MySql Error when trying to delete a blog entry

[khalid]

When I go to the blog entries of the member and highlight one entry and then hit "Delete" button, I get mysql error message:

Database error in vBulletin 3.8.4:
Invalid SQL:
  SELECT COUNT(DISTINCT userid) AS total
  FROM blog WHERE state = 'visible';
MySQL Error   : Out of memory (Needed 8388580 bytes)
Error Number  : 5 

I then ssh to my server and ran this query from within and got the same error. If I take "count" out of the query, I get the results without any problem. I mean if I run the following query, I dont get any problem:

  SELECT DISTINCT userid AS total
  FROM blog WHERE state = 'visible'; 

I am using VB 3.8.4 PL2 and Blog 2.0.2.

Can someone help please.

[Trevor Hannant]

The query itself is the problem here as such - as you've found by running it yourself. The problem here is this line:

[FONT=Courier New][COLOR=#0000bb]MySQL Error   [/COLOR][COLOR=#007700]: [/COLOR][COLOR=#0000bb]Out of memory [/COLOR][COLOR=#007700]([/COLOR][COLOR=#0000bb]Needed 8388580 bytes[/COLOR][COLOR=#007700])[/COLOR][/FONT]

You should speak to your host regarding this.

[khalid]

Thanks Trevor for your hint. I will give you more details which may help.
Mysql server works on a dedicated seprate server from my http server with 6 GB of RAM. Number of records in blog table is only 480 records. Number of records in my post table is more than 9 million posts.
First Question: Why do I get out of memory for a small table like blog but works fine with table like posts (viewing posts, adding replies, editing ... etc). To me this is a small query on a small number of records and should not give out of memory.

Second Question: I have full control of the database server but I don't know where to increase the momery limit. Can you help please.