ORA-07445: exception encountered: core dump SIGSEGV

May 29, 2014 10:07:02 AM	~ORA-07445: exception encountered: core dump [_intel_fast_memcmp()+72] [SIGSEGV] [Address not mapped to object] [0x0] [] []
Mar 17, 2015 2:56:05 PM	~ORA-07445: exception encountered: core dump [_intel_fast_memcmp()+38] [SIGSEGV] [Address not mapped to object] [0x0] [] []

*ORA-600/ORA-7445 Error Look-up Tool 

ID 153788.1

ID 362953.1

Problem Symptoms

Whenever I check my alert log file I got the text as
Errors in file /var/opt/oracle/admin/udump/orastdby_ora_31795.trc
ORA-07445: exception encountered: core dump [_intel_fast_memcmp()+38] [SIGSEGV] [Address not mapped to object] [0x0] [] []
After checking the trace file I got,
Call Stack Trace shows: 
ksedst ksedmp ssexhd intel_fast_memcmp

Recent Changes of The Database
We have changes the CURSOR_SHARING parameter to SIMILAR from EXACT.

Cause of The Problem
This is oracle bug. Bug number 4456646. When the cursor sharing parameter is not set to EXACT this bug may fire. This occur while literal replacement when there are empty string literals in use. This bug happened in oracle version 10.2.0.1. In our environment it was RHL linux 32 bit production server.

Solution of The Problem 
Way 1: 
As a workaround disable literal replacement. You can do it by,
ALTER SYSTEM SET cursor_sharing='EXACT' SCOPE=both;
if you use spfile.

Way 2: 
This bug is fixed in 10.2.0.2 patchset. So, apply 10.2.0.2 patchset in order to fix the prolem.

Way 3: 
Apply One-off patch. Download one-off patch 4456646 from metalink and apply if that is avialable for your OS. For Linux x86 and linux x86-64 only available currently.

ABOUT THE CURSOR & CURSOR SHARING 

Cursor is a type of memory where store sql info,sql text,execution plans at all on shared pool -> library cache. And Bind variables usage the shared pool.