Re: jBASE 4.1.5.17 - does anyone face "out of memory" problems after SSELECT?

[Pawel (privately)]

Hi Jim, After deeper observations we think that this is exactly what is happening. I have shown one stupid process that allocated almost 2 GB of memory (soon it crashed), but this is really exceptional. Our COB sessions (tSA) allocate a lot of memory on SSELECTs and free most of it immediately. I think that you can easily notice that sorting, not keys selections increases memory consumption. I am not showing here output from WHERE (V for all processes, but "Free" gives high amounts in total. We have analysed also nmon results and you can observe that memory consumption during COB is always growing. There are almost no points when it falls down (there are such points in fact, because COB is usually stopped once during night and processes stopped). This is well visible, but totals of "Free" in processes (at some point of time) may give serious amounts. I am not really 100% sure how memory is allocated by malloc - in pages, right? So will MALLOCOPTION=disclaim give back (fully) unused pages to the OS? Will it happen only when there is out of physical memory? Additionally: how can we control page size? (size of chunks of memory being allocated?) Is it advisable to change it? I am going to give you results of some simple program soon. We will try to test allocators on our test server over a weekend. I know that .profile changes should be considered as dangerous and well pretested (considered as configuration changes). We did not get response from CSHD yet, but I am sure they will answer shortly. Kind regards Pawel Dnia 10-02-2009 o godz. 17:30 Jim Idle napisał(a): Pawel (privately) wrote: Hi,   Thank you for all responses. I am reading AIX materials and started from IBM link that Jim sent (malloc subsystem explanations).   Is it all about: Malloc Disclaim Malloc Disclaim is an optional extension of the malloc subsystem, providing the user with a means to enable the automatic disclaiming of memory returned by the free subroutine. This is useful in instances where a process has a high paging-space usage, but is not actually using the memory. Malloc Disclaim is not enabled by default. It can be enabled and configured prior to process startup through the MALLOCOPTIONS environment variable, as follows: MALLOCOPTIONS=disclaim We are going to test "Watson" more carefully and play with MALLOCOPTIONS. Be sure that you will hear me again :) This won't help you I think because that isn't what is happening. The output of WHERE (V isn't telling you that there is a lot of memory that has been freed but not disclaimed, it is telling you that it is in use. I think that there has been some confusion over what Pat said about the mw42 command output vs your WHERE (V output. That (WHERE output) is NOT a high watermark, it is telling you what is actually used! In fact this option may make performance worse for you in some cases, because unless your system has begun page swapping, there is no need to return the address space to the system. Be careful with your experimentation. First just turn on watson, then start playing with MALLOCOPTIONS - these things are not really there to just play with to be honest, you really need to understand how the whole thing works to get any benefit other than randomly ;-) You just need to turn on watson now and see if there is any difference. It think that there will be and that things won't be any worse. If there is a memory leak, then nothing will change really (though it might allow the process to get through the work). Otherwise you either need help to show definitively that this is a memory leak, or you need to get some serious input from TEMENOS technicians (not help desk answers I am afraid). Jim ---------------------------------------------------- Weź udział w akcji: Zakochana Polska! Prześlij "serducho miłości" - Kliknij: http://klik.wp.pl/?adr=http://corto.www.wp.pl/as/14luty.html&sid=637 --~--~---------~--~----~------------~-------~--~----~ Please read the posting guidelines at: http://groups.google.com/group/jBASE/web/Posting%20Guidelines IMPORTANT: Type T24: at the start of the subject line for questions specific to Globus/T24 To post, send email to jBASE@googlegroups.com To unsubscribe, send email to jbase-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/jBASE?hl=en -~----------~----~----~----~------~----~------~--~---