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First thoughts on Leopard

Term Hallelujah! They finally added tabs. I've been using iTerm for years now for this reason, and while it has gotten better, it still crashes a lot. I have no idea why it took Apple this long to fix this.

From Row They are now including this on all Macs. About time...

Safari The new find feature makes find useable on web pages. Simple interface change but it overall quite nice. The "copy part of a page is dashboard" will either turn out to be one of my new favorite features, or I will forget about it completely. I've made a copy of some of the reporting widgets out of Google Analytics (which was cake to do). This has the potential to make Dashboard useful for me.

Time Machine I am finding myself a little bit scared of this one. It keeps all of its backups in some sort of uncompressed database. I am not sure how the Restore is supposed to work, and not being able to just copy …

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Funny command line option for the day

I needed to start mysql without privileges after a database restore today, and while confirming the correct option which was –skip-grant-tables I came across an option which made me laugh.

$ mysqld --verbose --help
...
  --sporadic-binlog-dump-fail
                      Option used by mysql-test for debugging and testing of
                      replication.
...

And here is the Official Manual Entry

How to Recover Deleted Oracle Datafiles with No Downtime

So you have accidentally removed a datafile from your production database? First thing, DON’T PANIC! There’s an easy way to recover deleted datafiles, for as long as your database remains up. The procedure below works on linux, however this method conceivably can work for other platforms. This procedure will even work if your database is [...]

MySQL Conference Submissions have closed

If you didn’t get your proposal in for MySQL Conference 2008 , that’s too bad.

I often wondered from past conferences why submissions were needed so early, like 5 months before. Well, as being invited to be part of the MySQL Conference committee this year I now know why, and have a greater appreciation. With near 300 submissions, it takes time to review them, and this is just the first step in a number to get to a completed schedule for next years conference.

Also getting a sneak preview of what’s to come is really cool! I’m already excited.

MySQL Conference Submissions have closed

If you didn’t get your proposal in for MySQL Conference 2008 , that’s too bad. I often wondered from past conferences why submissions were needed so early, like 5 months before.

TheoryCraft - Breaking down elements into blocks

So I have been doing some more research about Oracle - Database-assisted Web Publishing using Java Stored Procedures from my last post and I've tried to implement it into more manageable chunks.
I mean, you can save processed data (data that has already been calculated and/or had some business/application logic applied to it) in the WebCache and then re-use it instead of contacting the database over and over again. The theory here is sound, but even in the white papers on the subject, there has been some reluctance about whether the cache hits will benefit the overall performance or hinder it.


The Downside of Caching

From my experience, its sometimes impractical to save processed data. For …

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Filtered MySQL Replication

To get this straight - I'm not a big fan of filtered or partial MySQL Replication (as of version MySQL 5.0) - there is enough gotchas with replication itself and getting things right with filtering can get quite bumpy road. In some applications however it is very helpful so lets see what one should do or should not do to make it work.

Experience shared here mainly applies to logical level replication. MySQL 5.1 can use row level replication which alleviates some of these issues but I guess it will still take some time before it becomes massively used.

First thing you need to know about partial replication - you can do filtering on the Master or on the Slave. Filtering on the Slave is normally preferred as in this case you get full binary log on the Master which is not only helpful for replication needs but also if you ever need to do roll forward recovery while recovering from backup. There are however some cases when you really …

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Explaining InnoDB graphs for MySQL Administrator

Regarding my last post MySQL Administrator useful InnoDB graphs here are the explanations of some of the graphs.

idb storage page

  • reads graph: number of reads; it monitors if the system is under heavy or light read access.
  • pending reads graph: number of pending read requests to the underlying data file (the database must wait to gain access). If this value increases it could indicate serious contention issue. Seeing this graph always close to the bottom line it’s very good.
  • writes graph: number of writes; it monitors if the system is under heavy or light write access.
  • pending writes graph: number of pending write requests to the underlying data file. If this value climbs requires attention. Seeing this graph …
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LOAD DATA INFILE - performance case study

I often noticed that people complain about the LOAD DATA performance when loading the table with large number of rows of data. Even today I saw a case where the LOAD DATA on a simple 3 column table with about 5 million rows taking ~15 minutes of time. This is because the server did not had any tuning in regards to bulk insertion.

Consider the following simple MyISAM table on Redhat Linux 32-bit.

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CREATE TABLE load1 (
  `col1` varchar(100) NOT NULL DEFAULT '',
  `col2` int(11) DEFAULT NULL,
  `col3` char(1) DEFAULT NULL,
  PRIMARY KEY  (`col1`)
) TYPE=MyISAM;

The table has a string key column. Here is the data file( …

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MySQL - Large File Support

Today I had an interesting issue from one of the internal property within Yahoo!, where they were not able to start the MySQL server after the server has been upgraded to 5.1 from 4.1.

Here is the error log when the 5.1.22 server has started on 32-bit RHEL:

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      071105 12:25:50  INNODB: Operating system error number 27 IN a file operation.
INNODB: Error number 27 means 'File too large'.
INNODB: SOME operating system error numbers are described at
INNODB: http://dev.mysql.com/doc/refmastartn/5.1/en/operating-system-error-codes.html
INNODB: File name /mysql/var/mysql/ibdata/ibdata1
INNODB: File …
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