maria-developers team mailing list archive

[Puneet Dewan <puneetd30@xxxxxxxxx>]

Hi Vladislav,

Back when created this class , I thought something along the lines of usual
OO technique - single interface,  2 different concrete implementations
classes .  Connection.prepareStatement()
would serve then as a factory method -dependent on useServerPrepStmt
connection parameter it would create either MySQLPreparedStatement or
MySQLServerSidePreparedStatement


I agree with your concerns and initially it was coded in the above way.

The answer which you gave :
This is easy to explan and can also be  easily found  with bzr, or
Launchpad. The file was added in revision 424
http://bazaar.launchpad.net/~maria-captains/mariadb-java-client/trunk/revision/424
.. The comment says

"CONJ21- allow ResultSetMetaData to be retrieved  from preparedStatement,
before statement is executed.

Fix is using server-side prepared statement functionality - prepare command
will return result set metadata among other information. Introduce
MySQLServerSidePreparedStateme
nt class, which in the future will be able to provide  full-featured
PreparedStatement functionality, using server side prepared statements
internally."


This is the fix for the bug https://mariadb.atlassian.net/browse/CONJ-21 ,
to allow users to retrieve ResultSetMetadata  priorto /without the
 execution of statement. This is only possible with server-side "prepare",
no other way around it
The class was meant to be expanded in the future, as the comment said.

Thanks for the above .Neither me nor my mentors were aware about this I
guess and that's the reason we decided to add the useServerPrepStmts
feature using MySQLPreparedStatement.

I will discuss with my mentors and continue posting on the steps being
taken.


Thanks & Regards
Puneet.






On Sun, Jun 8, 2014 at 4:08 PM, Vladislav Vaintroub <wlad@xxxxxxxxxxxxxxxx>
wrote:

