database Share Memory Limit (2 GB ) in a Instance is total of all Db shared memory of all databases in a single Instance!!

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sadanjan@gmail.com - 21 Jul 2006 13:57 GMT

Hi ,

Appreciate if someone can clarify if database Share Memory Limit
(2 GB ) in Unix 32 bit boxes is the top limit for all the databases
put together in a database or is it for each of the database in an
Instance

Thanks & regards
sadanjan

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Liam Finnie - 21 Jul 2006 16:46 GMT

> Hi ,
>
[quoted text clipped - 5 lines]
> Thanks & regards
> sadanjan

Hi Sadanjan,

This limit is per-database, you can have multiple active databases,
with each database using the 2GB limit on UNIX 32-bit instances (on
Windows 32-bit, the overall sum of memory used by DB2 is limited to the
2GB virtual memory limit, or 3GB using the special /3GB boot option).
However, depending on your particular OS (AIX/Linux/Solaris/HP-UX), you
might need to do some OS and DB2 tuning to be able to actually allocate
the full 2GB for the database. Also, this will limit the amount of
instance-wide shared memory (INSTANCE_MEMORY), and private memory
(stmtheap, applheapsz, etc) that can be allocated. If your databases
are already pushing close to this limit, you're probably better off
using the 64-bit version of DB2.

Cheers,
Liam.

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Mark A - 21 Jul 2006 22:20 GMT

> Hi Sadanjan,
>
[quoted text clipped - 12 lines]
> Cheers,
> Liam.

I believe that the 2GB limit is per instance not per database. However, you
can easily have more than one instance per server.

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Pierre Saint-Jacques - 22 Jul 2006 05:37 GMT

No the limit is per db.
It's the Global Shared Memory of the db that is limited by the 2GB.
If memory serves, the limit is actually 1.75 GB for single node, single
processor. 1.5 GB if either Database Partionning Facility or Synetric Muti
Processor enabled (Poof! there went another 256MB segment). A look at the
Quick Beginnings specifies all of this for each OS and its versions.
HTH, Pierre.

Signature

Pierre Saint-Jacques
SES Consultants Inc.
514-737-4515

>>
>> Hi Sadanjan,
[quoted text clipped - 16 lines]
> I believe that the 2GB limit is per instance not per database. However,
> you can easily have more than one instance per server.

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