dba’s notes from UKOUG, and Marco Gralike’s UKOUG 2009 wrap-up: “The wifi was a minor bummer, but the rest was up on high standard as always. Good quality presentations as should be expected.”

Martin Widlake introduces, “ . . . a tuning method with partition exclusion where you infer a relationship between the value you want to limit a query on and the partition key. It takes a while to explain the theory so I am going to give it a name, in the vain hope it catches on . . .  I’m going to call it Correlated Partition Exclusion.”

From Igor’s Oracle Lab, Gary Myers brings the CREATE ANY TRIGGER three card trick, a security-related post.

The Oracle Performance and Backup Blog offers the first part of a series on Oracle RAC One Node, which is, “about a installation and configuration of Oracle RAC 11gR2 in One Node configuration on VMWare.”

Retuning to the My Oracle Support outcry, Hans Forbrich looks at MOS one week later, giving a break-down of improvements what remains wrong.

John Hallas gives a lesson on using glance to see Oracle process usage on HPUX.

To close things, here is Drupal guy Dries Buytaert on NoSQL and SQL. Dries writes, “Have a look at this video of Brian Aker’s great 10 minute lightning talk about NoSQL. NoSQL is a database movement which promotes non-relational data stores that do not need a fixed schema.  . . . NoSQL is an ‘and’ and not a ‘versus’. Plus, I expect the gap to close as there are a couple of interesting projects under way that bring some of the NoSQL advantages to the SQL world. One of them is Brian Aker’s own Drizzle project . . .  [Have] a look Brian’s NoSQL presentation. It’s funny!”

Also funny—Geert JM Vanderkelen’s Clusterious defined.

That is all. As always, I invite you to comment with your favourite DB blogs from the week gone by. Please return next week for Nick Westerlund’s LB#173. Till then!