sorted by: recent | see :
popular
Content Tagged with log + MySQL
Log Buffer #104: a Carnival of the Vanities for DBAs
Andrew Clarke has published to 104th edition of Log Buffer, the weekly review of database blogs, on Radio Free Tooting, marking LB’s second year. Happy Birthday, LB!
Log Buffer always needs editors, so if you you’d like to present your view of the week that was in DB blogs, contact me, the Log Buffer coordinator. You’ll be joining some of the best bloggers around, and making yourself and your blog a little better known to readers around the world.
And now, here’s Andrew Clarke’s Log Buffer #104.
P.S.: To our readers in the U.S. — Happy 4th of July!
Log Buffer #103: a Carnival of the Vanities for DBAs
Welcome to the 103rd edition of Log Buffer, the weekly review of database blogs.
Starting with Oracle stuff, Chen Shapira (just a simple DBA on a complex production system) is looking for great PL/SQL. Why? To become a better PL/SQL programmer. “But,” she writes, “for PL/SQL , I?m a bit stuck. I can still read my own code for bad examples, but where can I find examples for great code? . . . Somehow, there is simply no open-source code written in PL/SQL that I can read to get a good idea of how PL/SQL should be written.” Niall Litchfield recommends the contents of $ORACLE_HOME/rdbms/admin. Any other ideas to help Chen?
There was no shortage of people offering their help, as always. Beginning here on the Pythian blog, Grégory Guillou posted the fifth of his ten-part series on Oracle silent mode, this part covering adding a node to a 10.2 RAC. Says Grégory, “Even if you don?t leverage RAC?s ability to add or remove nodes to gain in agility, it?s still very likely you?ll come to these techniques when you want to upgrade some of your Servers or Operating Systems.” The post includes links to the earlier articles in the series.
On his Core IT for geeks and pros, Tanel Poder expounds another use case for WaitProf. He begins, “I recently diagnosed a performance issue where the ‘events in waitclass Other’ occasionally took significant part of the session?s response time. . . . So, what to do when this ‘events in waitclass Other’ wait becomes significant in the response time profile?” This is where waitprof, his custom tool, comes into play.
Jeff Hunter of the So What Co-operative posts Something to be aware of, Part II, in which he and Oracle Support tussle over NUMA in Linux, and where he is heard to say, “My next step is talking to a Duty manager. I really don’t want to do that.” And Part III, which Jeff begins, “I escalated my issue to a duty manager . . .”
On Oracle Applications DBA, Aviad Elbaz knows how to do tricks with a pipe, as he shows in his article on how to execute TKPROF on trace files larger than 2GB. Aviad, I think Bilbo and Gandalf would be proud.
Are you like me, shamefully ignorant about the whole Business Intelligence thing? Do you, too, secretly believe it might be an oxymoron? Mark Rittman is here to help, with an introduction to the Oracle BI Applications.
Vivek Sharma of Database/SQL Experiences informs us that he will be contributing a seminar on “Real Time Performance Tuning” to the very first event mounted by the IOUG (All India Oracle User Group). This is their TechNight, taking place in Hyderabad on Friday, July 18th.
Error Log Head-Scratcher
As an editor (of http://www.mysqlzine.net), I cringe at the title of this post. However, it is absolutely accurate. Recently, we had a situation where we had two servers running Sun Solaris 10 on some high-end Sun hardware. I don’t remember exactly, but it was one of Sun’s upper-end boxes with AMD procs. Nice boxes, really. The two servers are configured in a master-master circular replication setup.
Here is the problem. On both servers, the error logs were being created incorrectly. On one of them, it was creating an error log that was 154 megabytes in size. FLUSH LOGS worked, but the newly-created error log would be the same size. While there was some data in the file that I could use the cat, head or string command to discern, the majority of the file was not text data.
