Re: JDBC Driver Settings
- From: "chinn" <chinn@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Wed, 4 May 2005 06:31:11 -0700
Shelby
Thanks Very Much For Explaining that.
Are there any settings we can tweak when using SelectMethod=Cursor..IF so
what are good and bad
Thanks,
"Shelby Goerlitz [MSFT]" wrote:
> Chinn:
>
> Yes, this is correct -- see below a quote from the Connection String
> Properties section of the docs.
>
> ===
> Direct-The direct method sends the complete result set in one
>
> request to the driver. It is useful for queries that only produce a
>
> small amount of data that you fetch completely. You should avoid
>
> using direct when executing queries that produce a large amount
>
> of data, as the result set is cached completely on the client and
>
> constrains memory. In this mode, each statement requires its own
>
> connection to the database. This is accomplished by "cloning"
>
> connections. Cloned connections use the same connection
>
> properties as the original connection; however, because
>
> transactions must occur on a single connection, auto commit
>
> mode is required. Due to this, JTA is not supported in direct mode.
>
> In addition, some operations, such as updating an insensitive
>
> result set, are not supported in direct mode because the driver
>
> must create a second statement internally. Exceptions generated
>
> due to the creation of cloned statements usually return an error
>
> message similar to "Cannot start a cloned connection while in
>
> manual transaction mode."
>
> ===
>
> -shelby
>
> Shelby Goerlitz
> Microsoft, SQL Server
>
>
>
> "chinn" <chinn@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:BDF3530D-CF92-43E6-85B2-9E0D0DAFF400@xxxxxxxxxxxxxxxx
> > Carb,
> >
> > But somebody is saying this..
> >
> > Is this correct..
> >
> > Microsoft JDBC driver doesn't support 'DIRECT' select mode for
> > XADatasources
> > (XA database connections). So we have to use cursor method.
> > When I tried to switch to Direct, App didn't start with the error that
> > 'direct' select method can not be used for XA Connections.
> >
> > thanks,
> >
> > ""Carb Simien [MSFT]"" wrote:
> >
> >>
> >> --------------------
> >> | Thread-Topic: JDBC Driver Settings
> >> | thread-index: AcVKCoOrRDJWhsIWSTSRvlg4RlTrKQ==
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> >> | From: "=?Utf-8?B?Y2hpbm4=?=" <chinn@xxxxxxxxxxxxxxxxxxxxxxxxx>
> >> | Subject: JDBC Driver Settings
> >> | Date: Mon, 25 Apr 2005 19:49:06 -0700
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> >> |
> >> | Hello,
> >> | I saw the below in one of settings..where do i find them and where are
> >> they
> >> | defined..
> >> |
> >> |
> >> | see lot of select statements with sp_cursoropen with thousands of
> >> reads
> >> in
> >> | the
> >> | profiler but if i take the query and run it in the QA it will be 1/4 of
> >> | those reads .I
> >> | am wondering we will have to tweak somethings like you mentioned
> >> below.Could
> >> | you help me to find out where i could find those settings like
> >> fetchsize
> >> and
> >> | selectmode..
> >> |
> >> |
> >> | If you do decide to use cursor mode with ResultSets defined as
> >> | TYPE_FORWARD_ONLY and either CONCUR_READONLY or CONCUR_UPDATABLE, then
> >> you,
> >> | you can additionally test various values for the fetch size to tune
> >> the
> >> | performance. Otherwise, your fetch size will only be 1.
> >> |
> >> |
> >> |
> >>
> >> You can set the fetch size using the setFetchSize() method from your
> >> Statement/PreparedStatement/CallableStatement object. SelectMethod can
> >> be
> >> set to either Direct or Cursor, and this is done in the connection
> >> string:
> >>
> >> SelectMethod=cursor
> >>
> >> or
> >>
> >> SelectMethod=direct
> >>
> >> The default is Direct.
> >>
> >> Carb Simien, MCSE MCDBA MCAD
> >> Microsoft Developer Support - Web Data
> >>
> >> Please reply only to the newsgroups.
> >> This posting is provided "AS IS" with no warranties, and confers no
> >> rights.
> >>
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> >>
> >>
>
>
>
.
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