Hi,

it seems to be a never-ending story but I'll keep sharing our experiences on 
this odyssee with you.

We can now rule out connections being used for a long time as a reason for 
running out of memory. We set a low session timeout and together with the 
reconnect feature of the JDBC driver achieved that connections were never 
older than a few minutes (we monitored that). In addition to that we adjusted 
the database configuration in terms of MAXUSERTASKS and cache settings in 
such a way that memory use was reduced drastically just to rule out that the 
system doesn't have enough memory (the total mem is 2GB, 1GB of which is used 
by the application server and apart from a little system overhead the rest is 
available to sapdb).

however, it did crash again a few days later (same symptoms, malloc failing)! 
what is strange is how memory use of the sapdb kernel is displayed by the top 
utility. we monitored the following values:

SIZE (manpage: The size of the task's code plus data plus stack space, in 
kilobytes, is shown here)

RSS (manpage: The total amount of physical memory used by the task, in 
kilobytes, is shown here. For ELF processes used library pages are counted 
here, for a.out processes not.)

After a few hours of running RSS stabilized at around 130M. However SIZE never 
stopped growing becoming several times larger than RSS until the kernel 
crashed. Now it is a bit embarrassing as I don't really know under which 
circumstances these values should diverge so much. At all times the 'free' 
command showed enough memory in the system (we did occasional checks for a 
few days and there always were a few hundred M left in adding free, cache and 
buffers). 

Does this give any of you sap kernel developers a clue? Now just to repeat the 
basics of the system, we're using Linux Kernel 2.4. and SAPDB kernel version  
X32|LINUX 7.3.0    Build 025-000-085-912, for details see the archive.

I hope this is one more piece in the puzzle to solve this mystery. 

Thanks in advance,

Robert

  
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