MySQL 5.1 (which is in beta right now btw) will have an interesting new feature called partitioning which will allow for a bit more scalability in certain situations. You can read more about it here, here, and here.

I don't see this really being much of an advantage in practice. Most people want to scale their database in terms of transactions per second. You could buy three disks and put a partition on each or you could put the whole thing on a stripped RAID array. Each would have the same IO characteristics (assuming your …

Lots of people at MySQL like Skype, because they find it easier to use than straight VoIP. I'm not so happy:

• Skype is a proprietary protocol. Sure, they're charging hardly anything for it—at the moment. But once you're locked in to that kind of protocol, it's difficult to change. I doubt that Skype will ever get really expensive, but there's a danger.
• For a dyed-in-the-wool computer person like me, using GUIs to interface is counterproductive. Would you want a telephone with a mouse on it? Probably not. Then why do that with a modern replacement? I'd be much happier with a command line interface which enables me to do things like:

  skype> call Caltabvin Sun
  

  Here the text in bold is that I enter (Cal), and the tab completes the name. So much easier than scrolling through menus with names or even photographs. …

After getting tired of waiting for the MySQL folks to add features to FULLTEXT and to make it work on InnoDB, I decided to do it myself. I’ve just finished sqlsearch 1.0.0. Features:

• ENGINE-independent (requires triggers)
• Uses fast, full-word indexed searching
• Multi-table and multi-column indexes supported
• Supports “quoted strings” and +/- logical operators in search queries
• Gives search query feedback, including why some terms were ignored
• Provides typo and phonetic suggestions for words which don’t appear in the index
• Supports weighting of “sources” (tables or fields) and “ids” (rows)
• Supports link information …

In the deadlock section, innodb shows:


what the last deadlock was

what the deadlocks state was

what the deadlock lock was holding

and what they were waiting for


060718 8:00:18
*** (1) TRANSACTION:
TRANSACTION 4 4095301271, ACTIVE 0 sec, process no 19925, OS thread id 387040248038 starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 368
MySQL thread id 2287022118, query id 5904669207 [HOST] [user] Searching rows for update
/* /PHPFILE: PHP FUNCTION() */ UPDATE Latest SET `date_create`='?', `id`='?' WHERE user_id=?
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 6669281 n bits 608 index `user_id` of table `DB/Latest` trx id 4 4095301271 lock_mode X waiting
Record lock, heap no 38 PHYSICAL RECORD: n_fields 3; 1-byte offs TRUE; …

A summary from the mySQL Performace Blog

Innodb takes averages over time and displays its numbers which are hard to figure out what a true average is from some sort of polling method.


----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 28655958, signal count 25483315
Mutex spin waits 1468249294, rounds 5838311115, OS waits 20658052
RW-shared spins 4676021, OS waits 1740480; RW-excl spins 13056306, OS waits 2135090


• 
  
• reservation count - counter for the sync array when slots are added to it
  
• signal count - counter for the sync array for when threads are signal for use
  
• OS Waits - used for exclusive and shared locks, and relates to …

Hello,

Although not MySQL Cluster specific, I am interested in speaking to developers or administrators about Web 2.0-type applications they are working on or actively support that use MySQL or MySQL Cluster in some capacity.

Please email me directly,

Jimmy Guerrero
Sr Product Manager
jguerrero@mysql.com


--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
Main thread process no. 25100, id 114696, state: sleeping
Number of rows inserted 200059954, updated 1278003724, deleted 130588363, read 47473646817
37.99 inserts/s, 1718.43 updates/s, 0.33 deletes/s, 5470.51 reads/s


This section shows innodb thread queue status and the state of the main thread.

I spent a productive hour with Krugle yesterday, meeting with a few members of management: Steve Larsen (CEO), Laura Merling (VP, Business Development - yes, that Laura Merling), and Ken Krugler (CTO). I have to admit: I went into the meeting with low expectations. In Ken's words, I figured a vertical search engine focused on open source and development might be interesting, but not useful (with "use" translating into dollars).

I was wrong.

First off, Krugle is more than a vertical search engine. It does that, and it does it extremely well. Krugle aggregates the many and various open source software repositories (Sourceforge being just one of them), indexes them, and makes them easily, productively searchable. So, if I know I need a utility to convert documents …


----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 13505821346; in additional pool allocated 17936896
Buffer pool size 768000
Free buffers 5
Database pages 728656
Modified db pages 108067
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages read 31203802, created 3930786, written 131784156
4.50 reads/s, 0.00 creates/s, 131.22 writes/s
Buffer pool hit rate 1000 / 1000


Pending reads and writes are pending requests on buffer pool.
Different types of IO are used by Innodb, think of it like a IO scheduler for INNODB itself.

LRU pages - dirty pages which were not accessed long time
flush list - old pages which need to be flushed by checkpointing process
single page - independent page writes.


---
LOG
---
Log sequence number 1039 3161691821
Log flushed up to 1039 3161691821
Last checkpoint at 1039 2401802667
0 pending log writes, 0 pending chkp writes
222872631 log i/o's done, 56.99 log i/o's/second


• 
  
• Log sequence number is the number of bytes written to the buffer pool.
  
• Log flushed up to is the number of bytes that has been flushed or unflush (sequence number - log flushed up to)
  
• Last checkpoint is a fuzzy line of what was flushed to logs ie recovery line for a crash (from my understanding).
  

Then there is some cool stats on log writes which should remain low.

Tuning
If you see more than 30% of log buffer size being unflushed (Log flushed up to) increase it if possible.