>
>
> > -----Original Message-----
> > From: Puneet Dewan [mailto:puneetd30@xxxxxxxxx]
> > Sent: Sonntag, 8. Juni 2014 00:37
> > To: Vladislav Vaintroub
> > Cc: maria-developers@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: [Maria-developers] Java Connector Coding till 5th June
> >
> Hi Puneet,
>
>
> > The advantages of creating a new class MySQLServerSidePreparedStatement
> > will be a clear separation of concerns. :)
>
> Back when created this class , I thought something along the lines of
> usual OO technique - single interface,  2 different concrete
> implementations classes .  Connection.prepareStatement()would serve then as
> a factory method -dependent on useServerPrepStmt connection parameter it
> would create either MySQLPreparedStatement or
> MySQLServerSidePreparedStatement
>
> I am by no means a big fan of everything object-oriented or of design
> patterns , however in this case the alternative to server-side specific
> implementation class seems to be a lots of "if" statements  mixed into in
> existing  MySQLPreparedStatement methods .Given that PreparedStatement
> itself is a rather large interface, I'm afraid that code will go spaghetti
> way rather easily.
>
> > I will discuss with my mentors this week and take the necessary
> steps.Will
> > continue posting about the steps taken.
> >
>
> > Regards
> >
> > Puneet.
> >
> >
> >
> >
> >
> >
> >
> > On Sun, Jun 8, 2014 at 2:04 AM, Vladislav Vaintroub
> > <wlad@xxxxxxxxxxxxxxxx> wrote:
> >
> >
> >
> >
> >       > -----Original Message-----
> >       > From: Puneet Dewan [mailto:puneetd30@xxxxxxxxx]
> >       > Sent: Samstag, 7. Juni 2014 03:58
> >       > To: Vladislav Vaintroub
> >       > Cc: maria-developers@xxxxxxxxxxxxxxxxxxx
> >       > Subject: Re: [Maria-developers] Java Connector Coding till 5th
> June
> >       >
> >       > Hi Vladislav,
> >       >
> >       >
> >       > Honestly, initially I had thought of using
> >       > MySqlServerSidePreparedstatement.
> >       > But after discussion with Georg, I understood it was an overhead.
> >
> >       This is why I asked. I'm wondering what was the overhead exactly?
> > And what is the plan to avoid the overhead? Is it to squeeze second
> > implementation of java.sql.PreparedStatement interface into an already
> > existing class?
> >
> >
> >       > Even when discussed during code review with Massimo we decided
> > to add
> >       > the useserverprepstmts feature using MySqlPreparedStatement
> > and not to
> >       > use MySqlServerSidePreparedstatement.
> >       > Because this class just had a prepare and close and not a clear
> idea
> > why this
> >       > class was created and almost all methods are empty.
> >
> >
> >       This is easy to explan and can also be  easily found  with bzr, or
> > Launchpad. The file was added in revision 424
> > http://bazaar.launchpad.net/~maria-captains/mariadb-java-
> > client/trunk/revision/424 .. The comment says
> >
> >       "CONJ21- allow ResultSetMetaData to be retrieved  from
> > preparedStatement, before statement is executed.
> >
> >       Fix is using server-side prepared statement functionality - prepare
> > command will return result set metadata among other information.
> > Introduce MySQLServerSidePreparedStatement class, which in the future
> > will be able to provide  full-featured PreparedStatement functionality,
> using
> > server side prepared statements internally."
> >
> >
> >       This is the fix for the bug
> > https://mariadb.atlassian.net/browse/CONJ-21 , to allow users to
> retrieve
> > ResultSetMetadata  priorto /without the  execution of statement. This is
> only
> > possible with server-side "prepare", no other way around it
> >       The class was meant to be expanded in the future, as the comment
> > said.
> >
> >
> >       > We are not removing client side prepared statement feature, both
> > client and
> >       > server side prepared statement are there and will be used  as per
> > the
> >       > needs.I am just trying to add a useserverprepstmts feature
> >       > usingMySqlPreparedStatement and will be activated from the jdbc
> > url i.e
> >       > jdbc:mysql://localhost:3306/test?useServerPrepStmts=true.
> >       >
> >       > If useServerPrepStmts is not used client side prepared statements
> > will be
> >       > used.
> >
> >
> >       Right, this makes sense.
> >
> >
> >       >
> >       > Regards
> >       >
> >       > Puneet.
> >       >
> >       >
> >       >
> >       >
> >       > On Sat, Jun 7, 2014 at 3:02 PM, Vladislav Vaintroub
> >       > <wlad@xxxxxxxxxxxxxxxx> wrote:
> >       >
> >       >
> >       >
> >       >
> >       >       > -----Original Message-----
> >       >       > From: Maria-developers [mailto:maria-developers-
> >       >       > bounces+wlad=montyprogram.com@xxxxxxxxxxxxxxxxxxx] On
> >       > Behalf Of
> >       >       > Puneet Dewan
> >       >       > Sent: Donnerstag, 5. Juni 2014 07:43
> >       >       > To: maria-developers@xxxxxxxxxxxxxxxxxxx
> >       >       > Subject: [Maria-developers] Java Connector Coding till
> 5th
> > June
> >       >
> >       >       Hi Puneet,
> >       >
> >       >
> >       >       > 7.Then I saw that there is a class
> >       > MySqlServerSidePreparedStatement.java,
> >       >       >
> >       >       > Initially I coded the prepareStatement() ,close(),and
> execute()
> > in
> >       > that class
> >       >       > seperately.
> >       >       >
> >       >       > But after (Code review) discussion with Massimo, we donot
> > need
> >       > to use that
> >       >       > class.
> >       >
> >       >
> >       >       I'm curious. What were the  arguments for not using this
> class?
> > That
> >       > class MySqlServerSidePreparedStatement.java was created for
> > exactly the
> >       > purpose of implementing server-side prepared statements (user
> > could
> >       > choose implementation based on parameter, e.g
> > userServerPrepStmts like in
> >       > Connector/J).
> >       >
> >       >       If the idea is that people do not need client-side prepared
> >       > statements, and server-side the only correct way to go, this is,
> > based on my
> >       > experience, incorrect.  Often, people would want parametrized
> > statements
> >       > without the overhead of P_S (prepare, execute, close).
> >       >
> >       >
> >       >       > Instead use MySqlPreparedStatement.java to do the same
> > work.So
> >       > made
> >       >       > changes accordingly.
> >       >
> >       >
> >       >
> >
> >
> >
> >
>
>
>