After working on this for a bit, I logged into the secondary server and discovered that the error log on this server didn’t look right either — the same characteristics of large size with almost no actual text data. The only difference is that these error logs were around 20 megabytes in size. I googled around a bit and couldn’t discover anyone with a similar problem.
I can’t figure out what was causing this. We checked everything we could think of, and during some other maintenance, restarted the mysqld daemon. That didn’t work either — when the server came back online it was experiencing exactly the same problem with the error log. Finally, during hardware maintenance to upgrade the memory, the servers were rebooted. The next morning, I checked them, and found both error logs working exactly as they should. However, it took that server reboot to fix the problem.
I am at a loss to explain what was wrong. If anyone has any thoughts or a similar experience, I would love to hear from you!
Log Buffer #102: a Carnival of the Vanities for DBAs
Welcome to the 102nd edition of Log Buffer, the weekly review of database blogs.
Since it was DB2’s 25th birthday this week, as Anant Jhingran reports, let’s start with it.
From ZDNet this week came a story that IBM was considering the open-sourcing of DB2 — big news, naturally, whether true or not. Matthew Aslett of 451 CAOS Theory says, Open source DB2? I don?t think so, suggesting that it was merely theorizing on the part of one IBM executive, and hype on the part of ZDNet. “Then of course,” Matthew continues, “there is the issue of why IBM would open source DB2. Where is the business driver? Despite solid competition from Oracle and Microsoft, the company is doing pretty well with DB2 as it stands, thanks very much, and open source databases have had minimal impact on the established vendors.”
Matt Asay of The Open Road likewise comes down on the uh-uh side of this. “It was . . . no surprise to see IBM quickly follow up ZDNet’s article with a blunt statement: ‘IBM has no plans to open source DB2.’ Of course it doesn’t. . . . The day that it needs DB2 to undermine Oracle’s database, however, we may see IBM making a similarly bald statement…in the other direction.”
On An Expert’s Guide to DB2 Technology, Chris Eaton offers some news on DB2 videos, including ChannelDB2’s video tutorials, IDUG’s video competition, and a funny video from IBM on the making of a “viral” industrial video. Such as itself.
On to MySQL now. Keith Murphy made his debut on the Pythian blog this week, with a link to some video tutelage of his own — his presentation to the Boston MySQL Users Group on backups. Jay Pipes also offers the slides for his address on Join-Fu: The Art of SQL (I and II). (I rarely cover presentation materials when I do Log Buffer, but these ones of Jay’s looks fantastic.)
Mark Schoonover reports that Keith’s and his 2008 MySQL Magazine survey is officially closed, adding, “Now the fun begins compiling all the data and pretty charts made. We’ve had 432 responses!”
Baron Schwartz of xaprb describes how to write a lazy UNION in MySQL. No, it doesn’t deal with posting a complaint about undefended job benefits. Baron explains: “Something occurred to me a couple of weeks ago: why not write a UNION that stops executing as soon as one part of it finds a row? Then you can UNION to your heart?s content and not incur the overhead of that second lookup unless you need it. For lack of a better term, I?m calling this a lazy UNION.”
Log Buffer #101: a Carnival of the Vanities for DBAs
Welcome the the 101st edition of Log Buffer, the weekly review of database blogs.
This edition was originally claimed by Ward Pond for his SQL Server Blog. Unfortunately, Ward is, in his own words, “dealing with the aftermath of a burst appendix,” which is a very good reason not to spend your time at the computer. Ward, heal up soon! We’ll see you on LB before too long.
In lieu of the normal Log Buffer, I throw it open to our readers. Please leave a comment mentioning your favourite database blog items from the week that was, and anything else you care to say about them.
LB will be back to normal next Friday. See you then!
Log Buffer #100: a Carnival of the Vanities for DBAs
Log Buffer, the weekly review of database blogs, is 100 editions (and almost two-years) old today! Lewis Cunningham has returned to LB to publish The Big 100th edition of LB on An Expert?s Guide to Oracle Technology.
