
Date:    Mar/30/94
Subject: Intimate Shared Memory (ISM) bug and bugfix detail for
	 systems running database management systems.

Please first review the patch readme file.  This special notice
provides more detail regarding the bug and bugfix issues related
to the IMS problem.
 
In brief, the problem is caused partially because Solaris 2.3 did not
perform sufficient checking, and partially by the DBMS (Sybase, Oracle,
and Informix) vendors that did not follow the Sun API to pass 16MB aligned
addresses.  The complete solution is to have both the 101318 patch, rev
34 or higher, for Solaris 2.3 AND the corresponding fixes from the
DBMS vendors.

However, it is NOT required for the customer to wait for the DBMS
fixes before applying the 101318 patch.  With just the 101318 patch
installed, the current DBMS version may not come up right away, but
WORK AROUNDS EXIST to bring up all three DBMS to be fully functional
(probably with some performance penalty, but the risk of running into
the 2 ISM bugs/panics are eliminated).  Following is more information on
what are the affected Solaris/Sybase/Oracle/Informix/Ingres releases,
available dates of various patches/EBFs/releases, as well as the work
around for various DBMS:

Solaris:
--------
	This is a Solaris 2.3 issue only.  The problem should not exist
        prior to Solaris 2.3 and therefore a similar patch need does not
        exist for releases previous to 2.3.

Sybase:
-------
	Sybase 4.9.2 or earlier does not use ISM by default, and should
	have no problem.

	Sybase System 10 use ISM by default.  Without the 101318 patch,
	dataserver comes up but Solaris may panic.  With the patch,
	and with certain memory configurations, a small number of 
  	sites may experience a situation where the Sybase SQL Server 
 	may fail to boot. If this occurs, contact Sybase Technical 
  	Support for assistance and refer to Sybase fix, EBF 2594.

Oracle:
-------
	V7.0.15 uses ISM by default.  Without the 101318 patch, database
	comes up but Solaris may panic.  With the patch, database may not
	come up.  Work around is to make sure that the shmsys:shminfo_shmmax 
	parameter in /etc/system is set to value smaller than or equal to 
	the real physical memory the machine has, AND greater than or equal 
	to the value of (db_block_buffers * 2048) in the init.ora file.  
	Oracle will not fix this version.

	V7.0.16 turns off ISM by default (expect performance penalty).  
	No problem with or without the 101318 patch.  But if customers turn 
	on ISM by setting the use_ism parameter in init.ora, they are at
	risk.  In this case, customer should install the 101318 patch and
	apply the work around described in the previous paragraph.  

	Oracle also has a V7.0.16 patch now available free of charge to 
	customers.  Oracle's patch makes sure the 16MB alignment requirement 
	is met.  However, the Oracle patch does not turn ISM back on.  
	After applying both Solaris ISM patch and Oracle's patch, customers 
	can set use_ism to 1 in init.ora for better performance.

	Oracle will integrate their fix into V7.1.3 to be available in May.

Informix:
---------
	Informix will not fix Online 5.01, which is their current production
	release.  Without the 101318 patch, database comes up but Solaris may 
	panic.  With the patch, database may not come up.  Work around 
	is to make sure the shmsys:shminfo_shmmax parameter is set to multiple 
	of 16M in /etc/system.  Another work around is to turn off RESIDENCY
	in the Informix config file, which disables ISM, but expect big 
	performance penalty.

	Informix's fix will appear in the production version of Online 6.0,
 	which will ship in April/May.

Ingres:
-------
	Ingres current release should not be affected.


