Hi Larry,
Please find my responses in-line.
On Mon, 2006-08-21 at 10:01 -0700, Larry White wrote:
> Folks:
>
> I have a few comments and questions about the connection pool
> features,
> particularly from the perspective of HADB's use of the jdbc-resource
> and
> connection-pool.
>
> The high level question is: will we still be able to use the existing
> non-clustered
> connection pool with no issues of compatibility?
Yes. ClusteredPool is a new feature. It does not affect normal
connection pools. Please refer the onepager for more details for the
env.
in which ClusteredPools will be of use.
> We do not want to introduce
> any regressions caused by this new feature.
>
> I am seeing some important problems in the semantics you propose for
> the behavior of this clustered pool particularly if we tried to use it
> with HADB.
> For example, your one-pager has the following:
>
> "The connections are load-balanced and failed-over to healthy nodes
> only during connection request from the application. There is no
> fail-over support for connections of in-flight transactions.
> ClusteredPool uses the connection-validation feature of the connection
> pool. When a connection is requested by the application,
> clustered-pool will choose a pool from its list and validates the
> connection. If the validation is successful, connection is returned to
> the user. If the connection is invalid, clustered-pool will fail-over
> to other available pools. All connections in the failed-pool will be
> dropped."
>
> The problem here is that we already have (with HADB) a
> well-established and tested mechanism whereby an attempt to create a
> connection will be retried (and most often succeed) by our app server
> code calling through the HADB JDBC driver. In this situation, it
> would be very very bad to do what you state in the last sentence here:
> "All connections in the failed-pool will be dropped."
This behavior is only for ClusteredPool.
>
> There may be more semantic issues like this and we need to scrutinize
> this very carefully,
> especially if this new type of pool is to be the only choice in the
> future.
> regards, Larry White
>
Thanks,
-Jagadish
> Jagadish Prasath Ramu wrote:
>
> > Hi,
> > We have proposed the one pager for connection pool features, which
> > involves DTD changes. (diff attached)
> >
> > we have updated the "Domain Configuration Management Process" wiki
> > page for GlassFish V2 Release
> >
> > Thanks,
> > -Jagadish, Kshitiz
> >
> >
> > ____________________________________________________________________
> >
> > ------------------------------------------------------------------------------------------------------
> > * DTD changes associated with clustered-pool
> >
> > 554a555,560
> >
> >
> > > attributes :
> > > pool-name
> > > the pool-id associated with the resource.
> > > In case of clustered-pool, it can be a comma separated
> > > list of available connection pools.
> > >
> > >
> >
> > 643a650,656
> >
> >
> > > attributes
> > >
> > > pool-name
> > > the pool-id associated with the resource.
> > > In case of clustered-pool, it can be a comma separated
> > > list of available connection pools.
> > >
> > >
> >
> >
> > Comments : This is only a description change. Now pool-name can take
> > comma-separated connection-pool ids. The DTD has no impact as such.
> > ------------------------------------------------------------------------------------------------------
> >
> >
> > * DTD change associated with introduction of sun-specific-property
> >
> > 2569a2583,2621
> >
> >
> > > sun-specific-property
> > > To enable application server specific connection pool features.
> > > (See <sun-specific-property>)
> > >
> > > The following are the names and corresponding description for these
> > > properties
> > >
> > > LeakTracing
> > > To aid user in detecting potential connection leaks by
> > > application.
> > >
> > > ConnectionLeakTimeout
> > > The period after which connection is considered to
> > > be leaked.
> > >
> > > ConnectionCreationRetry
> > > To retry connection creation for specific number of
> > > times, at specified intervals
> > >
> > > ConnectionCreationRetryAttempts
> > > The number of attempt to create a new connection
> > > when requested by application
> > >
> > > ConnectionCreationRetryInterval
> > > The time interval between successive retry to create
> > > a connection
> > >
> > > ValidateAtmostPeriod
> > > Validates atmost once in the specified time-interval
> > >
> > > StatementTimeout
> > > Sets the timeout property of a connection to enable
> > > termination of abnormally long running queries.
> > >
> > > PollInterval
> > > The time interval between successive polling of failed node.
> > > Applicable only for clustered pool.
> > >
> > >
> >
> > 2725c2777
> > < <!ELEMENT jdbc-connection-pool (description?, property*)>
> > ---
> >
> >
> > > <!ELEMENT jdbc-connection-pool (description?, sun-specific-property* property*)>
> > >
> >
> > 2762a2815,2849
> >
> >
> > > sun-specific-property
> > > To enable application server specific connection pool features.
> > > (See <sun-specific-property>)
> > >
> > > The following are the names and corresponding description for these
> > > properties
> > >
> > > LeakTracing
> > > To aid user in detecting potential connection leaks by
> > > application.
> > >
> > > ConnectionLeakTimeout
> > > The period after which connection is considered to
> > > be leaked.
> > >
> > > ConnectionCreationRetry
> > > To retry connection creation for specific number of
> > > times, at specified intervals
> > >
> > > ConnectionCreationRetryAttempts
> > > The number of attempt to create a new connection
> > > when requested by application
> > >
> > > ConnectionCreationRetryInterval
> > > The time interval between successive retry to create
> > > a connection
> > >
> > > ValidateAtmostPeriod
> > > Validates atmost once in the specified time-interval
> > >
> > > PollInterval
> > > The time interval between successive polling of failed node.
> > > Applicable only for clustered pool.
> > >
> > >
> >
> > 2825c2912
> > < <!ELEMENT connector-connection-pool (description?, security-map*, property*)>
> > ---
> >
> >
> > > <!ELEMENT connector-connection-pool (description?, security-map*, sun-specific-property*, property*)>
> > >
> >
> > 2955a3043,3055
> >
> >
> > > <!-- sun-specific-property
> > > Syntax for providing application server specific features for
> > > connection-pool
> > >
> > > Used in:
> > > connector-connection-pool, jdbc-connection-pool
> > >
> > > -->
> > > <!ELEMENT sun-specific-property (description?)>
> > >
> > > <!ATTLIST sun-specific-property
> > > name CDATA #REQUIRED
> > > value CDATA #REQUIRED>
> > >
> >
> >
> > Comments : The above is list of DTD changes for introduction of sun-specific property.
> > An optional element sun-specific-property is introduced for jdbc and connector
> > connection-pool. It is similar to element property. It will hold name and value pair.
> >
> > ------------------------------------------------------------------------------------------------------
> >