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Re: Severe Memory Loss
Posted by: Steve Williams
Date: November 30, 2005 11:43AM

1.) The server is running on Linux 9.0, Apache_1.3.33, php-4.3.10, & MySQL-Max-3.23.58-1a

1a.) all the database tables are MYISAM. and are auto incrementing with a primary key.
(See extra config Info.)

# COnfig (my.conf) #

innodb_data_file_path = ibdata1:10M:autoextend:max:1998M
set-variable = innodb_buffer_pool_size=30M
set-variable = innodb_additional_mem_pool_size=8M
set-variable = innodb_log_file_size=16M
set-variable = innodb_log_buffer_size=8M
innodb_flush_log_at_trx_commit=1
set-variable = max_allowed_packet=5M

# End COnfig (my.conf) #

2.) When restarting the MySQL server (mysqld),
It does not free any of the memory that was used during calls made from PHP.

It only releases the "table Cache" memory In order to free the memory we need to restart the whole server.
We have verified that Apache is releasing memory AFTER it has displayed the page.

3.) After I restart the server (the whole machine,not the MySQL server),
and then access a table, by running a querry, adding a column (field),
then the memory is allocated but is not recovered.

The amount of memory allocated varies depending on the amount of "output Data"
that has to be displayed in the browser.
The greater the amount of information, the greater the memory allocated.
But once that page (or browser) is closed it should return the memory to "free",
However, it remains as "actv" or "used" by the server resource(s)
(See resource Monitor Example.)

### Start Example Resource ###
Mem: 2064552k av, 708600k used, 1355952k free, 0k shrd, 45152k buff
616376k actv, 22320k in_d, 29200k in_c
Swap: 2048276k av, 0k used, 2048276k free
### End Example Resource ###

MySQL starts with 58meg of memory pre-allocated to the Server.(Per config above)
##
1218 mysql 15 0 60060 58M 2036 S 0.0 2.9 0:00 0 mysqld-max
##

It maintains its pre-allocated amount, but as calls are made it begins to "bloat" and not release.
This is after 2 hours:
##
1218 mysql 15 0 60060 74M 2036 S 0.0 2.9 0:00 0 mysqld-max
##


4.) I will give you two examples of tables that this is happening on.

4a.) A table that is 182 Megs on disc, and has one indexed column. (contains about 500,000 records)

4b.) The other table is a 972 meg table with no indexed comumns, however it contains a long blob column (field).
(contains about 46,000 records)

5.) When accessing a very small table, it uses about: 160k of Memory.

6.) I was told we are not using "keycache" on our server.



Thanks,

Steve Williams

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