No speech, but I would like to thank Log Buffer’s readers and especially all of Log Buffer’s editors for making LB a worthwhile and fun stop in the database “blogosphere”. It’s very easy to see why LB editors are successful in what they do — they are consistently enthusiastic, diligent, and adaptable. And I enjoy working with them.
Okay, okay — I can hear the orchestra starting to play me off, so let’s get to it. Here’s Lewis’s Log Buffer #100.
Log Buffer #99: a Carnival of the Vanities for DBAs
Welcome the the 99th edition of Log Buffer, the weekly review of database blogs.
Since PGCon recently happened right here in Ottawa, let’s start with some posts about it, and about PostgreSQL. Josh Berkus came to the conference with his Database Soup. It sounds like he enjoyed himself: “So, that’s pgCon. It was exciting and fun. All of you PG geeks who missed it should be kicking yourselves about now, and putting in budget requests for next year.” He has day one highlights; day two highlights, and also some photos from the conference.
On Tending the Garden, Selena Deckelmann (who knows a thing or two about Postgres conferences) has her PGCon review, with links to conference webpages.
Robert Treat of zillablog also has his take-aways. “The biggest thing to come out of this past week to me was recognition of the continued growth of the postgresql community. With a number of regional conferences springing up over the past year, I wondered if PGCon would be able to match the experience from last time, and was happy to see that it far exceeded it. . . . One thing I noted was that we have a very large presence of Postgres in Ottawa, I think larger than what we had at PGEast for the Baltimore/Washington Area.”
On Greg’s Postgres stuff, Greg Sabino Mullane has an item on verifying master-slave replication with check_postgres.pl, a montoring script for Nagios and other systems.
Hubert Lubaciewski of select * from depesz; looks at different approaches to counting the number of distinct elements, such as distinct sessions per day.
On An Expert’s Guide to Oracle Technology, Lewis Cunningham examines the recent news of the worlds largest database running on Postgres. How large? 2 Petabytes! “Let’s put that in perspective,” writes Lewis. “1 petabyte is 1,000,000,000,000 bytes. Yahoo has two of those. . . . [They use] this database to analyze the browsing habits of its half a billion monthly visitors. How would you like to tune those queries?” Lewis also notes that this is not the plain-vanilla PostgreSQL that you or I would download and run on our website box.
There are conferences on the horizon of the Oracle world too. Dan Norris reminds us that ODTUG is just around the corner. That’s the Oracle Developer Tools User Group’s Kaleidoscope 2008 event, taking place in mid-June in New Orleans.
Gareth Roberts of In Depth Apps announces the call-for-papers of the New Zealand Oracle Users Group’s (NZOUG) 2008 conference, coming in October.
In other Oracle matters — Chen Shapira, just a simple DBA on a complex production system, has some thoughts on cumulative distribution. “How do we calculate Cumulative Normal Distribution? This means calculating the probability that a random variable from a normal distribution, will end up equal to or less than X.”
Log Buffer #98: a Carnival of the Vanities for DBAs
The 98th edition of Log Buffer, the weekly review of database blogs, has been published on Jeff’s SQL Server Blog.
Log Buffer is a shared project of the DBA blogging community, so you’re welcome to edit and publish an edition yourself. LB’s 100th anniversary edition is still up-for-grabs (and there’s plenty of room besides that), so read the Log Buffer homepage and the guidelines, and then email me.
Here’s Jeff Smith’s Log Buffer #98.
Log Buffer #97: a Carnival of the Vanities for DBAs
The 97th edition of Log Buffer, the weekly review of database blogs, has been published on Brian “Krow” Aker’s Idle Thoughts.
We have Jeff Smith and Ward Pond standing by for two upcoming editions. And if you’d like to contribute, make yourself known in the DBA community-at-large (and have some fun in the process), you too can do Log Buffer! Read the homepage and send me, the Log Buffer coordinator, an email.
And now, Brian Aker’s Log Buffer #97.
