sqlrelay-discussion

[Sqlrelay-discussion] Oracle-related memory mismanagement

[Cameron L. <cla...@gm...>]

A Linux-based Oracle listener seems to require 500 MB.  That feels ...
crazy.  Listeners for other DMBSs typically use 50-80 MB, in our experience.
 We like SQL Relay much, and use it with many different back-ends; among
other things, this gives us plenty of practice with different technologies,
so we're confident our observations are real.
The memory use is not just disproportionate; it's an operational problem.
 Lockup-inducing memory exhaustion on our SQL Relay host is a recurring
issue for us.

What can we do?  I've found nothing in the archives of the mailing list, nor
<URL: http://sqlrelay.sourceforge.net/sqlrelay/gettingstarted/oracle.html >.
 I suspect a remedy is actually documented somewhere; I haven't found it,
though.  If no one knows better, I'll start to look at the source code ...

Re: [Sqlrelay-discussion] Oracle-related memory mismanagement

[Renat S. <sr...@st...>]

Cameron Laird wrote:
> The memory use is not just disproportionate; it's an operational 
> problem.  Lockup-inducing memory exhaustion on our SQL Relay host is a 
> recurring issue for us.
>
> What can we do?
The main problem with memory in sqlrelay is
allocation of all memory in cursor's constructor. sqlr-connection 
allocates memory for all cursors immediately after starting. See 
http://sourceforge.net/mailarchive/message.php?msg_name=49F9B0FC.901%40stacksoft.ru

 > For example if you set cursors=10 then it'll allocate 10*10*256*32k = 
800M.

10 - N of cursors
10 - fetch 10 rows at once
256 - N of columns
32k - memory for one column

This memory allocation strategy cause big problems on sun solaris where 
memory limit for one user by default is 1/4 of physical memory.