Re: Interesting PGA/Memory puzzle (4030 error at 32GB used) - ulimit settings?
Date: Fri, 18 May 2018 12:34:13 -0500
Message-ID: <CAMHX9JKnm8OtA0nW7XfkgXGkwNUkSv_tQqM0TwY4ErHidnSJbA_at_mail.gmail.com>
Looks like you have a LOB handle leak or something, plenty of bugs around
temporary LOB handles etc. A single process should normally not use that
much memory anyway (if you're not holding some big PL/SQL collection or
workarea in memory).
SQL> _at_oddc koll
It was possible to limit an Oracle process private memory size with ulimit
in the old days when realfree memory allocation was not used (the regular
"data segment" was used at OS level, not mmap() calls for memory
allocation). But the "data seg size" ulimit does not limit mmap() based
private memory allocation.
I'd say you're hitting some internal heap or memory structure allocation
limitation that is reported as ORA-4030 at top level. So it's not
necessarily even an OS memory allocation call that fails, but could be some
internal Oracle check that doesn't allow growing a memory structure further
(likely the heap itself or some array pointing to all these leaked LOB
structures). This heap has 2M x 16kB chunks (slightly under 2 * 1024 *
1024). There's a somewhat similar bug 14119856 : ORA-4030 OVER 16GB PGA IS
ALLOCATED EVEN IF PGA_AGGREGATE_TARGET SET 20GB.
Tanel.
On Fri, May 18, 2018 at 11:53 AM, Chris Taylor <
christopherdtaylor1994_at_gmail.com> wrote:
> Env: 12.1.0.2 on Linux 7.4 64-bit
ORADEBUG DOC COMPONENT | grep -i koll
LOB LOB (koll, kola)
LOB_Default LOB Default (koll, kole, kokl, koxs)
LOB_DBLINK LOB DBLink (koll, kokl, kpolobr, kkxlr)
>
> So, I've been all over Oracle support and Google-ing this morning trying
> to determine a root cause for this:
>
> Here's the error and its always 32GB (ulimit settings to follow). Oracle
> doesn't have any support docs for KOLLRSZ.
>
> The reason I'm wondering about ulimits kicking in is because its always at
> 32GB. I'm betting its a memory leak but I'd like to overcome this seeming
> 32GB barrier.
>
> [TOC00001]
> ORA-04030: out of process memory when trying to allocate 16328 bytes
> (koh-kghu sessi,kollrsz)
>
> [TOC00001-END]
> [TOC00002]
> ========= Dump for incident 931836 (ORA 4030) ========
> [TOC00003]
> ----- Beginning of Customized Incident Dump(s) -----
> =======================================
> TOP 10 MEMORY USES FOR THIS PROCESS
> ---------------------------------------
>
> *** 2018-05-18 12:33:30.917
> *100% 32 GB, 2087947 chunks: "kollrsz "*
> * koh-kghu sessi ds=0x7f8047e4f178 dsprt=0x7f804ae4cf60*
> 0% 9688 KB, 77 chunks: "kllcqas:kllsltba " SQL
> QERHJ hash-joi ds=0x7f8048f2dc40 dsprt=0x7f804a5ab710
> 0% 4333 KB, 50 chunks: "permanent memory " SQL
> kxs-heap-w ds=0x7f804a5ab710 dsprt=0x7f804ae4cf60
> 0% 2503 KB, 18 chunks: "QERHJ list array " SQL
> QERHJ hash-joi ds=0x7f804a61dc30 dsprt=0x7f804a5ab710
> 0% 2432 KB, 7 chunks: "HT buckets " SQL
> QERHJ hash-joi ds=0x7f804a61dc30 dsprt=0x7f804a5ab710
> 0% 2056 KB, 2 chunks: "kllcqgf:kllsltba "
> klcliti:kghds ds=0x7f80491e9e10 dsprt=0x7f804f9a09e0
> 0% 1537 KB, 56 chunks: "QERHJ Bit vector " SQL
> QERHJ hash-joi ds=0x7f8048f2dc40 dsprt=0x7f804a5ab710
> 0% 1381 KB, 66 chunks: "free memory " SQL
> QERHJ hash-joi ds=0x7f804a61dc30 dsprt=0x7f804a5ab710
> 0% 1213 KB, 27 chunks: "free memory "
> top call heap ds=0x7f804f9a1be0 dsprt=(nil)
> 0% 1046 KB, 73 chunks: "free memory "
> top uga heap ds=0x7f804f9a1e00 dsprt=(nil)
>
>
>
> I'm wondering if there's a parameter at the OS layer limiting the session
> to 32GB
>
> ulimit -a
> -----------------------------------------
> core file size (blocks, -c) 0
> data seg size (kbytes, -d) unlimited
> scheduling priority (-e) 0
> file size (blocks, -f) unlimited
> pending signals (-i) 16506448
> max locked memory (kbytes, -l) 64
> max memory size (kbytes, -m) unlimited
> open files (-n) 131072
> pipe size (512 bytes, -p) 8
> POSIX message queues (bytes, -q) 819200
> real-time priority (-r) 0
> stack size (kbytes, -s) 32768
> cpu time (seconds, -t) unlimited
> max user processes (-u) 131072
> virtual memory (kbytes, -v) unlimited
> file locks (-x) unlimited
>
> PGA Settings are as follows on this Data Warehouse:
>
> NAME TYPE VALUE
> ------------------------------------ ----------- ------------
> pga_aggregate_limit big integer 128G
> pga_aggregate_target big integer 8G
>
>
>
-- http://www.freelists.org/webpage/oracle-lReceived on Fri May 18 2018 - 19:34:13 CEST