Log Buffer #95: a Carnival of the Vanities for DBAs
The 95th edition of Log Buffer, the weekly review of database blogs, has been published by Mark Schoonover on his Mark’s IT Blog.
We can look forward to LB#98 Jeff Smith’s Jeff’s SQL Server Blog on May 23rd. There’s always plenty of room for more editors, so don’t waste another minute — send an email to me, the Log Buffer coordinator, and get started!
Without further ado, here is Mark Schoonover’s Log Buffer #95.
When SHOW SLAVE STATUS and the error log Disagree
Or, When MySQL Lies!
When I do a show slave status\G, sometimes mysqld will lie to me and give me a wrong Exec_Master_Log_Pos. Let me explain with a situation from last night.
This is the output of show slave status\G from mysql version 5.0.41-community-log:
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: XXX.XXX.XXX.XXX
Master_User: replic_username
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000480
Read_Master_Log_Pos: 690470773
Relay_Log_File: db2-relay-bin.000028
Relay_Log_Pos: 683977007
Relay_Master_Log_File: mysql-bin.000480
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error: Could not parse relay log event entry. The possible reasons are: the master’s binary log is corrupted (you can check this by running ‘mysqlbinlog’ on the binary log), the slave’s relay log is corrupted (you can check this by running ‘mysqlbinlog’ on the relay log), a network problem, or a bug in the master’s or slave’s MySQL code. If you want to check the master’s binary log or slave’s relay log, you will be able to know their names by issuing ‘SHOW SLAVE STATUS’ on this slave.
Skip_Counter: 0
Exec_Master_Log_Pos: 126
Relay_Log_Space: 690471192
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: NULL
So in summary, the slave SQL thread is stuck (in this case because of a problem during the transfer of the binlog data to the slave’s relay log). The show slave status\G command tells me that it is stuck at the master binlog file mysql-bin.000480, position 126.
But, if I look at the error log file entries when the slave got stuck I see:
Log Buffer #94: a Carnival of the Vanities for DBAs
Log Buffer, the weekly review of database blogs, welcomes back for his record-breaking record-tying (Sheeri, are you reading?) third edition Ronald Bradford of Opinions, Expertise, Passion.
Why does Ronald write Log Buffer? Perhaps it’s because he knows that LB is and established and widely read feature, and hence likely to bring his own blog some new readers and improve its ranking. Or maybe he enjoys the fun and challenge of comprehending and presenting the entire DBA blog scene, not just the part that deals with his own favoured technologies. (Or maybe he just likes me? Ronald?)
Since Log Buffer is open to anyone, I encourage you also to join in. If you’d like to edit and publish an edition yourself, take a look at LB’s homepage, read the few guidelines, and then get in touch with me, the Log Buffer coordinator.
You can also contribute by emailing your favourite blog items to the editor.
And now, here’s Ronald Bradford’s Log Buffer #94.
Log Buffer #93: a Carnival of the Vanities for DBAs
Welcome to the 93th edition of Log Buffer, the weekly review of database blogs.
Conference season is upon us, so it’s been a busy week. There was the MySQL Conference & Expo, so let’s look at that.
Arjen Lentz posts about Sunday’s community dinner, including the arrival of an unexpected guest. Two photos: one of Pythian’s Paul Vallée getting some Sun; the second from the pre-conference dinner.
Zack Urlocker has a couple pieces with both photos and links to video of the keynote addresses from Marten Mickos, Jonathan Schwartz, and Rich Green. From Wednesday, and from Thursday.
Congratulations are due to Baron Schwartz, Diego Medina, and Sheeri Cabral. Baron reports from the conference that the three of them were awarded the 2008 MySQL Community Awards, and his piece makes for a very apt acceptance speech. Here’s Kaj Arnö’s more official post on the Community Awards.
Baron also has good summaries of the conference course: day one, and day two.
