EAserver - Connection pool size question

Author

Connection pool size question

Iris

2005-08-26, 7:24 am

I set the max. connection pools size of connection cache to
10. When all 10 connection cache has been occupied,
EAServer cannot create a new connection to 11 user. And
EAServer prompts connection to DB error in EAServer log.

Is it a correct or normal properties of EAServer.

My EAServer version is v4.2.0

Adam Simmonds [TeamSybase]

2005-08-26, 7:24 am

Iris wrote:
> I set the max. connection pools size of connection cache to
> 10. When all 10 connection cache has been occupied,
> EAServer cannot create a new connection to 11 user. And
> EAServer prompts connection to DB error in EAServer log.
>
> Is it a correct or normal properties of EAServer.

No you should go above the set value and then any extra
connections are dropped once they are finished.

Add the following to your dbparm on sqlca.

GetConnectionOption=
'JAG_CM_FORCE'

Cheers
a.

> My EAServer version is v4.2.0

Iris

2005-08-26, 11:24 am

Adam,

GetConnectionOption=
'JAG_CM_FORCE' should set on connection
cache properties or I should code it in my program?

Iris
[color=darkred]
> Iris wrote:
>
> No you should go above the set value and then any extra
> connections are dropped once they are finished.
>
> Add the following to your dbparm on sqlca.
>
> GetConnectionOption=
'JAG_CM_FORCE'
>
> Cheers
> a.
>

Adam Simmonds [TeamSybase]

2005-08-27, 3:24 am

Iris wrote:
> Adam,
>
> GetConnectionOption=
'JAG_CM_FORCE' should set on connection
> cache properties or I should code it in my program?

In your code

SQLCA.DBParm="..."

a.

[color=darkred]
> Iris
>
>

Iris

2005-08-27, 3:24 am

Hi Adam,
My program is coded in EJB not powerbuilder. I only need to
get connection by calling datasource.getConnection. I don't
know where should I set the SQLCA information. Besides, why
this feature is not a default properties. And it is
required set it in the code?

Thanks for your quick response.
Iris
[color=darkred]
> Iris wrote:
> program?
>
> In your code
>
> SQLCA.DBParm="..."
>
> a.
>
>
> cache >>>to 10. When all 10 connection cache has been
> occupied, >>>EAServer cannot create a new connection to
> 11 user. >>>And EAServer prompts connection to DB error in
> EAServer >>>log.

Adam Simmonds [TeamSybase]

2005-08-27, 7:23 am

Iris wrote:
> Hi Adam,
> My program is coded in EJB not powerbuilder. I only need to
> get connection by calling datasource.getConnection. I don't
> know where should I set the SQLCA information. Besides, why
> this feature is not a default properties. And it is
> required set it in the code?

Sorry, I was thinking I was in easerver.powerbuilder.
There should be an equivilent property for EJB's
a.

[color=darkred]
>
> Thanks for your quick response.
> Iris
>
>

Alexander Pire

2005-08-29, 11:24 am

conn = cache.getConnection (JCMCache.JCM_FORCE);

BR

Alexander Pire

"Adam Simmonds [TeamSybase]" <adam. simmonds@REMOVEpeopl
eDOTnetDOTau> wrote
in message news:431029db@forums
-1-dub...[color=darkred]
> Iris wrote:
>
>
> Sorry, I was thinking I was in easerver.powerbuilder.
> There should be an equivilent property for EJB's
> a.
>
>

Jonathan Baker [Sybase]

2005-09-01, 8:26 pm

This is one of those things you can do, but really should not do.

The connection cache size is there to protect you, not to get in your
way. It's there to prevent too many connections being pushed to the DB
at any one time. Two things can happen if too many connections are
accessing the DB: first, you could hit the upper limit of connections
going to the DB, and second, you could overload the DB and cause it to
lower response times.

More importantly, it protects you against bugs in your code. If you
aren't releasing connections, or you have a runaway client, the cache
acts as a warning mechanism and prevents things from getting out of control.

The connection cache offers an invisible way to work around these two
problems. First, it limits the number of connections going out to the
DB directly. This allows the system admin to tune the cache, to
maximize performance. Second, it offers an invisible locking mechanism
that forces programs to wait until a connection does become available.
Handling that in code would take additional effort and debugging.

If you are running short of connections in the cache, try pushing the
cache limit up. If that causes performance degradation on the DB, then
find the best number, and allow the application to hold for the connections.

Cache tuning is a variant of performance tuning. It's there to help you
- bypassing it just makes your work harder down the line.

Cheers,
Jonathan

Adam Simmonds [TeamSybase] wrote:[color=darkred
]
> Iris wrote:
>
>
>
> No you should go above the set value and then any extra connections are
> dropped once they are finished.
>
> Add the following to your dbparm on sqlca.
>
> GetConnectionOption=
'JAG_CM_FORCE'
>
> Cheers
> a.
>

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