apc-aa-coders

[Apc-aa-coders] pagecache insert. update, replace problem

[Michael M. <mi...@gn...>]

Hi

we're running fairly recent AA version (think very close to SVN) and have 
noticed occasional reports of this type:

> ', '1181223016', '1f34283960f6cfd631c60ef26383c170' )
> Error Number (description): 1062 (Duplicate entry
> '1f34283960f6cfd631c60ef26383c170' for key 1) Please contact
> tec...@gn... and report the exact error message. Session halted.
>
> Sidebar on right
> Database error: Invalid SQL: INSERT INTO pagecache ( `content`, `stored`,
> `id` ) VALUES ( '

My theory to what happens is that there are maybe two similar request - at 
least they create same or similar keystr) and then one "overtakes" the other 
one and ends up stealing its id.
But that's only a theory really and would need some debugging. For the moment 
I'm wondering whether anybody else gets those?

Thanks,

mimo

Re: [Apc-aa-coders] pagecache insert. update, replace problem

[Norbert B. <br...@ch...>]

Hi Michael,

Michael Moritz wrote:
> My theory to what happens is that there are maybe two similar request - at 
> least they create same or similar keystr) and then one "overtakes" the other 
> one and ends up stealing its id.
> But that's only a theory really and would need some debugging. For the moment 
> I'm wondering whether anybody else gets those?
>   
It is either problem with duplicate ids being generated by AA or problem
caused by not using sql transactions during cache update.

The problem might be caused by two cache inserts (insert into pagecache
and insert into pagecache_str2find) for each cached page which are not
"encapsulated" in transaction. So under high cache update load there are
several concurent cache updates for the same record. I believe that
those can result in such duplicates.


n.