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I had a problem with slave replication, every now and then we would get an error which manually had to be resolved

We used Set Global sql_slave_skip_counter = 1; start slave;

You might also get some of those when you set up a new slave using a mysqldump. If from the time you started the mysqldump and by the time it finished, some lines were added to the bin logs or you started it at the wrong position, then you would get some duplication errors.

While it looks concerning, don’t panic. You can fix it by skipping the lines that are duplicates, although it’s not an ideal situation.

Now if you want to completely avoid errors, or specifically duplicates and you are sure that the odd ones that …

In my server error log i see090415 10:55:57 [Warning] Aborted connection 481 to db: 'db' user: 'user' host: 'localhost' (Got timeout reading communication packets)090415 10:56:16 [Warning] Aborted connection 582 to db: 'db' user: 'user' host: 'localhost' (Got timeout reading communication packets)090415 11:05:13 [Warning] Aborted connection 2693 to db: 'db' user: 'root' host: 'localhost' (Got

Sure, you've heard it before: [some company's logo] has a new MySQL backup tool that promises to solve all of your data recovery needs. The good news is most of these tools work pretty well. However, they tend to suffer from a similar set of limitations. Most require sophisticated infrastructures or complex setup and maintenance and can become a resource drain for some organizations. You're probably wondering, "Why can't someone build a fully automated MySQL backup solution that you can just turn on and forget?"

I am happy to say that the MySQL Developers at Sun are doing just that. In fact, a prototype will be demonstrated at the 2009 MySQL Users' Conference that will show the feasibility of a fully automated MySQL backup and recovery tool. It's being called the MySQL Time Machine and (with all due respect to all vendors with products of similar names) it allows you to recover your data using a datetime value. How cool is that? Even MySQL …

Sure, you've heard it before: [some company's logo] has a new MySQL backup tool that promises to solve all of your data recovery needs. The good news is most of these tools work pretty well. However, they tend to suffer from a similar set of limitations. Most require sophisticated infrastructures or complex setup and maintenance and can become a resource drain for some organizations. You're probably wondering, "Why can't someone build a fully automated MySQL backup solution that you can just turn on and forget?"

I am happy to say that the MySQL Developers at Sun are doing just that. In fact, a prototype will be demonstrated at the 2009 MySQL Users' Conference that will show the feasibility of a fully automated MySQL backup and recovery tool. It's being called the MySQL Time Machine and (with all due respect to all vendors with products of similar names) it allows you to recover your data using a datetime value. How cool is that? Even MySQL …

Sure, you've heard it before: [some company's logo] has a new MySQL backup tool that promises to solve all of your data recovery needs. The good news is most of these tools work pretty well. However, they tend to suffer from a similar set of limitations. Most require sophisticated infrastructures or complex setup and maintenance and can become a resource drain for some organizations. You're probably wondering, "Why can't someone build a fully automated MySQL backup solution that you can just turn on and forget?"

I am happy to say that the MySQL Developers at Sun are doing just that. In fact, a prototype will be demonstrated at the 2009 MySQL Users' Conference that will show the feasibility of a fully automated MySQL backup and recovery tool. It's being called the MySQL Time Machine and (with all due respect to all vendors with products of similar names) it allows you to recover your data using a datetime value. How cool is that? Even MySQL …

This is an issue that keeps rearing its ugly head over and over again, and since it greatly affects performance, it is most important that DBAs of any DMBS running on Linux come to grips with it. So I decided to do some research and try different settings on my notebook. Here are my findings.

What can you find on the web?

A Wikipedia search for the word swappiness will come up empty (any volunteers out there want to write an article?). A Google search will show some pretty old material—the best article I found is from 2004: Linux: Tuning Swappiness. This article includes a detailed discussion with some interesting remarks by Andrew Morton, a Linux kernel maintainer.

So, what is swappiness?

Towards the end of the email thread quoted in the article, you’ll find this definition (sort of):

> I’ve read the source for where …

Last few weeks I noticed a problem in the replication, where on and off the replication SQL thread fails to truncate a table with the following error:

      ERROR 1105 (HY000): MyISAM table 'XXXX' is in use (most likely by a MERGE table). Try FLUSH TABLES.

So, I was keep skipping the error, as it was fuzzy why when only one thread is actually executing (no other threads on DB other than slave SQL thread); and today it happened, and I got a simple repro:

 
mysql> drop table if exists t1, t2, merge;
Query OK, 0 rows affected, 3 warnings (0.05 sec)
 
mysql> create table t1(c1 int)Engine=MyISAM;
Query OK, 0 rows affected (0.03 sec)
 
mysql> create table t2(c1 int)Engine=MyISAM;
Query OK, 0 rows affected (0.06 sec)
 
mysql> insert into t1 values(10);
Query OK, 1 row affected (0.04 sec)
 
mysql> insert into t2 values(20);
Query OK, 1 row …

mysqlsla is interesting tool to analyze slow log query, aggregate same query in one and generate unique sql statement withCount, (max, min, avg) execute time, lock time, Rows sent, Rows examined for each unique one.you can use it to review indexes and drop unused index, and create another.Report for slow logs: slowquery1day.txt791 queries total, 85 uniqueSorted by 't_sum'Grand Totals: Time 23.05k

Here are some common performance tuning concepts that I frequently run into. Please note that this really is only a basic introduction to performance tuning. For more in-depth tuning, it strongly depends on your systems, data and usage. Server Variables For tuning InnoDB performance, your primary variable is innodb_buffer_pool_size. This is the chunk of memory that InnoDB uses for caching data,

Problem With the release of MySQL 5.1, many DBAs are going to be scheduling downtime to upgrade their MySQL Server. As with all upgrades between major version numbers, it requires one of two upgrade paths: Dump/reload: The safest method of upgrading, but it takes out your server for quite some time, especially if you have a large data set.mysql_upgrade: A much faster method, but it can still be