Welcome to Tip #1 in MySQL Replication Series. In this tip we will go over what to do when you only want to replicate certain data to slave(s). Most general way to tell what is replicated to which slave is to include following configuration directive in my.cnf file depending on your environment and your goals. We will start with slave server side options since you have more flexibility on slave on what to replicate and what not to.

Slave server options:

• replicate-do-db = dbname (or) replicate-do-db = dbname1, dbname2, …, dbnameN
  This option is used on slave server to tell the server to only replicate dbname db on this particular host. You would want to use this if you have a master which is replicating to multiple slaves and each slave may contain different database for read performance reasons.
• replicate-ignore-db = dbname (or) …

Doing Billions of Queries per Day
Read this doc on Scribd: DVPmysqlucFederation at Flickr: Doing Billions of Queries Per Day

Whenever I work at a place I do the following.

Get a rundown of what the application is, what its demands are, what does the company expect the application to be a year from now - like how many users are going to use the application. 10 million, 20 million, 100 million?

Then I find all the slowdowns:
- What are the my.cnf settings?
- What are the most active tables?
- What type of SQL is being used?
- How is the data accessed?
- Who/What owns the data?
- What is the Read-Write Ratio?
- How many servers are used now to handle the site load, and how many are needed within a few months.
- What is the reads per second, connections per second, writes per second
- How does the data grow? MxN, MxNxO, N^4 etc.

Once I get this down (a few days) then I change everything :)

If the data is small and doesn't change often I don't bother …

At the end of the first day of the MySQL conference and expo I caught up with Marten Mickos former MySQL CEO and current Sun Database SVP.   Marten was in high spirits and eloquent as always.

My interview with Marten (10:29)  Listen (Mp3)   Listen (ogg)

Marten worked the floor like the consummate host he is. 

Some of the topics we tackle:

• How he felt …

Yup, the presentation slides as well as the scripts are now available online on the conference website.

The stuff you will find in there:

Information_schema.pdf

Diagram of the information schema

I_S_VC_Slides.pdf

Slides for the UC presentation, "Grand Tour of the Information Schema"

I_S_INDEXES2.sql

script, returns one row for each index (rollup of information_schema.STATISTICS)

I_S_REDUNDANT_INDEXES2.sql

script, lists all redundant indexes. Redundancy rules:

• 
  
• two indexes with the same columns, type and uniqueness are interchangeable. The one with the largest index name is listed as redundant
  
• if there is a unique …

This morning I landed back at my home airport, EWR, after spending a fun-filled week and a half at the MySQL Conference 2008.

This year's conference was the best ever for me. I have a lot of people to thank and a lot to blog about. The number of pings I have received about lack of my blogging during conference is truly humbling. However, I did have a good reason for not being able to blog.

First, I was presenting three sessions, with two on the final day of the conference. Since I have the habit of continuously revising my presentations, that put a little bit of pressure on me. A big thanks to all those who came to my sessions.

Second, I was given a great opportunity to be a keynote panelist at the "Scaling up or out" …

Several months ago I was invited to a special FOO camp at the O'Reilly Campus, about social networking and the social graph. One of the things that the ora people did was record an interview video of each attendee. They've now put all those videos up on youtube.

Here is mine.

Have you ever executed a query from the MySQL command line client only to find that the output wrapped and the result is unreadable? In the past you have to run the query again with \G instead of ; or \g to get it to display the output in a vertical mode. My feature in MySQL 6.0.4 fixes that. The auto-vertical-output option tells the command line client to display the results in vertical format if the results are going to be too wide to display horizontally. It does this without re-executing the query because MySQL passes the length of each column in the result set. If the client isn’t able to determine the width of the screen it will default to 80 chars.

DTrace Integration with MySQL 5

On April 15-16, we demoed a few DTrace probes for MySQL 5.0 integrated with Chime visualization Tool at MySQL users conference 2008. Here is an snapshot of the DTrace probes in chime showing the query execution time/count in Chime tool:

The DTrace probes inserted into MySQL 5.0 in the demo are:

provider mysql {
    probe data__receive__start(int);
    probe data__receive__finish(int);
    probe query__plan__start(char *);
    probe query__plan__finish(char *);
    probe query__execute__start(void *, char *, char *, …

Just updated the datagrid so if you don't specify an ORDER BY clause, ordering will be disabled. You can if you wish either not specify an ORDER BY clause (in which case ordering will be disabled), or you could specify one to get your rows ordered how you want, and then set the allowSorting property to false to disable ordering.

Bear in mind that this is the development version, but it will probably be released soon.