avoiding "Locked" threads

[Jon Drukman]

I've got a very high traffic discussion forum database that is 
constantly running into a problem with lots and lots of threads in the 
"Locked" state.  i was under the impression that MySQL could 
update/insert and select from the same table at the same time, but it 
doesn't seem to be the case.  all tables are MyISAM.  the machine is a 
dual xeon 3.2G with 2G of RAM now but i am upgrading it to 4G.  the 
database is on a 15K RPM SCSI RAID0+1.  the cpu load and io load all 
looks pretty good.  here's my my.cnf:

[mysqld]
set-variable    = query_cache_size=384M
set-variable    = key_buffer=384M
set-variable    = max_allowed_packet=4M
set-variable    = table_cache=64
set-variable    = sort_buffer=8M
set-variable    = record_buffer=8M
set-variable    = thread_cache=8
set-variable    = tmp_table_size=128M
set-variable    = thread_concurrency=4
set-variable    = myisam_sort_buffer_size=128M
set-variable    = max_connections=1800
set-variable    = max_connect_errors=100000
set-variable    = wait_timeout=120
set-variable    = max_binlog_size=500000000
set-variable    = long_query_time=5
server-id    = 1
log-bin=/var/opt/mysql/db2-binlog
skip-innodb
log-error=/var/opt/mysql/db2-errlog
here's a sample of some of the locked threads at the moment:

INSERT INTO MSGPOST VALUES (NULL, '931046', 'leon 
is...<br/><b>(SPOILERS)</b><br/>-<br/>-<br/>-<br/> |
INSERT INTO MSGPOST VALUES (NULL, '943738', 'All I got is from the 
British. It should be the same th |
INSERT INTO MSGPOST VALUES (NULL, '951538', '(i)Don\'t forgot that 
Florina can BARELY hold a slim la |
INSERT INTO MSGPOST VALUES (NULL, '955788', 'it stands for cyberathletic 
amateur league<br/>---<br/> |
INSERT INTO MSGPOST VALUES (NULL, '971210', 'I\'m getting a job at a 
place that sells DnD books and  |

SELECT * FROM MSGPOST WHERE MsgPostId = 4466518 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466519 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466523 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466524 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466526 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466527 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466532 

SELECT * FROM MSGPOST WHERE MsgPostId = 4466534

we've tried using MERGE tables on some of the real busy ones to break up 
the updates but we're still seeing locks doing SELECT on the merged table.

any ideas appreciated!

-jsd-

--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe:    http://lists.mysql.com/[EMAIL PROTECTED]