Tag: pga

Database, Errors and Bugs

19c+ DBMS_STATS.GATHER_TABLE_STATS Memory Leaking on PGA

 , , , , ,

Hi all,

So, here is a quick post but which wasn’t so eaasy to be mapped, though.

It happens that right after a 19c upgrade from 18c, we started facing Memory Leak messages related to PGA area on a regular basis. After a while following the v$process_memory allocation, it was possible to map it to an ODI routing with DBMS_STATS.GATHER_TABLE_STATS. The PGA exceeds the limit just a few minutes after.

Nice han, so what is happening?

Long story short: Bug 30846782 : 19C+ FAST/EXCESSIVE PGA GROWTH WHEN USING DBMS_STATS.GATHER_TABLE_STATS.

According to Oracle Docs: No Workaround!

But here is the golden info I want to share after an SR:

EXECUTE IMMEDIATE 'alter session set "_fix_control"='20424684:OFF';

You are welcome!

Cheers!

Database, Errors and Bugs

ORA-04030: out of process memory when trying to allocate % bytes (kkoutlCreatePh,ub1 : kkoabr)

 , , ,

Hi all,

So, I started seen this on a client environment. Researching on the  case after no crear reference on MOS, I noticed some high PGA allocation as per below.

SYS@proddb AS SYSDBA PROD> select pid, serial#,category, allocated/1024/1024 MB, used/1024/1024 MB_used, max_allocated/1024/1024 MB_MAX_ALLOCATED_ON_PGA
2 from v$process_memory where pid=852;

PID SERIAL# CATEGORY MB MB_USED MB_MAX_ALLOCATED_ON_PGA
---------- ---------- --------------- ---------- ---------- -----------------------
852 91 SQL .086807251 .00806427 .672416687
852 91 PL/SQL .087730408 .078926086 .126182556
852 91 Freeable .5625 0
852 91 Other 2.25187302 2.25187302

Seems a match MOS ORA-04030 Error With High “kkoutlCreatePh” (Doc ID 1618444.1).

The solution? Simply disabled the following parameter:

"_b_tree_bitmap_plans"=false

 

Trace for additional info:

Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Advanced Analytics and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/12.1.0/db_1
System name: Linux
Node name: proddb.local
Release: 4.1.12-94.8.3.el7uek.x86_64
Version: #2 SMP Wed Apr 25 19:57:32 PDT 2018
Machine: x86_64
Instance name: proddb
Redo thread mounted by this instance: 1
Oracle process number: 854
Unix process pid: 28899, image: oracle@proddb.local

*** 2019-01-09 11:20:09.130
*** SESSION ID:(5429.55092) 2019-01-09 11:20:09.130
*** CLIENT ID:() 2019-01-09 11:20:09.130
*** SERVICE NAME:(XXXXX) 2019-01-09 11:20:09.130
*** MODULE NAME:(JDBC Thin Client) 2019-01-09 11:20:09.130
*** CLIENT DRIVER:(jdbcthin) 2019-01-09 11:20:09.130
*** ACTION NAME:() 2019-01-09 11:20:09.130

[TOC00000]
Jump to table of contents
Dump continued from file: /u01/app/oracle/diag/rdbms/proddb/proddb/trace/proddb_ora_28899.trc
[TOC00001]
ORA-04030: out of process memory when trying to allocate 34392040 bytes (kkoutlCreatePh,ub1 : kkoabr)

[TOC00001-END]
[TOC00002]
========= Dump for incident 2710965 (ORA 4030) ========
[TOC00003]
----- Beginning of Customized Incident Dump(s) -----
=======================================
TOP 10 MEMORY USES FOR THIS PROCESS
---------------------------------------
72% 18 GB, 1356 chunks: "free memory " SQL
kxs-heap-c ds=0x7fa8df330220 dsprt=0x7fa8df49dbe0
27% 6809 MB, 3366 chunks: "permanent memory " SQL
kxs-heap-c ds=0x7fa8df330220 dsprt=0x7fa8df49dbe0
0% 100 MB, 894 chunks: "permanent memory " SQL
kkoutlCreatePh ds=0x7fa8cce16708 dsprt=0x7fa8df330220
0% 23 MB, 589515 chunks: "chedef : qcuatc "
TCHK^2a9688d9 ds=0x7fa8df33feb8 dsprt=0x7fa8df49c9e0
0% 18 MB, 150124 chunks: "opndef: qcopCreateOpnViaM "
TCHK^2a9688d9 ds=0x7fa8df33feb8 dsprt=0x7fa8df49c9e0
0% 16 MB, 214829 chunks: "logdef: qcopCreateLog "
TCHK^2a9688d9 ds=0x7fa8df33feb8 dsprt=0x7fa8df49c9e0
0% 11 MB, 241 chunks: "free memory "
top call heap ds=0x7fa8df49dbe0 dsprt=(nil)
0% 9643 KB, 4623 chunks: "qkkele " SQL
kxs-heap-c ds=0x7fa8df330220 dsprt=0x7fa8df49dbe0
0% 6534 KB, 58578 chunks: "optdef: qcopCreateOptInte "
TCHK^2a9688d9 ds=0x7fa8df33feb8 dsprt=0x7fa8df49c9e0
0% 4134 KB, 15399 chunks: "kccdef : qcsvwsci "
TCHK^2a9688d9 ds=0x7fa8df33feb8 dsprt=0x7fa8df49c9e0

=======================================
PRIVATE MEMORY SUMMARY FOR THIS PROCESS
---------------------------------------
******************************************************
PRIVATE HEAP SUMMARY DUMP
25 GB total:
25 GB commented, 794 KB permanent
12 MB free (0 KB in empty extents),
24 GB, 1 heap: "kxs-heap-c " 67 KB free held
------------------------------------------------------
Summary of subheaps at depth 1
25 GB total:
203 MB commented, 6809 MB permanent
18 GB free (0 KB in empty extents),
6398 MB, 9243 chunks: "allocator state " 6398 MB free held
3758 MB, 4623 chunks: "qkkele " 3749 MB free held
3650 MB, 4623 chunks: "qkkkey " 3650 MB free held

=========================================
REAL-FREE ALLOCATOR DUMP FOR THIS PROCESS
-----------------------------------------

Dump of Real-Free Memory Allocator Heap [0x7fa8df317000]
mag=0xfefe0001 flg=0x5000003 fds=0x0 blksz=65536
blkdstbl=0x7fa8df317010, iniblk=524288 maxblk=524288 numsegs=318
In-use num=2965 siz=641597440, Freeable num=0 siz=0, Free num=254 siz=3586195456

==========================================
INSTANCE-WIDE PRIVATE MEMORY USAGE SUMMARY
------------------------------------------

Dumping Work Area Table (level=1)
=====================================

Global SGA Info
---------------

global target: 102400 MB
auto target: 62376 MB
max pga: 2048 MB
pga limit: 4096 MB
pga limit known: 0
pga limit errors: 0

pga inuse: 33104 MB
pga alloc: 35238 MB
pga freeable: 1225 MB
pga freed: 433664026 MB
pga to free: 0 %
broker request: 0

pga auto: 12 MB
pga manual: 0 MB

pga alloc (max): 35238 MB
pga auto (max): 12284 MB
pga manual (max): 2 MB

# workareas : 0
# workareas(max): 551