Elsewhere on the MySQL scene, much ado about the immediate roadmap for the DBMS, as introduced at the conference. Jeremy Cole got things going, writing, MySQL to launch new features only in MySQL Enterprise: “MySQL will start offering some features . . . only in MySQL Enterprise. This represents a substantive change to their development model ? previously they have been developing features in both MySQL Community and MySQL Enterprise. However, with a shift to offering some features only in MySQL Enterprise, this means a shift to development of those features occurring . . . only in MySQL Enterprise.” This post got a lot of comments, including from MySQL boss Marten Mickos.
Log Buffer #91: a Carnival of the Vanities for DBAs
Welcome to the 91st edition of Log Buffer, the weekly review of database blogs.
For a change, let’s begin with some PostgreSQL stuff. On Tending the Garden, Selena Deckelmann gives her retrospective thanks to those who attended and presented the PostgreSQL Conference East.
On Esoteric Curio, Theo Schlossnagle gives his thoughts on the keynote address by Joshua Drake, touching on the perennial versus, Postgres vs. MySQL.
Hey, there was a MySQL ambassador there, too — Baron Schwartz of xaprb. Here’s Baron’s recap of his experiences at the conference.
When pet projects bite back! reasserts that SQL is in fact a programming language. Sometimes one can forget that and need a little reminder. Or a not-so-little reminder, such as a three-pages-long query. The discussion ranges into questions of design, a matter that Baron Schwartz also pursues: he asks (on behalf of his wife), what is your favorite database design book? (I want to know too — um, for . . . a friend of mine.) Lots of good responses so far.
For huge queries to huge tables. On the MySQL performance blog, Aurimas Mikalauskas walks us through using MMM to ALTER huge tables. He writes, “When it comes to changes that really require table to be rebuilt - adding/dropping columns or indexes, changing data type, converting data to different character set - MySQL master-master replication especially accompanied by MMM can be very handy to do the changes with virtually no downtime.”
Log Buffer #90: a Carnival of the Vanities for DBAs
Welcome to the 90th edition of Log Buffer, the weekly review of database blogs.
First, SSQA.net’s SQL Master offers his walk-through of best practices for installing SQL Server 2005, with clustering as the destination.
If you read SQL Server blogs, you already know Adam Machanic. I’m very pleased to mention his first post for the Pythian Group blog, covering the basics of minimal logging and its enhancements in SQL Server 2008.
Also looking at Katmai was Bob Beauchemin, with his tip on accessing multiple servers with the SQL Server 2008 PowerShell provider, something right out in the open that nonetheless you might have missed.
Bob also figures out a little more about 2008’s new sparse columns and column_sets.
Joe Webb’s site mentions his appearance on Buck Woody’s Real World DBA podcast, where they tackle the question, does JOIN order matter?
On OraStory appears a very-commented post by Dominic Brooks, tantalizingly called, The dea(r)th of Oracle RDBMS and contracting?. From the piece: “I feel like the war has been lost and there are only a few pockets of resistance left now, resistance that will sooner or later be squashed. The database is under attack. . . . A newly created hierarchy have decreed that databases are indeed bad. . . . And I was speaking to a friend today at a previous employer, a major media / entertainment company. They are planning to abandon their pragmatic approach to Oracle and switch wholely [sic] to open source databases, ORM tools, and the like.”
And speaking of “Oracle versus X” (why doesn’t HTML have a <segue> tag?) — in last week’s LB#89, Shakir Sadikali criticized a post by Sean McCown’s Database Underground that compared Oracle and SQL Server to the latter’s advantage. Sean follows up the original piece, with this second item on Oracle’s community. He writes, “. . . one area I think Oracle has it over Microsoft is in its downloads. When I go to Oracle to download anything, all the downloads are clearly marked on a single page. Microsoft just isn’t like that. Sometimes even finding a service pack for SQL is like finding help for Oracle. . . . to those of you who said Oracle is easier to admin that SQL, you’re just crazy.”